[readme] update readme images and change version to 0.0.2

Adds decode and SPIR-V translation for the missing MUBUF, MIMG and DS
atomic instructions in the Gen5 shader translator, generalizing the
existing BufferAtomicAdd path. Covers swap, cmpswap, add, sub,
smin/smax, umin/umax, and/or/xor, inc and dec, plus the DS RTN
variants. Image atomics go through OpImageTexelPointer on the storage
image binding.

Notable: DS_CMPST operand order (DATA0 = comparator, DATA1 = new
value) is reversed relative to buffer/image cmpswap, which a dedicated
test locks in. ATOMIC_INC/DEC are approximated with
OpAtomicIIncrement/IDecrement, exact for the common 0xFFFFFFFF clamp.

Verified with 9 new synthetic decoder and end-to-end SPIR-V tests
(part of the #36 test corpus effort); full suite passes 35/35.

Signed-off-by: missatjuhvdk1 <177474143+missatjuhvdk1@users.noreply.github.com>
Co-authored-by: missatjuhvdk1 <177474143+missatjuhvdk1@users.noreply.github.com>

Directory.Build.props

@@ -9,7 +9,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
-    <SharpEmuVersion>0.0.1</SharpEmuVersion>
+    <SharpEmuVersion>0.0.2</SharpEmuVersion>
     <Version>$(SharpEmuVersion)</Version>
 
     <RepoRoot>$([MSBuild]::NormalizeDirectory('$(MSBuildThisFileDirectory)'))</RepoRoot>

README.md

@@ -23,11 +23,11 @@ SPDX-License-Identifier: GPL-2.0-or-later
   <strong>Join our Discord for development updates, compatibility discussions, support, and community chat.</strong>
 </p>
 
----
-
-> [!NOTE]  
-> SharpEmu supports Windows x64, Linux x64, and macOS x64. Apple Silicon Macs
-> can run the macOS x64 build through Rosetta 2.
+---
+
+> [!NOTE]  
+> SharpEmu supports Windows x64, Linux x64, and macOS x64. Apple Silicon Macs
+> can run the macOS x64 build through Rosetta 2.
 
 > [!WARNING]  
 > SharpEmu is an experimental PS5 emulator developed from scratch in C#. The current focus is on accuracy and infrastructure setup rather than game-specific compatibility.
@@ -60,51 +60,43 @@ Current capabilities include:
 
 Some games have reached like `sceVideoOut` and AGC stages.
 
-SharpEmu supports Windows, Linux, and macOS hosts. Video output uses Vulkan on
-Windows and Linux, and MoltenVK on macOS. Platform support is still experimental,
-so compatibility and performance vary by game, operating system, and GPU driver.
-
-## Using
-
-Download the release archive for your operating system, extract it, and launch
-SharpEmu with the path to a legally obtained game's `eboot.bin`.
-
-Windows PowerShell:
-
-```powershell
-.\SharpEmu.exe "C:\path\to\game\eboot.bin" 2>&1 |
-  Tee-Object -FilePath "SharpEmu.log"
-```
-
-Linux and macOS:
-
-```bash
-chmod +x ./SharpEmu
-
-./SharpEmu "/path/to/game/eboot.bin" 2>&1 |
-  tee SharpEmu.log
-```
-
-A Vulkan-capable GPU and current graphics driver are required. The macOS
-release includes the MoltenVK Vulkan implementation.
+SharpEmu supports Windows, Linux, and macOS hosts. Video output uses Vulkan on
+Windows and Linux, and MoltenVK on macOS. Platform support is still experimental,
+so compatibility and performance vary by game, operating system, and GPU driver.
+
+## Using
+
+Download the release archive for your operating system, extract it, and launch
+SharpEmu with the path to a legally obtained game's `eboot.bin`.
+
+Windows PowerShell:
+
+```powershell
+.\SharpEmu.exe "C:\path\to\game\eboot.bin" 2>&1 |
+  Tee-Object -FilePath "SharpEmu.log"
+```
+
+Linux and macOS:
+
+```bash
+chmod +x ./SharpEmu
+
+./SharpEmu "/path/to/game/eboot.bin" 2>&1 |
+  tee SharpEmu.log
+```
+
+A Vulkan-capable GPU and current graphics driver are required. The macOS
+release includes the MoltenVK Vulkan implementation.
 
 ## Games Tested
 
-* **Demon's Souls Remake**
-  * [Demon's Souls [PPSA01341]](https://github.com/sharpemu/sharpemu/issues/2)
-  * Demon's Souls is now video loop. Shaders are ready to be converted to SPIR-V/Vulkan. We are continuing our work on this.
-  ![DeS videoOut submit first frame](./.github/images/des-videoout-shaders.jpg)
+|               Demons Souls Remake                   |                     Dreaming Sarah                         |
+| :-----------------------------------------------------------: | :--------------------------------------------------------------------------------------------: |
+| ![Bloodborne screenshot](./.github/images/demons-souls.jpg) | ![Dreaming Sarah](./.github/images/dreaming-sarah.jpg) |
 
-* **Poppy Playtime Chapter 1**
-  * [Poppy Playtime Chapter 1 [PPSA20591]](https://github.com/sharpemu/sharpemu/issues/3)
-
-* **SILENT HILL: The Short Message**
-  * [SILENT HILL: The Short Message [PPSA10112]](https://github.com/sharpemu/sharpemu/issues/4)
-
-* **Dreaming Sarah**
-  * [Dreaming Sarah [PPSA02929]](https://github.com/sharpemu/sharpemu/issues/9)
-  * Real texture rendering for this game;
-  ![Splash texture](./.github/images/dreaming-sarah.jpg)
+|                  Void Terrarium                     |                 Dead Cells                    |
+| :------------------------------------------------------------------------: | :------------------------------------------------------------------: |
+| ![Void Terrarium](./.github/images/void-terrarium.jpg) | ![Dead Cells](./.github/images/dead-cells.jpg) |
 
 
 > [!IMPORTANT]  
@@ -114,7 +106,7 @@ release includes the MoltenVK Vulkan implementation.
 
 ## Build
 
-1. Install the .NET SDK version specified in [`global.json`](./global.json).
+1. Install the .NET SDK version specified in [`global.json`](./global.json).
 2. Clone the repository: `git clone https://github.com/sharpemu/sharpemu.git`
 3. Open the solution file (`SharpEmu.slnx`) in **VSCode**.
 4. Build the project: `dotnet build` or `dotnet publish`

src/SharpEmu.CLI/Program.cs

@@ -63,6 +63,11 @@ internal static partial class Program
 
     private static int Run(string[] args)
     {
+        if (Updater.TryApply(args, out var updateExitCode))
+        {
+            return updateExitCode;
+        }
+
         args = NormalizeInternalArguments(args, out var isMitigatedChild);
         if (args.Length == 0 && !isMitigatedChild)
         {

src/SharpEmu.Core/Cpu/Emulation/BmiInstructionEmulator.cs

@@ -0,0 +1,305 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Numerics;
+
+namespace SharpEmu.Core.Cpu.Emulation;
+
+/// <summary>
+/// Pure software implementations of the BMI1, BMI2 and ABM general-purpose-register
+/// bit-manipulation instructions.
+///
+/// The direct-execution backend runs guest PS5 code natively on the host CPU. The PS5's
+/// Zen 2 cores implement BMI1/BMI2/ABM, but a host CPU that predates those extensions raises
+/// #UD (STATUS_ILLEGAL_INSTRUCTION) when it meets one of these opcodes. This class provides the
+/// register-only arithmetic so the exception handler can finish the instruction in software and
+/// resume, instead of aborting the title.
+///
+/// The methods deliberately operate on plain integers rather than on the OS CONTEXT record so the
+/// semantics can be unit-tested in isolation; the unsafe register/memory plumbing lives in the
+/// backend adapter. Each method returns the result already masked to the operand width and, where
+/// the instruction is defined to touch flags, updates <paramref name="eflags"/> in place. Flags
+/// documented as "undefined" by the vendor manuals are left untouched so behaviour stays
+/// deterministic across hosts.
+/// </summary>
+public static class BmiInstructionEmulator
+{
+    private const uint FlagCarry = 1u << 0;
+    private const uint FlagZero = 1u << 6;
+    private const uint FlagSign = 1u << 7;
+    private const uint FlagOverflow = 1u << 11;
+
+    private static ulong WidthMask(GprOperandSize size) =>
+        size == GprOperandSize.Bits64 ? ulong.MaxValue : 0xFFFF_FFFFUL;
+
+    private static int WidthBits(GprOperandSize size) => (int)size;
+
+    private static bool SignSet(ulong value, GprOperandSize size) =>
+        size == GprOperandSize.Bits64 ? (value >> 63) != 0 : (value & 0x8000_0000UL) != 0;
+
+    private static uint WithFlag(uint eflags, uint flag, bool set) =>
+        set ? eflags | flag : eflags & ~flag;
+
+    // Applies the CF/ZF/SF/OF set shared by ANDN/BLS*/BZHI: OF is always cleared, ZF and SF follow
+    // the result, and the caller supplies CF because each instruction defines it differently.
+    private static uint ApplyLogicFlags(uint eflags, ulong result, GprOperandSize size, bool carry)
+    {
+        eflags = WithFlag(eflags, FlagCarry, carry);
+        eflags = WithFlag(eflags, FlagZero, result == 0);
+        eflags = WithFlag(eflags, FlagSign, SignSet(result, size));
+        eflags = WithFlag(eflags, FlagOverflow, false);
+        return eflags;
+    }
+
+    /// <summary>ANDN: <c>dest = (~src1) &amp; src2</c>. CF and OF are cleared.</summary>
+    public static ulong Andn(ulong src1, ulong src2, GprOperandSize size, ref uint eflags)
+    {
+        var result = (~src1 & src2) & WidthMask(size);
+        eflags = ApplyLogicFlags(eflags, result, size, carry: false);
+        return result;
+    }
+
+    /// <summary>BLSI: isolate the lowest set bit, <c>dest = (-src) &amp; src</c>. CF = (src != 0).</summary>
+    public static ulong Blsi(ulong src, GprOperandSize size, ref uint eflags)
+    {
+        var mask = WidthMask(size);
+        var s = src & mask;
+        var result = ((0UL - s) & s) & mask;
+        eflags = ApplyLogicFlags(eflags, result, size, carry: s != 0);
+        return result;
+    }
+
+    /// <summary>BLSMSK: mask up to and including the lowest set bit, <c>dest = (src - 1) ^ src</c>. CF = (src == 0).</summary>
+    public static ulong Blsmsk(ulong src, GprOperandSize size, ref uint eflags)
+    {
+        var mask = WidthMask(size);
+        var s = src & mask;
+        var result = ((s - 1) ^ s) & mask;
+        eflags = ApplyLogicFlags(eflags, result, size, carry: s == 0);
+        return result;
+    }
+
+    /// <summary>BLSR: reset the lowest set bit, <c>dest = (src - 1) &amp; src</c>. CF = (src == 0).</summary>
+    public static ulong Blsr(ulong src, GprOperandSize size, ref uint eflags)
+    {
+        var mask = WidthMask(size);
+        var s = src & mask;
+        var result = ((s - 1) & s) & mask;
+        eflags = ApplyLogicFlags(eflags, result, size, carry: s == 0);
+        return result;
+    }
+
+    /// <summary>
+    /// BEXTR: extract <c>len</c> bits of <paramref name="src"/> starting at bit <c>start</c>, where
+    /// start = control[7:0] and len = control[15:8]. Only ZF (per result) and cleared CF/OF are defined.
+    /// </summary>
+    public static ulong Bextr(ulong src, ulong control, GprOperandSize size, ref uint eflags)
+    {
+        var bits = WidthBits(size);
+        var start = (int)(control & 0xFF);
+        var length = (int)((control >> 8) & 0xFF);
+
+        ulong result;
+        if (start >= bits)
+        {
+            result = 0;
+        }
+        else
+        {
+            var shifted = (src & WidthMask(size)) >> start;
+            if (length == 0)
+            {
+                result = 0;
+            }
+            else if (length >= bits)
+            {
+                result = shifted;
+            }
+            else
+            {
+                result = shifted & ((1UL << length) - 1);
+            }
+        }
+
+        result &= WidthMask(size);
+        eflags = WithFlag(eflags, FlagZero, result == 0);
+        eflags = WithFlag(eflags, FlagCarry, false);
+        eflags = WithFlag(eflags, FlagOverflow, false);
+        return result;
+    }
+
+    /// <summary>
+    /// BZHI: zero the bits of <paramref name="src"/> from bit position <c>index[7:0]</c> upward.
+    /// CF is set when the requested position is at or beyond the operand width.
+    /// </summary>
+    public static ulong Bzhi(ulong src, ulong index, GprOperandSize size, ref uint eflags)
+    {
+        var bits = WidthBits(size);
+        var mask = WidthMask(size);
+        var s = src & mask;
+        var n = (int)(index & 0xFF);
+
+        ulong result;
+        bool carry;
+        if (n >= bits)
+        {
+            result = s;
+            carry = true;
+        }
+        else
+        {
+            result = s & ((1UL << n) - 1);
+            carry = false;
+        }
+
+        eflags = ApplyLogicFlags(eflags, result, size, carry);
+        return result;
+    }
+
+    /// <summary>TZCNT: count trailing zero bits. If src == 0 the result is the operand width and CF is set.</summary>
+    public static ulong Tzcnt(ulong src, GprOperandSize size, ref uint eflags)
+    {
+        var bits = WidthBits(size);
+        var s = src & WidthMask(size);
+
+        ulong result;
+        bool carry;
+        if (s == 0)
+        {
+            result = (ulong)bits;
+            carry = true;
+        }
+        else
+        {
+            result = (ulong)(size == GprOperandSize.Bits64
+                ? BitOperations.TrailingZeroCount(s)
+                : BitOperations.TrailingZeroCount((uint)s));
+            carry = false;
+        }
+
+        eflags = WithFlag(eflags, FlagCarry, carry);
+        eflags = WithFlag(eflags, FlagZero, result == 0);
+        return result;
+    }
+
+    /// <summary>LZCNT: count leading zero bits. If src == 0 the result is the operand width and CF is set.</summary>
+    public static ulong Lzcnt(ulong src, GprOperandSize size, ref uint eflags)
+    {
+        var bits = WidthBits(size);
+        var s = src & WidthMask(size);
+
+        ulong result;
+        bool carry;
+        if (s == 0)
+        {
+            result = (ulong)bits;
+            carry = true;
+        }
+        else
+        {
+            result = (ulong)(size == GprOperandSize.Bits64
+                ? BitOperations.LeadingZeroCount(s)
+                : BitOperations.LeadingZeroCount((uint)s));
+            carry = false;
+        }
+
+        eflags = WithFlag(eflags, FlagCarry, carry);
+        eflags = WithFlag(eflags, FlagZero, result == 0);
+        return result;
+    }
+
+    /// <summary>RORX: rotate <paramref name="src"/> right by <paramref name="count"/> (masked to the operand width). No flags.</summary>
+    public static ulong Rorx(ulong src, int count, GprOperandSize size)
+    {
+        var bits = WidthBits(size);
+        var mask = WidthMask(size);
+        var s = src & mask;
+        var rotate = count & (bits - 1);
+        if (rotate == 0)
+        {
+            return s;
+        }
+
+        return ((s >> rotate) | (s << (bits - rotate))) & mask;
+    }
+
+    /// <summary>SARX: arithmetic shift right by <paramref name="count"/> (masked to the operand width). No flags.</summary>
+    public static ulong Sarx(ulong src, int count, GprOperandSize size)
+    {
+        var bits = WidthBits(size);
+        var mask = WidthMask(size);
+        var shift = count & (bits - 1);
+        if (size == GprOperandSize.Bits64)
+        {
+            return (ulong)((long)src >> shift);
+        }
+
+        return (ulong)(uint)((int)(uint)src >> shift) & mask;
+    }
+
+    /// <summary>SHLX: logical shift left by <paramref name="count"/> (masked to the operand width). No flags.</summary>
+    public static ulong Shlx(ulong src, int count, GprOperandSize size)
+    {
+        var bits = WidthBits(size);
+        var mask = WidthMask(size);
+        var shift = count & (bits - 1);
+        return (src << shift) & mask;
+    }
+
+    /// <summary>SHRX: logical shift right by <paramref name="count"/> (masked to the operand width). No flags.</summary>
+    public static ulong Shrx(ulong src, int count, GprOperandSize size)
+    {
+        var bits = WidthBits(size);
+        var mask = WidthMask(size);
+        var s = src & mask;
+        var shift = count & (bits - 1);
+        return s >> shift;
+    }
+
+    /// <summary>PDEP: deposit contiguous low bits of <paramref name="src"/> into the positions selected by <paramref name="mask"/>. No flags.</summary>
+    public static ulong Pdep(ulong src, ulong mask, GprOperandSize size)
+    {
+        var bits = WidthBits(size);
+        var selector = mask & WidthMask(size);
+        ulong result = 0;
+        var bit = 0;
+        for (var i = 0; i < bits; i++)
+        {
+            var position = 1UL << i;
+            if ((selector & position) != 0)
+            {
+                if (((src >> bit) & 1UL) != 0)
+                {
+                    result |= position;
+                }
+
+                bit++;
+            }
+        }
+
+        return result & WidthMask(size);
+    }
+
+    /// <summary>PEXT: gather the bits of <paramref name="src"/> selected by <paramref name="mask"/> into contiguous low bits. No flags.</summary>
+    public static ulong Pext(ulong src, ulong mask, GprOperandSize size)
+    {
+        var bits = WidthBits(size);
+        var selector = mask & WidthMask(size);
+        ulong result = 0;
+        var bit = 0;
+        for (var i = 0; i < bits; i++)
+        {
+            if ((selector & (1UL << i)) != 0)
+            {
+                if (((src >> i) & 1UL) != 0)
+                {
+                    result |= 1UL << bit;
+                }
+
+                bit++;
+            }
+        }
+
+        return result & WidthMask(size);
+    }
+}

src/SharpEmu.Core/Cpu/Emulation/GprOperandSize.cs

@@ -0,0 +1,14 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+namespace SharpEmu.Core.Cpu.Emulation;
+
+/// <summary>
+/// Operand width for the emulated general-purpose-register instructions. The numeric value is the
+/// bit width, so it can double as the "count leading/trailing zeros of an all-zero source" result.
+/// </summary>
+public enum GprOperandSize
+{
+    Bits32 = 32,
+    Bits64 = 64,
+}

src/SharpEmu.Core/Cpu/Native/DirectExecutionBackend.Exceptions.cs

@@ -128,6 +128,11 @@ public sealed partial class DirectExecutionBackend
 			{
 				return -1;
 			}
+			if (exceptionCode == StatusIllegalInstruction &&
+				TryRecoverIllegalInstruction(contextRecord, rip))
+			{
+				return -1;
+			}
 			if (IsBenignHostDebugException(exceptionCode))
 			{
 				return -1;

src/SharpEmu.Core/Cpu/Native/DirectExecutionBackend.IllegalInstruction.cs

@@ -0,0 +1,362 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Buffers.Binary;
+using System.Threading;
+using Iced.Intel;
+using SharpEmu.Core.Cpu.Emulation;
+
+namespace SharpEmu.Core.Cpu.Native;
+
+// Software fallback for the BMI1/BMI2/ABM general-purpose-register instructions.
+//
+// Guest code runs natively, so the guest and host share the same virtual address space and the
+// same registers (the OS delivers them in the CONTEXT record on a fault). When the host CPU lacks
+// one of these extensions it raises #UD instead of executing the opcode; without this the title
+// simply aborts. Here we decode the faulting instruction, evaluate it against the trapped register
+// and memory state, write the result back into the CONTEXT, step RIP past the instruction and ask
+// the OS to continue. Only the register-only BMI/ABM forms are handled; anything else returns false
+// and falls through to the existing diagnostics unchanged, so this can never mis-handle an opcode it
+// does not fully model.
+public sealed partial class DirectExecutionBackend
+{
+    // Windows x64 CONTEXT.EFlags lives just past the segment selectors. The GPR offsets it shares
+    // with the rest of the backend are the CTX_* constants declared in DirectExecutionBackend.cs.
+    private const int CTX_EFLAGS = 68;
+
+    // STATUS_ILLEGAL_INSTRUCTION (#UD surfaced by the Windows vectored handler).
+    private const uint StatusIllegalInstruction = 0xC000001Du;
+
+    private const int MaxInstructionBytes = 15;
+
+    // Instruction-window sizes tried in turn so a fault near a page boundary still decodes.
+    private static readonly int[] DecodeWindowSizes = { MaxInstructionBytes, 11, 8, 4, 2 };
+
+    private static int _bmiSoftwareFallbackAnnounced;
+    private static long _bmiInstructionsEmulated;
+
+    private unsafe bool TryRecoverIllegalInstruction(void* contextRecord, ulong rip)
+    {
+        if (!TryReadFaultingInstruction(rip, out var instruction))
+        {
+            return false;
+        }
+
+        if (instruction.Op0Kind != OpKind.Register ||
+            !TryGetGprSlot(instruction.Op0Register, out var destOffset, out var size))
+        {
+            return false;
+        }
+
+        if (!TryEvaluate(contextRecord, in instruction, size, out var result, out var flagsChanged, out var eflags))
+        {
+            return false;
+        }
+
+        WriteCtxU64(contextRecord, destOffset, result);
+        if (flagsChanged)
+        {
+            WriteCtxU32(contextRecord, CTX_EFLAGS, eflags);
+        }
+
+        WriteCtxU64(contextRecord, CTX_RIP, rip + (ulong)instruction.Length);
+
+        Interlocked.Increment(ref _bmiInstructionsEmulated);
+        if (Interlocked.Exchange(ref _bmiSoftwareFallbackAnnounced, 1) == 0)
+        {
+            Console.Error.WriteLine(
+                "[LOADER][INFO] Host lacks a BMI/ABM extension used by the guest; " +
+                "emulating those instructions in software.");
+        }
+
+        return true;
+    }
+
+    private unsafe bool TryEvaluate(
+        void* contextRecord,
+        in Instruction instruction,
+        GprOperandSize size,
+        out ulong result,
+        out bool flagsChanged,
+        out uint eflags)
+    {
+        result = 0;
+        flagsChanged = false;
+        eflags = ReadCtxU32(contextRecord, CTX_EFLAGS);
+
+        switch (instruction.Mnemonic)
+        {
+            case Mnemonic.Andn:
+                if (!TryReadOperand(contextRecord, in instruction, 1, size, out var andnSrc1) ||
+                    !TryReadOperand(contextRecord, in instruction, 2, size, out var andnSrc2))
+                {
+                    return false;
+                }
+
+                result = BmiInstructionEmulator.Andn(andnSrc1, andnSrc2, size, ref eflags);
+                flagsChanged = true;
+                return true;
+
+            case Mnemonic.Blsi:
+            case Mnemonic.Blsmsk:
+            case Mnemonic.Blsr:
+                if (!TryReadOperand(contextRecord, in instruction, 1, size, out var blsSrc))
+                {
+                    return false;
+                }
+
+                result = instruction.Mnemonic switch
+                {
+                    Mnemonic.Blsi => BmiInstructionEmulator.Blsi(blsSrc, size, ref eflags),
+                    Mnemonic.Blsmsk => BmiInstructionEmulator.Blsmsk(blsSrc, size, ref eflags),
+                    _ => BmiInstructionEmulator.Blsr(blsSrc, size, ref eflags),
+                };
+                flagsChanged = true;
+                return true;
+
+            case Mnemonic.Bextr:
+                if (!TryReadOperand(contextRecord, in instruction, 1, size, out var bextrSrc) ||
+                    !TryReadOperand(contextRecord, in instruction, 2, size, out var bextrControl))
+                {
+                    return false;
+                }
+
+                result = BmiInstructionEmulator.Bextr(bextrSrc, bextrControl, size, ref eflags);
+                flagsChanged = true;
+                return true;
+
+            case Mnemonic.Bzhi:
+                if (!TryReadOperand(contextRecord, in instruction, 1, size, out var bzhiSrc) ||
+                    !TryReadOperand(contextRecord, in instruction, 2, size, out var bzhiIndex))
+                {
+                    return false;
+                }
+
+                result = BmiInstructionEmulator.Bzhi(bzhiSrc, bzhiIndex, size, ref eflags);
+                flagsChanged = true;
+                return true;
+
+            case Mnemonic.Tzcnt:
+            case Mnemonic.Lzcnt:
+                if (!TryReadOperand(contextRecord, in instruction, 1, size, out var cntSrc))
+                {
+                    return false;
+                }
+
+                result = instruction.Mnemonic == Mnemonic.Tzcnt
+                    ? BmiInstructionEmulator.Tzcnt(cntSrc, size, ref eflags)
+                    : BmiInstructionEmulator.Lzcnt(cntSrc, size, ref eflags);
+                flagsChanged = true;
+                return true;
+
+            case Mnemonic.Rorx:
+                if (instruction.Op2Kind != OpKind.Immediate8 ||
+                    !TryReadOperand(contextRecord, in instruction, 1, size, out var rorxSrc))
+                {
+                    return false;
+                }
+
+                result = BmiInstructionEmulator.Rorx(rorxSrc, instruction.Immediate8, size);
+                return true;
+
+            case Mnemonic.Sarx:
+            case Mnemonic.Shlx:
+            case Mnemonic.Shrx:
+                if (!TryReadOperand(contextRecord, in instruction, 1, size, out var shiftSrc) ||
+                    !TryReadOperand(contextRecord, in instruction, 2, size, out var shiftCount))
+                {
+                    return false;
+                }
+
+                result = instruction.Mnemonic switch
+                {
+                    Mnemonic.Sarx => BmiInstructionEmulator.Sarx(shiftSrc, (int)shiftCount, size),
+                    Mnemonic.Shlx => BmiInstructionEmulator.Shlx(shiftSrc, (int)shiftCount, size),
+                    _ => BmiInstructionEmulator.Shrx(shiftSrc, (int)shiftCount, size),
+                };
+                return true;
+
+            case Mnemonic.Pdep:
+            case Mnemonic.Pext:
+                if (!TryReadOperand(contextRecord, in instruction, 1, size, out var packSrc) ||
+                    !TryReadOperand(contextRecord, in instruction, 2, size, out var packMask))
+                {
+                    return false;
+                }
+
+                result = instruction.Mnemonic == Mnemonic.Pdep
+                    ? BmiInstructionEmulator.Pdep(packSrc, packMask, size)
+                    : BmiInstructionEmulator.Pext(packSrc, packMask, size);
+                return true;
+
+            default:
+                return false;
+        }
+    }
+
+    private unsafe bool TryReadFaultingInstruction(ulong rip, out Instruction instruction)
+    {
+        // Try the full instruction window first, then shrink so a fault near the end of a mapped
+        // page (where fewer than 15 bytes are readable) still decodes.
+        foreach (var attempt in DecodeWindowSizes)
+        {
+            var buffer = new byte[attempt];
+            if (!TryReadHostBytes(rip, buffer))
+            {
+                continue;
+            }
+
+            var decoder = Decoder.Create(64, new ByteArrayCodeReader(buffer));
+            decoder.IP = rip;
+            decoder.Decode(out instruction);
+            if (instruction.Code != Code.INVALID && instruction.Length > 0 && instruction.Length <= attempt)
+            {
+                return true;
+            }
+        }
+
+        instruction = default;
+        return false;
+    }
+
+    private unsafe bool TryReadOperand(
+        void* contextRecord,
+        in Instruction instruction,
+        int operandIndex,
+        GprOperandSize size,
+        out ulong value)
+    {
+        value = 0;
+        switch (instruction.GetOpKind(operandIndex))
+        {
+            case OpKind.Register:
+                if (!TryGetGprSlot(instruction.GetOpRegister(operandIndex), out var offset, out _))
+                {
+                    return false;
+                }
+
+                var raw = ReadCtxU64(contextRecord, offset);
+                value = size == GprOperandSize.Bits64 ? raw : raw & 0xFFFF_FFFFUL;
+                return true;
+
+            case OpKind.Memory:
+                if (!TryComputeMemoryAddress(contextRecord, in instruction, out var address))
+                {
+                    return false;
+                }
+
+                var byteCount = size == GprOperandSize.Bits64 ? 8 : 4;
+                var buffer = new byte[byteCount];
+                if (!TryReadHostBytes(address, buffer))
+                {
+                    return false;
+                }
+
+                value = byteCount == 8
+                    ? BinaryPrimitives.ReadUInt64LittleEndian(buffer)
+                    : BinaryPrimitives.ReadUInt32LittleEndian(buffer);
+                return true;
+
+            default:
+                return false;
+        }
+    }
+
+    private unsafe bool TryComputeMemoryAddress(void* contextRecord, in Instruction instruction, out ulong address)
+    {
+        address = 0;
+
+        // FS/GS-relative operands need the guest segment base, which is not modelled here.
+        if (instruction.SegmentPrefix != Register.None)
+        {
+            return false;
+        }
+
+        if (instruction.IsIPRelativeMemoryOperand)
+        {
+            address = instruction.IPRelativeMemoryAddress;
+            return true;
+        }
+
+        var effective = instruction.MemoryDisplacement64;
+        if (instruction.MemoryBase != Register.None)
+        {
+            if (!TryGetGpr64Offset(instruction.MemoryBase, out var baseOffset))
+            {
+                return false;
+            }
+
+            effective += ReadCtxU64(contextRecord, baseOffset);
+        }
+
+        if (instruction.MemoryIndex != Register.None)
+        {
+            if (!TryGetGpr64Offset(instruction.MemoryIndex, out var indexOffset))
+            {
+                return false;
+            }
+
+            effective += ReadCtxU64(contextRecord, indexOffset) * (ulong)instruction.MemoryIndexScale;
+        }
+
+        address = effective;
+        return true;
+    }
+
+    // Maps a 32- or 64-bit GPR to its CONTEXT offset and reports the operand width it implies.
+    private static bool TryGetGprSlot(Register register, out int offset, out GprOperandSize size)
+    {
+        switch (register)
+        {
+            case Register.EAX: offset = CTX_RAX; size = GprOperandSize.Bits32; return true;
+            case Register.ECX: offset = CTX_RCX; size = GprOperandSize.Bits32; return true;
+            case Register.EDX: offset = CTX_RDX; size = GprOperandSize.Bits32; return true;
+            case Register.EBX: offset = CTX_RBX; size = GprOperandSize.Bits32; return true;
+            case Register.ESP: offset = CTX_RSP; size = GprOperandSize.Bits32; return true;
+            case Register.EBP: offset = CTX_RBP; size = GprOperandSize.Bits32; return true;
+            case Register.ESI: offset = CTX_RSI; size = GprOperandSize.Bits32; return true;
+            case Register.EDI: offset = CTX_RDI; size = GprOperandSize.Bits32; return true;
+            case Register.R8D: offset = CTX_R8; size = GprOperandSize.Bits32; return true;
+            case Register.R9D: offset = CTX_R9; size = GprOperandSize.Bits32; return true;
+            case Register.R10D: offset = CTX_R10; size = GprOperandSize.Bits32; return true;
+            case Register.R11D: offset = CTX_R11; size = GprOperandSize.Bits32; return true;
+            case Register.R12D: offset = CTX_R12; size = GprOperandSize.Bits32; return true;
+            case Register.R13D: offset = CTX_R13; size = GprOperandSize.Bits32; return true;
+            case Register.R14D: offset = CTX_R14; size = GprOperandSize.Bits32; return true;
+            case Register.R15D: offset = CTX_R15; size = GprOperandSize.Bits32; return true;
+            default:
+                if (TryGetGpr64Offset(register, out offset))
+                {
+                    size = GprOperandSize.Bits64;
+                    return true;
+                }
+
+                size = GprOperandSize.Bits32;
+                return false;
+        }
+    }
+
+    private static bool TryGetGpr64Offset(Register register, out int offset)
+    {
+        switch (register)
+        {
+            case Register.RAX: offset = CTX_RAX; return true;
+            case Register.RCX: offset = CTX_RCX; return true;
+            case Register.RDX: offset = CTX_RDX; return true;
+            case Register.RBX: offset = CTX_RBX; return true;
+            case Register.RSP: offset = CTX_RSP; return true;
+            case Register.RBP: offset = CTX_RBP; return true;
+            case Register.RSI: offset = CTX_RSI; return true;
+            case Register.RDI: offset = CTX_RDI; return true;
+            case Register.R8: offset = CTX_R8; return true;
+            case Register.R9: offset = CTX_R9; return true;
+            case Register.R10: offset = CTX_R10; return true;
+            case Register.R11: offset = CTX_R11; return true;
+            case Register.R12: offset = CTX_R12; return true;
+            case Register.R13: offset = CTX_R13; return true;
+            case Register.R14: offset = CTX_R14; return true;
+            case Register.R15: offset = CTX_R15; return true;
+            default: offset = 0; return false;
+        }
+    }
+}

src/SharpEmu.Core/Cpu/Native/DirectExecutionBackend.Imports.cs

@@ -598,7 +598,7 @@ public sealed partial class DirectExecutionBackend
 				}
 
 				*(ulong*)(argPackPtr + 96) = unchecked((ulong)transferStub);
-				if (string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_FIBER"), "1", StringComparison.Ordinal))
+				if (_logFiber)
 				{
 					Console.Error.WriteLine(
 						$"[LOADER][TRACE] fiber.context-transfer rip=0x{transferTarget.Rip:X16} " +
@@ -1292,7 +1292,7 @@ public sealed partial class DirectExecutionBackend
 		}
 
 		int returnValue;
-		if (IsNoBlockLeafImport(importStubEntry.Nid))
+		if (importStubEntry.IsNoBlockLeaf)
 		{
 			cpuContext.ClearRaxWriteFlag();
 			returnValue = export.Function(cpuContext);

src/SharpEmu.Core/Cpu/Native/DirectExecutionBackend.cs

@@ -48,6 +48,8 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 		// hashing are hoisted to stub-setup time.
 		public bool IsLeaf { get; }
 
+		public bool IsNoBlockLeaf { get; }
+
 		public bool SuppressStrlenTrace { get; }
 
 		public bool IsLoopGuardBoundary { get; }
@@ -59,6 +61,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			string nid,
 			ExportedFunction? export,
 			bool isLeaf,
+			bool isNoBlockLeaf,
 			bool suppressStrlenTrace,
 			bool isLoopGuardBoundary,
 			ulong nidHash)
@@ -67,6 +70,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 			Nid = nid;
 			Export = export;
 			IsLeaf = isLeaf;
+			IsNoBlockLeaf = isNoBlockLeaf;
 			SuppressStrlenTrace = suppressStrlenTrace;
 			IsLoopGuardBoundary = isLoopGuardBoundary;
 			NidHash = nidHash;
@@ -318,6 +322,8 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 
 	private bool _logUsleep;
 
+	private bool _logFiber;
+
 	private bool _logBootstrap;
 
 	private bool _logAllImports;
@@ -1067,6 +1073,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 		_ignoredGuestInt41Count = 0;
 		_logGuestThreads = string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_GUEST_THREADS"), "1", StringComparison.Ordinal);
 		_logUsleep = string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_USLEEP"), "1", StringComparison.Ordinal);
+		_logFiber = string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_FIBER"), "1", StringComparison.Ordinal);
 		_logBootstrap = string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_BOOTSTRAP"), "1", StringComparison.Ordinal);
 		_logAllImports = string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_ALL_IMPORTS"), "1", StringComparison.Ordinal);
 		_logImportFrames = string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_IMPORT_FRAMES"), "1", StringComparison.Ordinal);
@@ -1164,6 +1171,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 				text2,
 				resolvedExport,
 				IsLeafImport(text2),
+				IsNoBlockLeafImport(text2),
 				ShouldSuppressStrlenTrace(text2),
 				IsImportLoopGuardBoundary(text2),
 				StableHash64(text2));
@@ -1760,14 +1768,16 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 		frameAddress = 0;
 		transferStub = 0;
 		error = null;
-		if (target.Rip < 65536 || target.Rsp == 0)
+		if (ActiveCpuContext is not { } activeContext)
 		{
-			error = $"invalid guest context transfer target rip=0x{target.Rip:X16} rsp=0x{target.Rsp:X16}";
+			error = "guest context transfer without an active CPU context";
 			return false;
 		}
-		if (target.Rsp < sizeof(ulong) ||
-			ActiveCpuContext is not { } activeContext ||
-			!activeContext.TryWriteUInt64(target.Rsp - sizeof(ulong), target.Rip))
+		if (!TryValidateGuestContextTransferTarget(activeContext.Memory, target, out error))
+		{
+			return false;
+		}
+		if (!activeContext.TryWriteUInt64(target.Rsp - sizeof(ulong), target.Rip))
 		{
 			error = $"guest context transfer slot is not writable at 0x{target.Rsp - sizeof(ulong):X16}";
 			return false;
@@ -1811,6 +1821,30 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 		return true;
 	}
 
+	internal static bool TryValidateGuestContextTransferTarget(
+		ICpuMemory memory,
+		in GuestCpuContinuation target,
+		out string? error)
+	{
+		if (target.Rip < 65536 || target.Rsp < sizeof(ulong))
+		{
+			error = $"invalid guest context transfer target rip=0x{target.Rip:X16} rsp=0x{target.Rsp:X16}";
+			return false;
+		}
+
+		Span<byte> ripProbe = stackalloc byte[1];
+		if (!memory.TryRead(target.Rip, ripProbe))
+		{
+			error =
+				$"guest context transfer target rip=0x{target.Rip:X16} is not mapped guest memory " +
+				$"(rsp=0x{target.Rsp:X16})";
+			return false;
+		}
+
+		error = null;
+		return true;
+	}
+
 	private unsafe nint GetOrCreateGuestContextTransferStub()
 	{
 		if (Volatile.Read(ref _guestContextTransferStub) != 0)
@@ -3264,31 +3298,15 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 		{
 			Pump(callerContext, reason);
 
-			var threads = SnapshotGuestThreads();
-			if (threads.Length == 0)
+			// Tally run states under the lock without allocating a snapshot every
+			// spin (this loop can iterate rapidly); the full snapshot is only
+			// materialized for the gated diagnostic dump below.
+			GetGuestThreadActivity(out var threadCount, out var hasReadyThread, out var hasRunningThread, out var hasBlockedThread);
+			if (threadCount == 0)
 			{
 				return;
 			}
 
-			var hasReadyThread = false;
-			var hasRunningThread = false;
-			var hasBlockedThread = false;
-			foreach (var thread in threads)
-			{
-				switch (thread.State)
-				{
-					case GuestThreadRunState.Ready:
-						hasReadyThread = true;
-						break;
-					case GuestThreadRunState.Running:
-						hasRunningThread = true;
-						break;
-					case GuestThreadRunState.Blocked:
-						hasBlockedThread = true;
-						break;
-				}
-			}
-
 			if (hasReadyThread)
 			{
 				continue;
@@ -3301,7 +3319,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 
 			if (_logGuestThreads && Stopwatch.GetTimestamp() >= nextSnapshotTimestamp)
 			{
-				foreach (var thread in threads)
+				foreach (var thread in SnapshotGuestThreads())
 				{
 					Console.Error.WriteLine(
 						$"[LOADER][TRACE] guest_thread.idle_wait reason={reason} handle=0x{thread.ThreadHandle:X16} " +
@@ -3321,7 +3339,36 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
 	{
 		using (LockGate("SnapshotGuestThreads"))
 		{
-			return _guestThreads.Values.ToArray();
+			var snapshot = new GuestThreadState[_guestThreads.Count];
+			_guestThreads.Values.CopyTo(snapshot, 0);
+			return snapshot;
+		}
+	}
+
+	// Allocation-free run-state tally for the idle spin loop.
+	private void GetGuestThreadActivity(out int count, out bool hasReady, out bool hasRunning, out bool hasBlocked)
+	{
+		hasReady = false;
+		hasRunning = false;
+		hasBlocked = false;
+		using (LockGate("GetGuestThreadActivity"))
+		{
+			count = _guestThreads.Count;
+			foreach (var thread in _guestThreads.Values)
+			{
+				switch (thread.State)
+				{
+					case GuestThreadRunState.Ready:
+						hasReady = true;
+						break;
+					case GuestThreadRunState.Running:
+						hasRunning = true;
+						break;
+					case GuestThreadRunState.Blocked:
+						hasBlocked = true;
+						break;
+				}
+			}
 		}
 	}
 

src/SharpEmu.Core/Memory/PhysicalVirtualMemory.cs

@@ -349,10 +349,8 @@ public sealed unsafe class PhysicalVirtualMemory : IVirtualMemory, IGuestMemoryA
         var requestedCursor = AlignUp(desiredAddress, effectiveAlignment);
         var cursor = GetAllocationSearchCursor(desiredAddress, requestedCursor, effectiveAlignment, executable);
 
-        // POSIX treats the requested address as a hint, and Rosetta may
-        // relocate whole guest windows. Over-allocate once so the returned
-        // host range always contains an aligned guest-visible start.
-        if (!OperatingSystem.IsWindows())
+        // macOS needs alignment over-allocation; Linux uses exact-address search.
+        if (OperatingSystem.IsMacOS())
         {
             var reserveSize = effectiveAlignment > PageSize
                 ? alignedSize + effectiveAlignment

src/SharpEmu.Core/Runtime/SharpEmuRuntime.cs

@@ -12,6 +12,7 @@ using SharpEmu.Libs.Kernel;
 using SharpEmu.Libs.AppContent;
 using SharpEmu.Libs.SaveData;
 using SharpEmu.Libs.Fiber;
+using SharpEmu.Libs.SystemService;
 using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.Linq;
@@ -141,6 +142,7 @@ public sealed class SharpEmuRuntime : ISharpEmuRuntime
         var image = LoadImage(normalizedEbootPath);
         VideoOutExports.ConfigureApplicationInfo(image.Title, image.TitleId, image.Version);
         SaveDataExports.ConfigureApplicationInfo(image.TitleId);
+        SystemServiceExports.ConfigureApplicationInfo(image.TitleId);
         _ = RegisterLoadedModule(normalizedEbootPath, image, isMain: true, isSystemModule: false);
         KernelRuntimeCompatExports.ConfigureProcessProcParamAddress(image.ProcParamAddress);
         Console.Error.WriteLine($"[RUNTIME] Entry: 0x{image.EntryPoint:X16}");

src/SharpEmu.Core/SharpEmu.Core.csproj

@@ -14,6 +14,10 @@ SPDX-License-Identifier: GPL-2.0-or-later
     <PackageReference Include="Iced" />
   </ItemGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="SharpEmu.Libs.Tests" />
+  </ItemGroup>
+
   <PropertyGroup>
     <NoWarn>$(NoWarn);1591</NoWarn>
   </PropertyGroup>

src/SharpEmu.GUI/GuiSettings.cs

@@ -48,6 +48,8 @@ public sealed class GuiSettings
     /// <summary>Publish launcher/game status to Discord Rich Presence.</summary>
     public bool DiscordRichPresence { get; set; } = true;
 
+    public bool CheckForUpdatesOnStartup { get; set; } = true;
+
     /// <summary>Names of SHARPEMU_* switches set to "1" in the emulator's environment at launch.</summary>
     public List<string> EnvironmentToggles { get; set; } = new();
 

src/SharpEmu.GUI/Languages/en.json

@@ -31,9 +31,11 @@
   "Options.Env.Desc": "Switches passed to the emulator as environment variables at launch.",
   "Options.Env.Bthid.Desc": "Report Bluetooth HID as unavailable for titles whose wheel/FFB middleware polls forever.\nLeave off normally. Some titles freeze when init fails.",
   "Options.Env.LoopGuard.Desc": "Do not force quit titles that repeat the same call for too long.\nTry this when a game exits on its own while loading.",
+  "Options.Env.WritableApp0.Desc": "Allow titles to create and write files inside their install folder.\nNeeded by unpackaged dumps that write their save or config data under /app0.",
   "Options.Env.VkValidation.Desc": "Enable Vulkan validation layers for GPU debugging.\nSlow. Requires the Vulkan SDK to be installed.",
   "Options.Env.DumpSpirv.Desc": "Dump AGC shaders and their SPIR-V translations to the shader-dumps folder.\nUse when reporting shader or rendering bugs.",
   "Options.Env.LogDirectMemory.Desc": "Log direct memory allocations and failures to the console.\nUse when a game aborts or exits during boot.",
+  "Options.Env.LogIo.Desc": "Log file open, read, and path-resolve activity to the console.\nUse when a game cannot find its data files during boot.",
   "Options.Env.LogNp.Desc": "Log NP (PlayStation Network) library calls to the console.",
   "Options.Section.Emulation": "EMULATION",
   "Options.Section.Logging": "LOGGING",
@@ -142,5 +144,20 @@
   "About.Discord.Label": "Discord",
   "About.Discord.Desc": "Join the community, get support and follow development.",
   "About.GithubButton": "Contribute in GitHub!",
-  "About.DiscordButton": "Join our Discord!"
+  "About.DiscordButton": "Join our Discord!",
+
+  "Updater.Auto.Label": "Check for updates on startup",
+  "Updater.Auto.Desc": "Checks GitHub without delaying startup.",
+  "Updater.Label": "Updates",
+  "Updater.Check": "Check for updates",
+  "Updater.DownloadRestart": "Download and restart",
+  "Updater.Status.Ready": "Current build: {0}",
+  "Updater.Status.Checking": "Checking for updates…",
+  "Updater.Status.Current": "You are up to date ({0}).",
+  "Updater.Status.Available": "A new build is available: {0}",
+  "Updater.Status.Downloading": "Downloading update… {0}%",
+  "Updater.Status.Installing": "Installing update…",
+  "Updater.Status.Timeout": "Update check timed out after 10 seconds.",
+  "Updater.Status.Failed": "Could not check for updates.",
+  "Updater.Status.Unsupported": "Automatic updating requires a Windows, Linux or macOS x64 build."
 }

src/SharpEmu.GUI/Languages/tr.json

@@ -125,5 +125,20 @@
   "Dialog.PsExecutables": "PS çalıştırılabilirleri",
   "Dialog.SaveLogFile": "Günlük dosyasının kaydedileceği yeri seçin",
   "Dialog.PlainTextFiles": "Düz Metin Dosyaları",
-  "Dialog.LogFiles": "Günlük Dosyaları"
+  "Dialog.LogFiles": "Günlük Dosyaları",
+
+  "Updater.Auto.Label": "Açılışta güncellemeleri denetle",
+  "Updater.Auto.Desc": "Açılışı geciktirmeden GitHub'ı denetler.",
+  "Updater.Label": "Güncellemeler",
+  "Updater.Check": "Güncellemeleri denetle",
+  "Updater.DownloadRestart": "İndir ve yeniden başlat",
+  "Updater.Status.Ready": "Mevcut build: {0}",
+  "Updater.Status.Checking": "Güncellemeler denetleniyor…",
+  "Updater.Status.Current": "Güncelsiniz ({0}).",
+  "Updater.Status.Available": "Yeni build mevcut: {0}",
+  "Updater.Status.Downloading": "Güncelleme indiriliyor… %{0}",
+  "Updater.Status.Installing": "Güncelleme kuruluyor…",
+  "Updater.Status.Timeout": "Güncelleme denetimi 10 saniye sonra zaman aşımına uğradı.",
+  "Updater.Status.Failed": "Güncellemeler denetlenemedi.",
+  "Updater.Status.Unsupported": "Otomatik güncelleme Windows, Linux veya macOS x64 build'i gerektirir."
 }

src/SharpEmu.GUI/MainWindow.axaml

@@ -315,6 +315,16 @@ SPDX-License-Identifier: GPL-2.0-or-later
                         <ToggleSwitch Grid.Column="1" x:Name="DiscordToggle" OnContent="On" OffContent="Off"
                                       VerticalAlignment="Center" />
                       </Grid>
+
+                      <Grid ColumnDefinitions="*,Auto">
+                        <StackPanel VerticalAlignment="Center" Spacing="2" Margin="0,0,16,0">
+                          <TextBlock x:Name="AutoUpdateLabel" Text="Check for updates on startup" FontSize="13" />
+                          <TextBlock x:Name="AutoUpdateDesc" Text="Checks GitHub without delaying startup."
+                                     FontSize="11" Foreground="{StaticResource MutedBrush}" TextWrapping="Wrap" />
+                        </StackPanel>
+                        <ToggleSwitch Grid.Column="1" x:Name="AutoUpdateToggle" OnContent="On" OffContent="Off"
+                                      IsChecked="True" VerticalAlignment="Center" />
+                      </Grid>
                     </StackPanel>
                   </Border>
                   <Border Classes="card">
@@ -322,6 +332,16 @@ SPDX-License-Identifier: GPL-2.0-or-later
                       <TextBlock x:Name="AboutSectionTitle"
                                 Classes="sectionTitle"
                                 Text="ABOUT" />
+
+                      <Grid ColumnDefinitions="*,Auto">
+                        <StackPanel Grid.Column="0" Spacing="2" VerticalAlignment="Center">
+                          <TextBlock x:Name="UpdateLabel" Text="Updates" FontSize="13" />
+                          <TextBlock x:Name="UpdateStatusText" Text="Current build: dev" FontSize="11"
+                                     Foreground="{StaticResource MutedBrush}" TextWrapping="Wrap" />
+                        </StackPanel>
+                        <Button Grid.Column="1" x:Name="UpdateButton" Classes="ghost"
+                                Content="Check for updates" VerticalAlignment="Center" />
+                      </Grid>
                       
                       <!--Github-->
                       <Grid ColumnDefinitions="*,Auto">
@@ -420,6 +440,17 @@ SPDX-License-Identifier: GPL-2.0-or-later
                                       VerticalAlignment="Center" />
                       </Grid>
 
+                      <Grid ColumnDefinitions="*,Auto">
+                        <StackPanel VerticalAlignment="Center" Spacing="2" Margin="0,0,16,0">
+                          <TextBlock Text="SHARPEMU_WRITABLE_APP0" FontSize="13" FontFamily="Consolas,monospace" />
+                          <TextBlock x:Name="EnvWritableApp0Desc"
+                                     Text="Allow titles to create and write files inside their install folder.&#10;Needed by unpackaged dumps that write their save or config data under /app0."
+                                     FontSize="11" Foreground="{StaticResource MutedBrush}" TextWrapping="Wrap" />
+                        </StackPanel>
+                        <ToggleSwitch Grid.Column="1" x:Name="EnvWritableApp0Toggle" OnContent="On" OffContent="Off"
+                                      VerticalAlignment="Center" />
+                      </Grid>
+
                       <Grid ColumnDefinitions="*,Auto">
                         <StackPanel VerticalAlignment="Center" Spacing="2" Margin="0,0,16,0">
                           <TextBlock Text="SHARPEMU_VK_VALIDATION" FontSize="13" FontFamily="Consolas,monospace" />
@@ -453,6 +484,17 @@ SPDX-License-Identifier: GPL-2.0-or-later
                                       VerticalAlignment="Center" />
                       </Grid>
 
+                      <Grid ColumnDefinitions="*,Auto">
+                        <StackPanel VerticalAlignment="Center" Spacing="2" Margin="0,0,16,0">
+                          <TextBlock Text="SHARPEMU_LOG_IO" FontSize="13" FontFamily="Consolas,monospace" />
+                          <TextBlock x:Name="EnvLogIoDesc"
+                                     Text="Log file open, read, and path-resolve activity to the console.&#10;Use when a game cannot find its data files during boot."
+                                     FontSize="11" Foreground="{StaticResource MutedBrush}" TextWrapping="Wrap" />
+                        </StackPanel>
+                        <ToggleSwitch Grid.Column="1" x:Name="EnvLogIoToggle" OnContent="On" OffContent="Off"
+                                      VerticalAlignment="Center" />
+                      </Grid>
+
                       <Grid ColumnDefinitions="*,Auto">
                         <StackPanel VerticalAlignment="Center" Spacing="2" Margin="0,0,16,0">
                           <TextBlock Text="SHARPEMU_LOG_NP" FontSize="13" FontFamily="Consolas,monospace" />

src/SharpEmu.GUI/MainWindow.axaml.cs

@@ -57,6 +57,9 @@ public partial class MainWindow : Window
     private bool _isRunning;
     private int _autoScrollTicks;
     private int _activePageIndex;
+    private Updater.UpdateInfo? _availableUpdate;
+    private string _updateStatusKey = "Updater.Status.Ready";
+    private object?[] _updateStatusArgs = [BuildInfo.CommitSha ?? "dev"];
 
     // Discord Rich Presence state.
     private readonly long _launcherStartUnixSeconds = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
@@ -131,17 +134,24 @@ public partial class MainWindow : Window
             _settings.DiscordRichPresence = DiscordToggle.IsChecked == true;
             UpdateDiscordPresence();
         };
+        AutoUpdateToggle.IsCheckedChanged += (_, _) =>
+            _settings.CheckForUpdatesOnStartup = AutoUpdateToggle.IsChecked == true;
+        UpdateButton.Click += async (_, _) => await OnUpdateButtonAsync();
         SelectLogFilePathButton.Click += async (_, _) => await SelectLogFilePathAsync();
         EnvBthidToggle.IsCheckedChanged += (_, _) =>
             SetEnvironmentToggle("SHARPEMU_BTHID_UNAVAILABLE", EnvBthidToggle.IsChecked == true);
         EnvLoopGuardToggle.IsCheckedChanged += (_, _) =>
             SetEnvironmentToggle("SHARPEMU_DISABLE_IMPORT_LOOP_GUARD", EnvLoopGuardToggle.IsChecked == true);
+        EnvWritableApp0Toggle.IsCheckedChanged += (_, _) =>
+            SetEnvironmentToggle("SHARPEMU_WRITABLE_APP0", EnvWritableApp0Toggle.IsChecked == true);
         EnvVkValidationToggle.IsCheckedChanged += (_, _) =>
             SetEnvironmentToggle("SHARPEMU_VK_VALIDATION", EnvVkValidationToggle.IsChecked == true);
         EnvDumpSpirvToggle.IsCheckedChanged += (_, _) =>
             SetEnvironmentToggle("SHARPEMU_DUMP_SPIRV", EnvDumpSpirvToggle.IsChecked == true);
         EnvLogDirectMemoryToggle.IsCheckedChanged += (_, _) =>
             SetEnvironmentToggle("SHARPEMU_LOG_DIRECT_MEMORY", EnvLogDirectMemoryToggle.IsChecked == true);
+        EnvLogIoToggle.IsCheckedChanged += (_, _) =>
+            SetEnvironmentToggle("SHARPEMU_LOG_IO", EnvLogIoToggle.IsChecked == true);
         EnvLogNpToggle.IsCheckedChanged += (_, _) =>
             SetEnvironmentToggle("SHARPEMU_LOG_NP", EnvLogNpToggle.IsChecked == true);
         LanguageBox.SelectionChanged += (_, _) => OnLanguageChanged();
@@ -371,6 +381,10 @@ public partial class MainWindow : Window
         ApplySettingsToControls();
         LocateEmulator();
         UpdateDiscordPresence();
+        if (_settings.CheckForUpdatesOnStartup)
+        {
+            _ = CheckForUpdatesAsync();
+        }
         await RescanLibraryAsync();
     }
 
@@ -427,9 +441,11 @@ public partial class MainWindow : Window
         EnvDesc.Text = loc.Get("Options.Env.Desc");
         EnvBthidDesc.Text = loc.Get("Options.Env.Bthid.Desc");
         EnvLoopGuardDesc.Text = loc.Get("Options.Env.LoopGuard.Desc");
+        EnvWritableApp0Desc.Text = loc.Get("Options.Env.WritableApp0.Desc");
         EnvVkValidationDesc.Text = loc.Get("Options.Env.VkValidation.Desc");
         EnvDumpSpirvDesc.Text = loc.Get("Options.Env.DumpSpirv.Desc");
         EnvLogDirectMemoryDesc.Text = loc.Get("Options.Env.LogDirectMemory.Desc");
+        EnvLogIoDesc.Text = loc.Get("Options.Env.LogIo.Desc");
         EnvLogNpDesc.Text = loc.Get("Options.Env.LogNp.Desc");
         EmulationSectionTitle.Text = loc.Get("Options.Section.Emulation");
         LoggingSectionTitle.Text = loc.Get("Options.Section.Logging");
@@ -472,8 +488,10 @@ public partial class MainWindow : Window
 
         DiscordLabel.Text = loc.Get("Options.Discord.Label");
         DiscordDesc.Text = loc.Get("Options.Discord.Desc");
+        AutoUpdateLabel.Text = loc.Get("Updater.Auto.Label");
+        AutoUpdateDesc.Text = loc.Get("Updater.Auto.Desc");
 
-        foreach (var toggle in new[] { StrictToggle, LogToFileToggle, OverrideLogFileToggle, TitleMusicToggle, DiscordToggle })
+        foreach (var toggle in new[] { StrictToggle, LogToFileToggle, OverrideLogFileToggle, TitleMusicToggle, DiscordToggle, AutoUpdateToggle })
         {
             toggle.OnContent = loc.Get("Common.On");
             toggle.OffContent = loc.Get("Common.Off");
@@ -497,6 +515,8 @@ public partial class MainWindow : Window
         DiscordServerDesc.Text = loc.Get("About.Discord.Desc");
         GithubButton.Content = loc.Get("About.GithubButton");
         DiscordButton.Content = loc.Get("About.DiscordButton");
+        UpdateLabel.Text = loc.Get("Updater.Label");
+        RefreshUpdateText();
 
         UpdateEmptyStateTexts();
         UpdateSelectedGameTexts();
@@ -612,15 +632,87 @@ public partial class MainWindow : Window
         OverrideLogFileToggle.IsChecked = _settings.OverrideLogFile;
         TitleMusicToggle.IsChecked = _settings.PlayTitleMusic;
         DiscordToggle.IsChecked = _settings.DiscordRichPresence;
+        AutoUpdateToggle.IsChecked = _settings.CheckForUpdatesOnStartup;
         EnvBthidToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_BTHID_UNAVAILABLE");
         EnvLoopGuardToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_DISABLE_IMPORT_LOOP_GUARD");
+        EnvWritableApp0Toggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_WRITABLE_APP0");
         EnvVkValidationToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_VK_VALIDATION");
         EnvDumpSpirvToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_DUMP_SPIRV");
         EnvLogDirectMemoryToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_LOG_DIRECT_MEMORY");
+        EnvLogIoToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_LOG_IO");
         EnvLogNpToggle.IsChecked = _settings.EnvironmentToggles.Contains("SHARPEMU_LOG_NP");
         UpdateLogFilePathText();
     }
 
+    private async Task OnUpdateButtonAsync()
+    {
+        if (_availableUpdate is null)
+        {
+            await CheckForUpdatesAsync();
+            return;
+        }
+
+        UpdateButton.IsEnabled = false;
+        try
+        {
+            var progress = new Progress<int>(value =>
+                SetUpdateStatus("Updater.Status.Downloading", value));
+            await Updater.DownloadAndRestartAsync(_availableUpdate, progress);
+            SetUpdateStatus("Updater.Status.Installing");
+            Close();
+        }
+        catch
+        {
+            SetUpdateStatus("Updater.Status.Failed");
+            UpdateButton.IsEnabled = true;
+        }
+    }
+
+    private async Task CheckForUpdatesAsync()
+    {
+        _availableUpdate = null;
+        UpdateButton.IsEnabled = false;
+        SetUpdateStatus("Updater.Status.Checking");
+        try
+        {
+            _availableUpdate = await Updater.CheckAsync(BuildInfo.CommitSha);
+            SetUpdateStatus(
+                _availableUpdate is null ? "Updater.Status.Current" : "Updater.Status.Available",
+                _availableUpdate?.Sha ?? BuildInfo.CommitSha ?? "dev");
+        }
+        catch (OperationCanceledException)
+        {
+            SetUpdateStatus("Updater.Status.Timeout");
+        }
+        catch (PlatformNotSupportedException)
+        {
+            SetUpdateStatus("Updater.Status.Unsupported");
+        }
+        catch
+        {
+            SetUpdateStatus("Updater.Status.Failed");
+        }
+        finally
+        {
+            UpdateButton.IsEnabled = true;
+            RefreshUpdateText();
+        }
+    }
+
+    private void SetUpdateStatus(string key, params object?[] args)
+    {
+        _updateStatusKey = key;
+        _updateStatusArgs = args;
+        RefreshUpdateText();
+    }
+
+    private void RefreshUpdateText()
+    {
+        UpdateStatusText.Text = Localization.Instance.Format(_updateStatusKey, _updateStatusArgs);
+        UpdateButton.Content = Localization.Instance.Get(
+            _availableUpdate is null ? "Updater.Check" : "Updater.DownloadRestart");
+    }
+
     // Environment variables set on this process at the previous launch; children
     // inherit the process environment, so stale names must be cleared explicitly.
     private readonly HashSet<string> _appliedEnvironmentVariables = new(StringComparer.OrdinalIgnoreCase);

src/SharpEmu.GUI/Updater.cs

@@ -0,0 +1,253 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Diagnostics;
+using System.Formats.Tar;
+using System.IO.Compression;
+using System.Net.Http.Headers;
+using System.Runtime.InteropServices;
+using System.Text.Json;
+
+namespace SharpEmu.GUI;
+
+/// <summary>Self-contained Windows updater; the emulator layers do not depend on it.</summary>
+public static class Updater
+{
+    private const string ApplyArgument = "--sharpemu-apply-update";
+    private const string LatestReleaseUrl = "https://api.github.com/repos/sharpemu/sharpemu/releases/latest";
+    private static readonly TimeSpan CheckTimeout = TimeSpan.FromSeconds(10);
+    private static readonly HttpClient Http = CreateHttpClient();
+
+    public sealed record UpdateInfo(string Sha, string Name, string DownloadUrl, long Size);
+
+    public static async Task<UpdateInfo?> CheckAsync(string? currentSha, CancellationToken cancellationToken = default)
+    {
+        var platform = CurrentPlatform();
+        using var timeout = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+        timeout.CancelAfter(CheckTimeout);
+
+        using var response = await Http.GetAsync(LatestReleaseUrl, timeout.Token);
+        response.EnsureSuccessStatusCode();
+        return ParseRelease(
+            await response.Content.ReadAsStringAsync(timeout.Token),
+            currentSha,
+            platform.Rid,
+            platform.Extension);
+    }
+
+    public static async Task DownloadAndRestartAsync(
+        UpdateInfo update,
+        IProgress<int>? progress = null,
+        CancellationToken cancellationToken = default)
+    {
+        var root = Path.Combine(Path.GetTempPath(), "SharpEmu.Update");
+        var payload = Path.Combine(root, "payload");
+        if (Directory.Exists(root))
+        {
+            Directory.Delete(root, recursive: true);
+        }
+
+        Directory.CreateDirectory(root);
+        var archive = Path.Combine(root, update.Name);
+        using (var response = await Http.GetAsync(update.DownloadUrl, HttpCompletionOption.ResponseHeadersRead, cancellationToken))
+        {
+            response.EnsureSuccessStatusCode();
+            await using var input = await response.Content.ReadAsStreamAsync(cancellationToken);
+            await using var output = File.Create(archive);
+            var buffer = new byte[81920];
+            long written = 0;
+            int read;
+            while ((read = await input.ReadAsync(buffer, cancellationToken)) > 0)
+            {
+                await output.WriteAsync(buffer.AsMemory(0, read), cancellationToken);
+                written += read;
+                progress?.Report(update.Size == 0 ? 0 : (int)(written * 100 / update.Size));
+            }
+
+            if (written != update.Size)
+            {
+                throw new InvalidDataException($"Downloaded {written} bytes; expected {update.Size}.");
+            }
+        }
+
+        var platform = CurrentPlatform();
+        var stagedExe = ExtractArchive(archive, payload, platform.Extension, platform.ExecutableName);
+
+        var start = new ProcessStartInfo(stagedExe)
+        {
+            UseShellExecute = false,
+            WorkingDirectory = payload,
+        };
+        start.ArgumentList.Add(ApplyArgument);
+        start.ArgumentList.Add(Environment.ProcessId.ToString());
+        start.ArgumentList.Add(AppContext.BaseDirectory);
+        using var helper = Process.Start(start)
+            ?? throw new InvalidOperationException("The update installer could not be started.");
+    }
+
+    /// <summary>Runs from the downloaded executable after the old GUI exits.</summary>
+    public static bool TryApply(string[] args, out int exitCode)
+    {
+        exitCode = 0;
+        if (args.Length != 3 || args[0] != ApplyArgument)
+        {
+            return false;
+        }
+
+        try
+        {
+            if (int.TryParse(args[1], out var oldPid))
+            {
+                try
+                {
+                    if (!Process.GetProcessById(oldPid).WaitForExit(30_000))
+                    {
+                        throw new TimeoutException("SharpEmu did not close within 30 seconds.");
+                    }
+                }
+                catch (ArgumentException)
+                {
+                    // The old process has already exited.
+                }
+            }
+
+            var source = AppContext.BaseDirectory;
+            var target = Path.GetFullPath(args[2]);
+            foreach (var file in Directory.EnumerateFiles(source, "*", SearchOption.AllDirectories))
+            {
+                var relative = Path.GetRelativePath(source, file);
+                if (relative.Equals("gui-settings.json", StringComparison.OrdinalIgnoreCase) ||
+                    relative.StartsWith("user" + Path.DirectorySeparatorChar, StringComparison.OrdinalIgnoreCase) ||
+                    relative.StartsWith("logs" + Path.DirectorySeparatorChar, StringComparison.OrdinalIgnoreCase) ||
+                    relative.StartsWith("Languages" + Path.DirectorySeparatorChar, StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                var destination = Path.Combine(target, relative);
+                Directory.CreateDirectory(Path.GetDirectoryName(destination)!);
+                File.Copy(file, destination, overwrite: true);
+                if (!OperatingSystem.IsWindows())
+                {
+                    File.SetUnixFileMode(destination, File.GetUnixFileMode(file));
+                }
+            }
+
+            using var restarted = Process.Start(new ProcessStartInfo(
+                Path.Combine(target, CurrentPlatform().ExecutableName))
+            {
+                UseShellExecute = false,
+                WorkingDirectory = target,
+            }) ?? throw new InvalidOperationException("The updated SharpEmu could not be started.");
+        }
+        catch (Exception ex)
+        {
+            exitCode = 1;
+            try
+            {
+                File.WriteAllText(Path.Combine(args[2], "update-error.log"), ex.ToString());
+            }
+            catch
+            {
+                // Best-effort diagnostics only.
+            }
+        }
+
+        return true;
+    }
+
+    private static UpdateInfo? ParseRelease(
+        string json,
+        string? currentSha,
+        string rid,
+        string extension)
+    {
+        using var document = JsonDocument.Parse(json);
+        var candidates = new List<(DateTimeOffset Created, UpdateInfo Update)>();
+        foreach (var asset in document.RootElement.GetProperty("assets").EnumerateArray())
+        {
+            var name = asset.GetProperty("name").GetString() ?? "";
+            var marker = $"-{rid}-";
+            var markerIndex = name.LastIndexOf(marker, StringComparison.OrdinalIgnoreCase);
+            if (!name.EndsWith(extension, StringComparison.OrdinalIgnoreCase) ||
+                markerIndex < 0)
+            {
+                continue;
+            }
+
+            var sha = name[(markerIndex + marker.Length)..^extension.Length];
+            if (sha.Length < 7 || !sha.All(Uri.IsHexDigit))
+            {
+                continue;
+            }
+
+            candidates.Add((
+                asset.GetProperty("created_at").GetDateTimeOffset(),
+                new UpdateInfo(
+                    sha,
+                    name,
+                    asset.GetProperty("browser_download_url").GetString()!,
+                    asset.GetProperty("size").GetInt64())));
+        }
+
+        var latest = candidates.OrderByDescending(candidate => candidate.Created).FirstOrDefault().Update;
+        return latest is null || string.Equals(latest.Sha, currentSha, StringComparison.OrdinalIgnoreCase)
+            ? null
+            : latest;
+    }
+
+    private static string ExtractArchive(
+        string archive,
+        string payload,
+        string extension,
+        string executableName)
+    {
+        if (extension == ".zip")
+        {
+            ZipFile.ExtractToDirectory(archive, payload);
+        }
+        else
+        {
+            Directory.CreateDirectory(payload);
+            using var compressed = File.OpenRead(archive);
+            using var gzip = new GZipStream(compressed, CompressionMode.Decompress);
+            TarFile.ExtractToDirectory(gzip, payload, overwriteFiles: false);
+        }
+
+        var executable = Path.Combine(payload, executableName);
+        if (!File.Exists(executable))
+        {
+            throw new InvalidDataException($"The update archive does not contain {executableName}.");
+        }
+
+        if (!OperatingSystem.IsWindows())
+        {
+            File.SetUnixFileMode(executable, File.GetUnixFileMode(executable) | UnixFileMode.UserExecute);
+        }
+
+        return executable;
+    }
+
+    private static HttpClient CreateHttpClient()
+    {
+        var client = new HttpClient { Timeout = Timeout.InfiniteTimeSpan };
+        client.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("SharpEmu", "0.0.1"));
+        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/vnd.github+json"));
+        return client;
+    }
+
+    private static PlatformInfo CurrentPlatform()
+    {
+        if (RuntimeInformation.ProcessArchitecture != Architecture.X64)
+        {
+            throw new PlatformNotSupportedException("SharpEmu releases require an x64 process.");
+        }
+
+        if (OperatingSystem.IsWindows()) return new("win-x64", ".zip", "SharpEmu.exe");
+        if (OperatingSystem.IsLinux()) return new("linux-x64", ".tar.gz", "SharpEmu");
+        if (OperatingSystem.IsMacOS()) return new("osx-x64", ".tar.gz", "SharpEmu");
+        throw new PlatformNotSupportedException();
+    }
+
+    private sealed record PlatformInfo(string Rid, string Extension, string ExecutableName);
+}

src/SharpEmu.HLE/Host/Posix/PosixHostMemory.cs

@@ -163,13 +163,18 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
         private const int PROT_EXEC = 0x4;
 
         private const int MAP_PRIVATE = 0x02;
-        private const int MAP_FIXED = 0x10;
         private static readonly int MAP_ANON = OperatingSystem.IsMacOS() ? 0x1000 : 0x20;
         private static readonly int MAP_NORESERVE = OperatingSystem.IsMacOS() ? 0 : 0x4000;
 
         // Linux-only: fail instead of clobbering an existing mapping.
         private const int MAP_FIXED_NOREPLACE = 0x100000;
 
+        private const int KERN_SUCCESS = 0;
+
+        // On Darwin fixed placement is represented by the absence of
+        // VM_FLAGS_ANYWHERE. Do not add VM_FLAGS_OVERWRITE: overlap must fail.
+        private const int VM_FLAGS_FIXED = 0;
+
         private static readonly nint MAP_FAILED = -1;
 
         private static readonly object Gate = new();
@@ -181,6 +186,7 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
             public ulong Size;
             public uint DefaultProtect;
             public Dictionary<ulong, uint>? PageProtects;
+            public bool UsesMachAllocation;
 
             public ulong End => Base + Size;
 
@@ -251,6 +257,7 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
                 }
 
                 nint result;
+                var usesMachAllocation = false;
                 if (address != null)
                 {
                     // Win32 maps at exactly the requested address or fails
@@ -280,15 +287,17 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
                     if (result == MAP_FAILED && OperatingSystem.IsMacOS())
                     {
                         // The hint-only attempt above didn't land at the requested
-                        // address. This is routinely the case for the PS5's fixed
-                        // 32 GiB image base under Rosetta 2 on Apple Silicon, where
-                        // the kernel never honors that hint. Retry with true
-                        // MAP_FIXED: this can clobber an untracked host mapping
-                        // (dyld, the runtime's JIT heap, Rosetta) if one already
-                        // sits exactly there, but without it guest images that
-                        // require this base never load at all on macOS.
-                        Trace($"exact mmap hint failed, retrying with MAP_FIXED: addr=0x{(ulong)address:X16}");
-                        result = mmap((nint)address, (nuint)alignedSize, posixProtect, flags | MAP_FIXED, -1, 0);
+                        // address. mach_vm_allocate with fixed placement and no
+                        // overwrite flag atomically maps the requested range or
+                        // fails if any host mapping already owns it. Unlike
+                        // MAP_FIXED, it cannot clobber CLR, dyld, JIT, or Rosetta
+                        // memory that is absent from our shadow table.
+                        Trace($"exact mmap hint failed, retrying with fixed Mach allocation: addr=0x{(ulong)address:X16}");
+                        result = AllocateDarwinFixed(
+                            (nint)address,
+                            alignedSize,
+                            posixProtect);
+                        usesMachAllocation = result != MAP_FAILED;
                     }
 
                     if (result == MAP_FAILED || (ulong)result != (ulong)address)
@@ -316,7 +325,8 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
                 {
                     Base = (ulong)result,
                     Size = alignedSize,
-                    DefaultProtect = protect
+                    DefaultProtect = protect,
+                    UsesMachAllocation = usesMachAllocation,
                 };
 
                 return (void*)result;
@@ -335,8 +345,15 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
                     return false;
                 }
 
-                Regions.Remove((ulong)address);
-                return munmap((nint)address, (nuint)region.Size) == 0;
+                var released = region.UsesMachAllocation
+                    ? mach_vm_deallocate(mach_task_self(), (ulong)address, region.Size) == KERN_SUCCESS
+                    : munmap((nint)address, (nuint)region.Size) == 0;
+                if (released)
+                {
+                    Regions.Remove((ulong)address);
+                }
+
+                return released;
             }
         }
 
@@ -504,6 +521,40 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
             };
         }
 
+        private static nint AllocateDarwinFixed(nint requestedAddress, ulong size, int posixProtect)
+        {
+            var address = (ulong)requestedAddress;
+            var result = mach_vm_allocate(
+                mach_task_self(),
+                ref address,
+                size,
+                VM_FLAGS_FIXED);
+            if (result != KERN_SUCCESS || address != (ulong)requestedAddress)
+            {
+                if (result == KERN_SUCCESS)
+                {
+                    _ = mach_vm_deallocate(mach_task_self(), address, size);
+                }
+
+                Trace(
+                    $"fixed Mach allocation failed: addr=0x{(ulong)requestedAddress:X16} " +
+                    $"size=0x{size:X} kern_return={result}");
+                return MAP_FAILED;
+            }
+
+            if (mprotect((nint)address, (nuint)size, posixProtect) == 0)
+            {
+                return (nint)address;
+            }
+
+            var error = Marshal.GetLastPInvokeError();
+            _ = mach_vm_deallocate(mach_task_self(), address, size);
+            Trace(
+                $"fixed Mach allocation protection failed: addr=0x{address:X16} " +
+                $"size=0x{size:X} errno={error}");
+            return MAP_FAILED;
+        }
+
         private static void Trace(string message)
         {
             if (string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_VMEM"), "1", StringComparison.Ordinal))
@@ -524,5 +575,14 @@ internal sealed unsafe class PosixHostMemory : IHostMemory
 
         [DllImport("libc", SetLastError = true)]
         private static extern int mprotect(nint addr, nuint length, int prot);
+
+        [DllImport("libSystem.B.dylib")]
+        private static extern uint mach_task_self();
+
+        [DllImport("libSystem.B.dylib")]
+        private static extern int mach_vm_allocate(uint target, ref ulong address, ulong size, int flags);
+
+        [DllImport("libSystem.B.dylib")]
+        private static extern int mach_vm_deallocate(uint target, ulong address, ulong size);
     }
 }

src/SharpEmu.HLE/SharpEmu.HLE.csproj

@@ -14,6 +14,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
 
   <ItemGroup>
     <InternalsVisibleTo Include="SharpEmu.Core" />
+    <InternalsVisibleTo Include="SharpEmu.Libs.Tests" />
   </ItemGroup>
 
   <ItemGroup>

src/SharpEmu.Libs/Agc/AgcExports.cs

@@ -5937,16 +5937,30 @@ public static partial class AgcExports
         // draw a multi-render-target G-buffer (up to eight slots) in one pass.
         // Fall back to slot 0 if we cannot match any export to a bound target.
         var allBoundTargets = GetRenderTargets(state.CxRegisters);
-        var renderTargets = allBoundTargets
-            .Where(target => HasPixelColorExport(pixelState, target.Slot))
-            .OrderBy(target => target.Slot)
-            .ToArray();
-        if (renderTargets.Length == 0)
+        // At most 8 slots; a manual filter avoids the per-draw LINQ iterator/
+        // closure allocations. Slots are distinct, so sorting by slot is stable.
+        var selectedTargets = new List<RenderTargetDescriptor>(allBoundTargets.Count);
+        foreach (var target in allBoundTargets)
         {
-            renderTargets = allBoundTargets
-                .Where(target => target.Slot == 0)
-                .ToArray();
+            if (HasPixelColorExport(pixelState, target.Slot))
+            {
+                selectedTargets.Add(target);
+            }
         }
+
+        if (selectedTargets.Count == 0)
+        {
+            foreach (var target in allBoundTargets)
+            {
+                if (target.Slot == 0)
+                {
+                    selectedTargets.Add(target);
+                }
+            }
+        }
+
+        selectedTargets.Sort(static (left, right) => left.Slot.CompareTo(right.Slot));
+        var renderTargets = selectedTargets.ToArray();
         if (_traceAgcShader && allBoundTargets.Count > 1)
         {
             TraceAgcShader(
@@ -6398,12 +6412,23 @@ public static partial class AgcExports
     private static bool HasPixelColorExport(Gen5ShaderState state, uint target) =>
         GetPixelColorExportMask(state, target) != 0;
 
-    private static uint GetPixelColorExportMask(Gen5ShaderState state, uint target) =>
-        state.Program.Instructions
-            .Select(instruction => instruction.Control)
-            .OfType<Gen5ExportControl>()
-            .Where(export => export.Target == target)
-            .Aggregate(0u, (mask, export) => mask | (export.EnableMask & 0xFu));
+    private static uint GetPixelColorExportMask(Gen5ShaderState state, uint target)
+    {
+        // Called per render target (twice per draw via CreateRenderState +
+        // HasPixelColorExport); a manual scan avoids the per-call LINQ iterator
+        // and closure allocations. Same result as the previous
+        // Select/OfType/Where/Aggregate chain.
+        var mask = 0u;
+        foreach (var instruction in state.Program.Instructions)
+        {
+            if (instruction.Control is Gen5ExportControl export && export.Target == target)
+            {
+                mask |= export.EnableMask & 0xFu;
+            }
+        }
+
+        return mask;
+    }
 
     private static uint GetInterpolatedAttributeCount(Gen5ShaderState state)
     {

src/SharpEmu.Libs/Kernel/KernelEventFlagCompatExports.cs

@@ -25,6 +25,11 @@ public static class KernelEventFlagCompatExports
     private static readonly ConcurrentDictionary<ulong, EventFlagState> _eventFlags = new();
     private static long _nextEventFlagHandle = 1;
 
+    // Cached once: gating every call site avoids building the interpolated
+    // trace string (and FormatFrameChain/FormatGuestWaitObject) when disabled.
+    private static readonly bool _traceEventFlag = string.Equals(
+        Environment.GetEnvironmentVariable("SHARPEMU_LOG_EVENT_FLAG"), "1", StringComparison.Ordinal);
+
     private sealed class EventFlagState
     {
         public required string Name { get; init; }
@@ -79,7 +84,7 @@ public static class KernelEventFlagCompatExports
             return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT);
         }
 
-        TraceEventFlag($"create handle=0x{handle:X16} name='{name}' attr=0x{attributes:X2} bits=0x{initialPattern:X16}");
+        if (_traceEventFlag) TraceEventFlag($"create handle=0x{handle:X16} name='{name}' attr=0x{attributes:X2} bits=0x{initialPattern:X16}");
         return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_OK);
     }
 
@@ -101,7 +106,7 @@ public static class KernelEventFlagCompatExports
             Monitor.PulseAll(state.Gate);
         }
 
-        TraceEventFlag($"delete handle=0x{handle:X16} name='{state.Name}'");
+        if (_traceEventFlag) TraceEventFlag($"delete handle=0x{handle:X16} name='{state.Name}'");
         return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_OK);
     }
 
@@ -124,7 +129,7 @@ public static class KernelEventFlagCompatExports
         {
             state.Bits |= pattern;
             Monitor.PulseAll(state.Gate);
-            TraceEventFlag($"set handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} ret=0x{returnRip:X16}");
+            if (_traceEventFlag) TraceEventFlag($"set handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} ret=0x{returnRip:X16}");
         }
 
         _ = GuestThreadExecution.Scheduler?.WakeBlockedThreads(GetEventFlagWakeKey(handle));
@@ -148,7 +153,7 @@ public static class KernelEventFlagCompatExports
         lock (state.Gate)
         {
             state.Bits &= pattern;
-            TraceEventFlag($"clear handle=0x{handle:X16} mask=0x{pattern:X16} bits=0x{state.Bits:X16}");
+            if (_traceEventFlag) TraceEventFlag($"clear handle=0x{handle:X16} mask=0x{pattern:X16} bits=0x{state.Bits:X16}");
         }
 
         return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_OK);
@@ -189,7 +194,7 @@ public static class KernelEventFlagCompatExports
             }
 
             ApplyClearMode(state, pattern, waitMode);
-            TraceEventFlag($"poll handle=0x{handle:X16} pattern=0x{pattern:X16} mode=0x{waitMode:X2} bits=0x{state.Bits:X16}");
+            if (_traceEventFlag) TraceEventFlag($"poll handle=0x{handle:X16} pattern=0x{pattern:X16} mode=0x{waitMode:X2} bits=0x{state.Bits:X16}");
             return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_OK);
         }
     }
@@ -287,8 +292,8 @@ public static class KernelEventFlagCompatExports
                     return true;
                 },
                 deadline);
-            TraceEventFlag($"wait-unsatisfied handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} guest_thread=0x{currentGuestThread:X16} fiber=0x{currentFiber:X16} managed={managedThread} block={requestedBlock} ret=0x{returnRip:X16} frames={FormatFrameChain(ctx)}");
-            TraceEventFlag($"wait-object handle=0x{handle:X16} name='{state.Name}' {FormatGuestWaitObject(ctx)}");
+            if (_traceEventFlag) TraceEventFlag($"wait-unsatisfied handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} guest_thread=0x{currentGuestThread:X16} fiber=0x{currentFiber:X16} managed={managedThread} block={requestedBlock} ret=0x{returnRip:X16} frames={FormatFrameChain(ctx)}");
+            if (_traceEventFlag) TraceEventFlag($"wait-object handle=0x{handle:X16} name='{state.Name}' {FormatGuestWaitObject(ctx)}");
             if (!requestedBlock)
             {
                 var scheduler = GuestThreadExecution.Scheduler;
@@ -298,7 +303,7 @@ public static class KernelEventFlagCompatExports
                 }
 
                 state.WaitingThreads++;
-                TraceEventFlag($"wait-pump handle=0x{handle:X16} pattern=0x{pattern:X16} waiters={state.WaitingThreads} guest_thread=0x{currentGuestThread:X16} fiber=0x{currentFiber:X16} managed={managedThread} ret=0x{returnRip:X16}");
+                if (_traceEventFlag) TraceEventFlag($"wait-pump handle=0x{handle:X16} pattern=0x{pattern:X16} waiters={state.WaitingThreads} guest_thread=0x{currentGuestThread:X16} fiber=0x{currentFiber:X16} managed={managedThread} ret=0x{returnRip:X16}");
                 var releaseWaiter = true;
                 try
                 {
@@ -318,7 +323,7 @@ public static class KernelEventFlagCompatExports
                         {
                             state.WaitingThreads = Math.Max(0, state.WaitingThreads - 1);
                             releaseWaiter = false;
-                            TraceEventFlag($"wait-wake handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} waiters={state.WaitingThreads} ret=0x{returnRip:X16}");
+                            if (_traceEventFlag) TraceEventFlag($"wait-wake handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} waiters={state.WaitingThreads} ret=0x{returnRip:X16}");
                             return SetReturn(ctx, pumpedWaitResult);
                         }
 
@@ -329,7 +334,7 @@ public static class KernelEventFlagCompatExports
                             releaseWaiter = false;
                             _ = TryWriteUInt32(ctx, timeoutAddress, 0);
                             _ = TryWriteResultPattern(ctx, resultAddress, state.Bits);
-                            TraceEventFlag($"wait-timeout handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} ret=0x{returnRip:X16}");
+                            if (_traceEventFlag) TraceEventFlag($"wait-timeout handle=0x{handle:X16} pattern=0x{pattern:X16} bits=0x{state.Bits:X16} ret=0x{returnRip:X16}");
                             return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_ERROR_TIMED_OUT);
                         }
 
@@ -346,7 +351,7 @@ public static class KernelEventFlagCompatExports
             }
 
             state.WaitingThreads++;
-            TraceEventFlag($"wait-block handle=0x{handle:X16} pattern=0x{pattern:X16} waiters={state.WaitingThreads} guest_thread=0x{currentGuestThread:X16} fiber=0x{currentFiber:X16} managed={managedThread} ret=0x{returnRip:X16}");
+            if (_traceEventFlag) TraceEventFlag($"wait-block handle=0x{handle:X16} pattern=0x{pattern:X16} waiters={state.WaitingThreads} guest_thread=0x{currentGuestThread:X16} fiber=0x{currentFiber:X16} managed={managedThread} ret=0x{returnRip:X16}");
             return SetReturn(ctx, OrbisGen2Result.ORBIS_GEN2_OK);
         }
         finally
@@ -381,7 +386,7 @@ public static class KernelEventFlagCompatExports
             state.Bits = setPattern;
             state.WaitingThreads = 0;
             Monitor.PulseAll(state.Gate);
-            TraceEventFlag(
+            if (_traceEventFlag) TraceEventFlag(
                 $"cancel handle=0x{handle:X16} bits=0x{setPattern:X16} " +
                 $"guest_thread=0x{GuestThreadExecution.CurrentGuestThreadHandle:X16} ret=0x{GetCurrentReturnRip():X16}");
         }
@@ -476,7 +481,7 @@ public static class KernelEventFlagCompatExports
             }
 
             state.WaitingThreads = Math.Max(0, state.WaitingThreads - 1);
-            TraceEventFlag(
+            if (_traceEventFlag) TraceEventFlag(
                 $"wait-wake pattern=0x{pattern:X16} mode=0x{waitMode:X2} bits=0x{state.Bits:X16} waiters={state.WaitingThreads}");
             return true;
         }
@@ -568,7 +573,7 @@ public static class KernelEventFlagCompatExports
 
     private static void TraceEventFlag(string message)
     {
-        if (string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_EVENT_FLAG"), "1", StringComparison.Ordinal))
+        if (_traceEventFlag)
         {
             Console.Error.WriteLine($"[LOADER][TRACE] event_flag.{message}");
         }

src/SharpEmu.Libs/Kernel/KernelMemoryCompatExports.cs

@@ -102,7 +102,11 @@ public static partial class KernelMemoryCompatExports
     private static readonly object _guestMountGate = new();
     private static readonly Dictionary<ulong, DirectAllocation> _directAllocations = new();
     private static readonly Dictionary<ulong, LibcHeapAllocation> _libcAllocations = new();
-    private static readonly Dictionary<ulong, MappedRegion> _mappedRegions = new();
+    // Keyed by (and kept sorted on) region base address so VirtualQuery can find a
+    // containing/next region with a binary search instead of an O(n) scan. Every
+    // write uses the region's own Address as the key (see AddMappedRegionSliceLocked
+    // and the mmap sites), so Values enumerate in ascending address order.
+    private static readonly SortedList<ulong, MappedRegion> _mappedRegions = new();
     private static readonly Dictionary<ulong, string> _mappedRegionNames = new();
     private static readonly Dictionary<string, string> _guestMounts = new(StringComparer.OrdinalIgnoreCase);
     private static readonly HashSet<string> _tracedStatResults = new(StringComparer.Ordinal);
@@ -1574,7 +1578,27 @@ public static partial class KernelMemoryCompatExports
         ExportName = "stat",
         Target = Generation.Gen4 | Generation.Gen5,
         LibraryName = "libc")]
-    public static int PosixStat(CpuContext ctx) => KernelStat(ctx);
+    public static int PosixStat(CpuContext ctx)
+    {
+        var result = KernelStat(ctx);
+        if (result == (int)OrbisGen2Result.ORBIS_GEN2_OK)
+        {
+            return 0;
+        }
+
+        // stat(2) follows the libc/POSIX ABI: failures return -1 and expose
+        // the reason through errno. Returning the raw Orbis kernel code here
+        // makes callers treat a missing file as a non-negative success value.
+        var errno = result switch
+        {
+            (int)OrbisGen2Result.ORBIS_GEN2_ERROR_INVALID_ARGUMENT => Einval,
+            (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT => Efault,
+            _ => 2, // ENOENT
+        };
+        KernelRuntimeCompatExports.TrySetErrno(ctx, errno);
+        ctx[CpuRegister.Rax] = ulong.MaxValue;
+        return -1;
+    }
 
     [SysAbiExport(
         Nid = "gEpBkcwxUjw",
@@ -4013,7 +4037,7 @@ public static partial class KernelMemoryCompatExports
                             _ => unchecked((int)argumentSource.NextGpArg())
                         };
 
-                        var formatted = value.ToString();
+                        var formatted = value.ToString(CultureInfo.InvariantCulture);
                         if (showSign && value >= 0)
                             formatted = "+" + formatted;
                         else if (spaceForSign && value >= 0)
@@ -4033,7 +4057,7 @@ public static partial class KernelMemoryCompatExports
                             _ => (uint)argumentSource.NextGpArg()
                         };
 
-                        var formatted = value.ToString();
+                        var formatted = value.ToString(CultureInfo.InvariantCulture);
                         sb.Append(PadString(formatted, width, leftAlign, padWithZero && !leftAlign));
                     }
                     break;
@@ -4050,8 +4074,8 @@ public static partial class KernelMemoryCompatExports
                         };
 
                         var formatted = specifier == 'x'
-                            ? value.ToString("x")
-                            : value.ToString("X");
+                            ? value.ToString("x", CultureInfo.InvariantCulture)
+                            : value.ToString("X", CultureInfo.InvariantCulture);
 
                         if (alternateForm && value != 0)
                             formatted = specifier == 'x' ? "0x" + formatted : "0X" + formatted;
@@ -4155,7 +4179,10 @@ public static partial class KernelMemoryCompatExports
                         var formatStr = precision >= 0
                             ? $"{{0:{specifier}{precision}}}"
                             : $"{{0:{specifier}}}";
-                        var formatted = string.Format(formatStr, value);
+                        var formatted = string.Format(
+                            CultureInfo.InvariantCulture,
+                            formatStr,
+                            value);
 
                         if (showSign && value >= 0)
                             formatted = "+" + formatted;
@@ -4219,31 +4246,50 @@ public static partial class KernelMemoryCompatExports
     {
         private readonly CpuContext _ctx;
         private int _gpIndex;
+        private int _fpIndex;
+        private int _stackIndex;
 
         public RegisterPrintfArgumentSource(CpuContext ctx, int gpIndex)
         {
             _ctx = ctx;
             _gpIndex = gpIndex;
+            _fpIndex = 0;
+            _stackIndex = 0;
         }
 
         public ulong NextGpArg()
         {
-            var index = _gpIndex++;
-            return index switch
+            var index = _gpIndex;
+            if (index < 6)
             {
-                0 => _ctx[CpuRegister.Rdi],
-                1 => _ctx[CpuRegister.Rsi],
-                2 => _ctx[CpuRegister.Rdx],
-                3 => _ctx[CpuRegister.Rcx],
-                4 => _ctx[CpuRegister.R8],
-                5 => _ctx[CpuRegister.R9],
-                _ => ReadStackArg(_ctx, (ulong)(index - 6) * 8)
-            };
+                _gpIndex++;
+                return index switch
+                {
+                    0 => _ctx[CpuRegister.Rdi],
+                    1 => _ctx[CpuRegister.Rsi],
+                    2 => _ctx[CpuRegister.Rdx],
+                    3 => _ctx[CpuRegister.Rcx],
+                    4 => _ctx[CpuRegister.R8],
+                    _ => _ctx[CpuRegister.R9],
+                };
+            }
+
+            return ReadStackArg(_ctx, (ulong)(_stackIndex++) * 8);
         }
 
         public double NextFloatArg()
         {
-            return BitConverter.Int64BitsToDouble(unchecked((long)NextGpArg()));
+            ulong bits;
+            if (_fpIndex < 8)
+            {
+                _ctx.GetXmmRegister(_fpIndex++, out bits, out _);
+            }
+            else
+            {
+                bits = ReadStackArg(_ctx, (ulong)(_stackIndex++) * 8);
+            }
+
+            return BitConverter.Int64BitsToDouble(unchecked((long)bits));
         }
     }
 
@@ -4806,8 +4852,19 @@ public static partial class KernelMemoryCompatExports
     private static bool IsMutatingOpen(int flags) =>
         (flags & (O_WRONLY | O_RDWR | O_CREAT | O_TRUNC | O_APPEND)) != 0;
 
+    // Dev-build dumps (unpackaged UE titles, etc.) may write their Saved/ tree under
+    // /app0, which is read-only on retail hardware. Opt in via SHARPEMU_WRITABLE_APP0=1
+    // to allow those writes so such dumps can boot; defaults off to keep retail semantics.
+    private static readonly bool _writableApp0 =
+        string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_WRITABLE_APP0"), "1", StringComparison.Ordinal);
+
     public static bool IsReadOnlyGuestMutationPath(string guestPath)
     {
+        if (_writableApp0)
+        {
+            return false;
+        }
+
         var normalized = NormalizeGuestStatCachePath(guestPath);
         return normalized is not null &&
                (string.Equals(normalized, "/app0", StringComparison.OrdinalIgnoreCase) ||
@@ -5427,7 +5484,9 @@ public static partial class KernelMemoryCompatExports
 
         var affected = new List<MappedRegion>();
         var cursor = address;
-        foreach (var region in _mappedRegions.Values.OrderBy(static region => region.Address))
+        // _mappedRegions is a SortedList keyed by address, so Values already
+        // enumerate in ascending address order.
+        foreach (var region in _mappedRegions.Values)
         {
             if (!TryAddU64(region.Address, region.Length, out var regionEnd) || regionEnd <= cursor)
             {
@@ -5588,9 +5647,33 @@ public static partial class KernelMemoryCompatExports
     private static bool TryFindVirtualQueryRegionLocked(ulong queryAddress, bool findNext, out MappedRegion region)
     {
         region = default;
-        var foundNext = false;
-        foreach (var candidate in _mappedRegions.Values)
+        var keys = _mappedRegions.Keys;
+        var values = _mappedRegions.Values;
+        var count = keys.Count;
+
+        // First index whose region address is >= queryAddress.
+        var lo = 0;
+        var hi = count;
+        while (lo < hi)
         {
+            var mid = (int)(((uint)lo + (uint)hi) >> 1);
+            if (keys[mid] < queryAddress)
+            {
+                lo = mid + 1;
+            }
+            else
+            {
+                hi = mid;
+            }
+        }
+
+        // Regions do not overlap, so only the one with the greatest base address
+        // <= queryAddress can contain it — index lo when it starts exactly at
+        // queryAddress, otherwise lo - 1.
+        var floorIndex = (lo < count && keys[lo] == queryAddress) ? lo : lo - 1;
+        if (floorIndex >= 0)
+        {
+            var candidate = values[floorIndex];
             if (TryAddU64(candidate.Address, candidate.Length, out var candidateEnd) &&
                 queryAddress >= candidate.Address &&
                 queryAddress < candidateEnd)
@@ -5598,20 +5681,16 @@ public static partial class KernelMemoryCompatExports
                 region = candidate;
                 return true;
             }
-
-            if (!findNext || candidate.Address < queryAddress)
-            {
-                continue;
-            }
-
-            if (!foundNext || candidate.Address < region.Address)
-            {
-                region = candidate;
-                foundNext = true;
-            }
         }
 
-        return foundNext;
+        // findNext: the region with the smallest base address >= queryAddress.
+        if (findNext && lo < count)
+        {
+            region = values[lo];
+            return true;
+        }
+
+        return false;
     }
 
     private static void TraceDirectMemoryCall(
@@ -5640,10 +5719,12 @@ public static partial class KernelMemoryCompatExports
             $"[LOADER][TRACE] {operation}: ret=0x{returnRip:X16} len=0x{length:X16} align=0x{alignment:X16} type=0x{memoryType:X8} out=0x{outAddress:X16} selected=0x{selectedAddress:X16} result={result?.ToString() ?? "<pending>"}");
     }
 
-    private static bool ShouldTraceDirectMemory()
-    {
-        return string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_DIRECT_MEMORY"), "1", StringComparison.Ordinal);
-    }
+    // Cached once so the ~8 direct-memory call sites don't each do a
+    // GetEnvironmentVariable P/Invoke per operation.
+    private static readonly bool _traceDirectMemory = string.Equals(
+        Environment.GetEnvironmentVariable("SHARPEMU_LOG_DIRECT_MEMORY"), "1", StringComparison.Ordinal);
+
+    private static bool ShouldTraceDirectMemory() => _traceDirectMemory;
 
     private static bool TryReleaseDirectMemoryRangeLocked(ulong start, ulong length)
     {

src/SharpEmu.Libs/Network/NetExports.cs

@@ -344,8 +344,10 @@ public static class NetExports
     public static int NetHtonl(CpuContext ctx)
     {
         var value = unchecked((uint)ctx[CpuRegister.Rdi]);
+        // The byte-swapped result is the return value and already lives in Rax; return OK as the
+        // dispatch status without going through SetReturn, which would overwrite Rax with 0.
         ctx[CpuRegister.Rax] = BinaryPrimitives.ReverseEndianness(value);
-        return ctx.SetReturn(0);
+        return (int)OrbisGen2Result.ORBIS_GEN2_OK;
     }
 
     [SysAbiExport(
@@ -356,8 +358,10 @@ public static class NetExports
     public static int NetHtons(CpuContext ctx)
     {
         var value = unchecked((ushort)ctx[CpuRegister.Rdi]);
+        // The byte-swapped result is the return value and already lives in Rax; return OK as the
+        // dispatch status without going through SetReturn, which would overwrite Rax with 0.
         ctx[CpuRegister.Rax] = BinaryPrimitives.ReverseEndianness(value);
-        return ctx.SetReturn(0);
+        return (int)OrbisGen2Result.ORBIS_GEN2_OK;
     }
 
     [SysAbiExport(
@@ -368,8 +372,10 @@ public static class NetExports
     public static int NetNtohl(CpuContext ctx)
     {
         var value = unchecked((uint)ctx[CpuRegister.Rdi]);
+        // The byte-swapped result is the return value and already lives in Rax; return OK as the
+        // dispatch status without going through SetReturn, which would overwrite Rax with 0.
         ctx[CpuRegister.Rax] = BinaryPrimitives.ReverseEndianness(value);
-        return ctx.SetReturn(0);
+        return (int)OrbisGen2Result.ORBIS_GEN2_OK;
     }
 
     [SysAbiExport(
@@ -380,8 +386,10 @@ public static class NetExports
     public static int NetNtohs(CpuContext ctx)
     {
         var value = unchecked((ushort)ctx[CpuRegister.Rdi]);
+        // The byte-swapped result is the return value and already lives in Rax; return OK as the
+        // dispatch status without going through SetReturn, which would overwrite Rax with 0.
         ctx[CpuRegister.Rax] = BinaryPrimitives.ReverseEndianness(value);
-        return ctx.SetReturn(0);
+        return (int)OrbisGen2Result.ORBIS_GEN2_OK;
     }
 
     [SysAbiExport(

src/SharpEmu.Libs/Np/NpWebApi2Exports.cs

@@ -43,6 +43,19 @@ public static class NpWebApi2Exports
         return ctx.SetReturn(0);
     }
 
+    [SysAbiExport(
+        Nid = "sk54bi6FtYM",
+        ExportName = "sceNpWebApi2CreateUserContext",
+        Target = Generation.Gen4 | Generation.Gen5,
+        LibraryName = "libSceNpWebApi2")]
+    public static int NpWebApi2CreateUserContext(CpuContext ctx)
+    {
+        // No PSN backend: refuse user-context creation so the title's online
+        // layer backs off instead of driving a half-created context handle.
+        TraceNpWebApi2("create-user-context", unchecked((int)ctx[CpuRegister.Rdi]), ctx[CpuRegister.Rsi]);
+        return ctx.SetReturn(NpWebApi2ErrorInvalidArgument);
+    }
+
     [SysAbiExport(
         Nid = "bEvXpcEk200",
         ExportName = "sceNpWebApi2Terminate",

src/SharpEmu.Libs/Pad/BluetoothHidExports.cs

@@ -1,6 +1,8 @@
 // Copyright (C) 2026 SharpEmu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+using System.Runtime.InteropServices;
+using System.Threading;
 using SharpEmu.HLE;
 
 namespace SharpEmu.Libs.Pad;
@@ -16,6 +18,19 @@ public static class BluetoothHidExports
         "1",
         StringComparison.Ordinal);
 
+    // EXPERIMENT: fire the registered callback once with a zeroed event struct.
+    // Direct execution shares the host address space with the guest, so an
+    // AllocHGlobal buffer is directly readable by guest code.
+    // SHARPEMU_BTHID_FIRE_CALLBACK=1 enables; SHARPEMU_BTHID_EVENT_CODE and
+    // SHARPEMU_BTHID_EVENT_SIZE (default 0 / 256) shape the synthetic event.
+    private static readonly bool _fireCallback = string.Equals(
+        Environment.GetEnvironmentVariable("SHARPEMU_BTHID_FIRE_CALLBACK"),
+        "1",
+        StringComparison.Ordinal);
+
+    private static ulong _callbackFunction;
+    private static int _fired;
+
     private static int Result(CpuContext ctx) =>
         ctx.SetReturn(_reportUnavailable ? BluetoothHidUnavailable : 0);
 
@@ -31,12 +46,101 @@ public static class BluetoothHidExports
         ExportName = "sceBluetoothHidRegisterDevice",
         Target = Generation.Gen4 | Generation.Gen5,
         LibraryName = "libSceBluetoothHid")]
-    public static int BluetoothHidRegisterDevice(CpuContext ctx) => Result(ctx);
+    public static int BluetoothHidRegisterDevice(CpuContext ctx)
+    {
+        var result = Result(ctx);
+        if (_fireCallback && _callbackFunction >= 0x10000 &&
+            Interlocked.Exchange(ref _fired, 1) == 0)
+        {
+            FireEnumerationComplete(ctx);
+        }
+
+        return result;
+    }
 
     [SysAbiExport(
         Nid = "4Ypfo9RIwfM",
         ExportName = "sceBluetoothHidRegisterCallback",
         Target = Generation.Gen4 | Generation.Gen5,
         LibraryName = "libSceBluetoothHid")]
-    public static int BluetoothHidRegisterCallback(CpuContext ctx) => Result(ctx);
+    public static int BluetoothHidRegisterCallback(CpuContext ctx)
+    {
+        _callbackFunction = ctx[CpuRegister.Rdi];
+
+        // EXPERIMENT: failing ONLY the callback registration (with a generic kernel
+        // error, unlike the BT-specific unavailable code) may make wheel/FFB
+        // middleware disable its Bluetooth search loop instead of polling forever.
+        // SHARPEMU_BTHID_CB_FAIL=nf -> NOT_FOUND, =ni -> NOT_IMPLEMENTED.
+        var mode = Environment.GetEnvironmentVariable("SHARPEMU_BTHID_CB_FAIL");
+        if (string.Equals(mode, "nf", StringComparison.OrdinalIgnoreCase))
+        {
+            return ctx.SetReturn((int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND);
+        }
+
+        if (string.Equals(mode, "ni", StringComparison.OrdinalIgnoreCase))
+        {
+            return ctx.SetReturn((int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_IMPLEMENTED);
+        }
+
+        return Result(ctx);
+    }
+
+    private static void FireEnumerationComplete(CpuContext ctx)
+    {
+        var scheduler = GuestThreadExecution.Scheduler;
+        if (scheduler is null)
+        {
+            return;
+        }
+
+        var eventCode = ParseEnvUInt64("SHARPEMU_BTHID_EVENT_CODE", 0);
+        var eventSize = (int)ParseEnvUInt64("SHARPEMU_BTHID_EVENT_SIZE", 256);
+        if (eventSize < 1)
+        {
+            eventSize = 256;
+        }
+
+        // Leaked by design: the guest may retain the pointer past the callback.
+        var eventStruct = Marshal.AllocHGlobal(eventSize);
+        for (var offset = 0; offset < eventSize; offset++)
+        {
+            Marshal.WriteByte(eventStruct, offset, 0);
+        }
+
+        Console.Error.WriteLine(
+            $"[BTHID][EXPERIMENT] firing callback=0x{_callbackFunction:X} code={eventCode} size={eventSize} struct=0x{eventStruct.ToInt64():X}");
+        if (!scheduler.TryCallGuestFunction(
+                ctx,
+                _callbackFunction,
+                unchecked((ulong)eventStruct.ToInt64()),
+                eventCode,
+                0,
+                0,
+                "sceBluetoothHid synthetic enumeration event",
+                out var error))
+        {
+            Console.Error.WriteLine($"[BTHID][EXPERIMENT] callback failed: {error}");
+        }
+        else
+        {
+            Console.Error.WriteLine("[BTHID][EXPERIMENT] callback returned OK");
+        }
+    }
+
+    private static ulong ParseEnvUInt64(string name, ulong fallback)
+    {
+        var value = Environment.GetEnvironmentVariable(name);
+        if (string.IsNullOrWhiteSpace(value))
+        {
+            return fallback;
+        }
+
+        value = value.Trim();
+        var hex = value.StartsWith("0x", StringComparison.OrdinalIgnoreCase);
+        return ulong.TryParse(
+            hex ? value[2..] : value,
+            hex ? System.Globalization.NumberStyles.HexNumber : System.Globalization.NumberStyles.Integer,
+            null,
+            out var parsed) ? parsed : fallback;
+    }
 }

src/SharpEmu.Libs/Pad/HostWindowInput.cs

@@ -253,9 +253,9 @@ public static class HostWindowInput
         };
     }
 
-    private static byte ToStickByte(float value)
+    internal static byte ToStickByte(float value)
     {
-        return (byte)Math.Clamp((int)(128.0f + value * 127.0f), 0, 255);
+        return (byte)Math.Clamp((int)MathF.Round((value + 1.0f) * 127.5f), 0, 255);
     }
 
     private static HostGamepadButtons MapButton(ButtonName name) => name switch

src/SharpEmu.Libs/Pad/PadExports.cs

@@ -23,6 +23,11 @@ public static class PadExports
     private const int PrimaryPadHandle = 1;
     private const int ControllerInformationSize = 0x1C;
     private const int PadDataSize = 0x78;
+
+    // Real firmware hands out small non-negative handles; 0 is valid. Some titles
+    // (Monster Truck Championship) read pad state with handle 0, and rejecting it
+    // leaves their controller/FFB init path polling a never-valid state forever.
+    private static bool IsPrimaryPadHandle(int handle) => handle is 0 or PrimaryPadHandle;
     private static readonly long InputSampleIntervalTicks = Math.Max(1, Stopwatch.Frequency / 1000);
 
     [ThreadStatic]
@@ -104,7 +109,7 @@ public static class PadExports
     public static int PadClose(CpuContext ctx)
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
-        return handle == PrimaryPadHandle
+        return IsPrimaryPadHandle(handle)
             ? ctx.SetReturn(0)
             : ctx.SetReturn(OrbisPadErrorInvalidHandle);
     }
@@ -117,7 +122,7 @@ public static class PadExports
     public static int PadSetMotionSensorState(CpuContext ctx)
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
-        return handle == PrimaryPadHandle
+        return IsPrimaryPadHandle(handle)
             ? ctx.SetReturn(0)
             : ctx.SetReturn(OrbisPadErrorInvalidHandle);
     }
@@ -131,7 +136,7 @@ public static class PadExports
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
         var informationAddress = ctx[CpuRegister.Rsi];
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }
@@ -166,7 +171,7 @@ public static class PadExports
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
         var informationAddress = ctx[CpuRegister.Rsi];
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }
@@ -207,7 +212,7 @@ public static class PadExports
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
         var dataAddress = ctx[CpuRegister.Rsi];
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }
@@ -232,7 +237,7 @@ public static class PadExports
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
         var dataAddress = ctx[CpuRegister.Rsi];
         var count = unchecked((int)ctx[CpuRegister.Rdx]);
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }
@@ -266,7 +271,7 @@ public static class PadExports
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
         var parameterAddress = ctx[CpuRegister.Rsi];
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }
@@ -310,7 +315,7 @@ public static class PadExports
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
         var parameterAddress = ctx[CpuRegister.Rsi];
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }
@@ -340,7 +345,7 @@ public static class PadExports
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
         var parameterAddress = ctx[CpuRegister.Rsi];
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }
@@ -369,7 +374,7 @@ public static class PadExports
     public static int PadResetLightBar(CpuContext ctx)
     {
         var handle = unchecked((int)ctx[CpuRegister.Rdi]);
-        if (handle != PrimaryPadHandle)
+        if (!IsPrimaryPadHandle(handle))
         {
             return ctx.SetReturn(OrbisPadErrorInvalidHandle);
         }

src/SharpEmu.Libs/PlayGo/PlayGoExports.cs

@@ -4,6 +4,7 @@
 using SharpEmu.HLE;
 using System.Buffers.Binary;
 using System.Text.RegularExpressions;
+using System.Xml.Linq;
 
 namespace SharpEmu.Libs.PlayGo;
 
@@ -418,12 +419,21 @@ public static class PlayGoExports
                         $"[LOADER][TRACE] playgo.unknown_chunk_id id={chunkId} entries={numberOfEntries} " +
                         $"known=[{string.Join(',', knownChunkIds)}]");
                 }
+
+                // Real firmware rejects chunk ids outside the package's chunk set.
+                // Titles rely on this as an enumeration terminator: Monster Truck
+                // scans ids 0,1,2,... until BAD_CHUNK_ID, and answering OK for every
+                // id makes that scan wrap the ushort range and spin forever.
+                loci[i] = PlayGoLocusNotDownloaded;
+                return ctx.Memory.TryWrite(outLoci, loci)
+                    ? OrbisPlayGoErrorBadChunkId
+                    : (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT;
             }
 
             loci[i] = PlayGoLocusLocalFast;
         }
 
-        TracePlayGoLocus(numberOfEntries, chunkIds, outLoci);
+        TracePlayGoLocus(ctx, numberOfEntries, chunkIds, outLoci);
         return ctx.Memory.TryWrite(outLoci, loci)
             ? (int)OrbisGen2Result.ORBIS_GEN2_OK
             : (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT;
@@ -663,7 +673,8 @@ public static class PlayGoExports
     {
         lock (_stateGate)
         {
-            return _metadata.ChunkIds.Length == 0 || Array.BinarySearch(_metadata.ChunkIds, chunkId) >= 0;
+            return _metadata.ChunkIdKnowledge == PlayGoChunkIdKnowledge.Unknown ||
+                Array.BinarySearch(_metadata.ChunkIds, chunkId) >= 0;
         }
     }
 
@@ -672,7 +683,12 @@ public static class PlayGoExports
         var app0Root = Environment.GetEnvironmentVariable("SHARPEMU_APP0_DIR");
         if (string.IsNullOrWhiteSpace(app0Root))
         {
-            return PlayGoMetadata.Empty;
+            // No app0 override to probe for sidecar files: same fully-installed
+            // single-chunk fallback as below, or scePlayGoOpen fails fatally.
+            return new PlayGoMetadata(
+                true,
+                [(ushort)0],
+                PlayGoChunkIdKnowledge.Authoritative);
         }
 
         var playGoDat = Path.Combine(app0Root, "sce_sys", "playgo-chunk.dat");
@@ -682,13 +698,24 @@ public static class PlayGoExports
         var hasMetadata = File.Exists(playGoDat) || File.Exists(scenarioJson) || File.Exists(chunkDefsXml);
         if (!hasMetadata)
         {
-            // Full installs may omit PlayGo sidecar metadata.
-            TracePlayGo("metadata_missing; using fully-installed default chunk");
-            return new PlayGoMetadata(true, [(ushort)0]);
+            // No PlayGo sidecar: report a fully-installed single chunk. Available must
+            // stay true or scePlayGoOpen fails with NotSupportPlayGo (fatal PS5-component
+            // init failure for UE titles); chunk 0 reports LocalFast and every other id
+            // returns BAD_CHUNK_ID, terminating title-side chunk enumeration.
+            TracePlayGo("metadata_missing; fully-installed single chunk");
+            return new PlayGoMetadata(
+                true,
+                [(ushort)0],
+                PlayGoChunkIdKnowledge.Authoritative);
         }
 
         var chunkIds = LoadChunkIds(chunkDefsXml);
-        return new PlayGoMetadata(true, chunkIds);
+        return new PlayGoMetadata(
+            true,
+            chunkIds,
+            chunkIds.Length == 0
+                ? PlayGoChunkIdKnowledge.Unknown
+                : PlayGoChunkIdKnowledge.Authoritative);
     }
 
     private static ushort[] LoadChunkIds(string chunkDefsXml)
@@ -701,6 +728,8 @@ public static class PlayGoExports
         try
         {
             var xml = File.ReadAllText(chunkDefsXml);
+            _ = XDocument.Parse(xml, LoadOptions.None);
+
             var chunkIds = new HashSet<ushort>();
             AddChunkIds(xml, DefaultChunkPattern, chunkIds);
             AddChunkIds(xml, ChunkIdPattern, chunkIds);
@@ -717,6 +746,10 @@ public static class PlayGoExports
         {
             return Array.Empty<ushort>();
         }
+        catch (System.Xml.XmlException)
+        {
+            return Array.Empty<ushort>();
+        }
     }
 
     private static void AddChunkIds(string xml, Regex pattern, HashSet<ushort> chunkIds)
@@ -738,7 +771,7 @@ public static class PlayGoExports
         }
     }
 
-    private static void TracePlayGoLocus(uint entries, ulong chunkIds, ulong outLoci)
+    private static void TracePlayGoLocus(CpuContext ctx, uint entries, ulong chunkIds, ulong outLoci)
     {
         if (!string.Equals(Environment.GetEnvironmentVariable("SHARPEMU_LOG_PLAYGO"), "1", StringComparison.Ordinal))
         {
@@ -748,13 +781,42 @@ public static class PlayGoExports
         var count = Interlocked.Increment(ref _locusTraceDiagnostics);
         if (entries != 1 || count <= 32 || count % 1000 == 0)
         {
+            _ = ctx.TryReadUInt16(chunkIds, out var firstChunkId);
             Console.Error.WriteLine(
-                $"[LOADER][TRACE] playgo.get_locus entries={entries} chunk_ids=0x{chunkIds:X16} out=0x{outLoci:X16}");
+                $"[LOADER][TRACE] playgo.get_locus entries={entries} first_chunk={firstChunkId} " +
+                $"chunk_ids=0x{chunkIds:X16} out=0x{outLoci:X16}");
         }
     }
 
-    private sealed record PlayGoMetadata(bool Available, ushort[] ChunkIds)
+    internal static void ResetForTests()
     {
-        public static readonly PlayGoMetadata Empty = new(false, Array.Empty<ushort>());
+        lock (_stateGate)
+        {
+            _initialized = false;
+            _opened = false;
+            _metadata = PlayGoMetadata.Empty;
+            _installSpeed = PlayGoInstallSpeedTrickle;
+            _languageMask = ulong.MaxValue;
+        }
+
+        Interlocked.Exchange(ref _unknownChunkDiagnostics, 0);
+        Interlocked.Exchange(ref _locusTraceDiagnostics, 0);
+    }
+
+    private enum PlayGoChunkIdKnowledge
+    {
+        Unknown,
+        Authoritative,
+    }
+
+    private sealed record PlayGoMetadata(
+        bool Available,
+        ushort[] ChunkIds,
+        PlayGoChunkIdKnowledge ChunkIdKnowledge)
+    {
+        public static readonly PlayGoMetadata Empty = new(
+            false,
+            Array.Empty<ushort>(),
+            PlayGoChunkIdKnowledge.Unknown);
     }
 }

src/SharpEmu.Libs/Rtc/RtcExports.cs

@@ -241,6 +241,64 @@ public static class RtcExports
         LibraryName = "libSceRtc")]
     public static int RtcGetCurrentRawNetworkTick(CpuContext ctx) => RtcGetCurrentTick(ctx);
 
+    // Diagnostic: middleware busy-wait loops typically poll sceRtcGetCurrentTick, so the
+    // caller's return address pinpoints the loop. SHARPEMU_RTC_PROBE_RANGE=<start>-<end>
+    // (hex guest addresses) dumps 0x100 bytes of code around the first matching caller,
+    // once, for offline disassembly. Costs nothing when the variable is unset.
+    private static readonly ulong[]? _rtcProbeRange = ParseRtcProbeRange();
+    private static int _rtcProbeDone;
+
+    private static ulong[]? ParseRtcProbeRange()
+    {
+        var value = Environment.GetEnvironmentVariable("SHARPEMU_RTC_PROBE_RANGE");
+        if (string.IsNullOrWhiteSpace(value))
+        {
+            return null;
+        }
+
+        var parts = value.Split('-', 2, StringSplitOptions.TrimEntries);
+        return parts.Length == 2 &&
+               TryParseHexAddress(parts[0], out var start) &&
+               TryParseHexAddress(parts[1], out var end) &&
+               start < end
+            ? [start, end]
+            : null;
+    }
+
+    private static bool TryParseHexAddress(string value, out ulong address)
+    {
+        if (value.StartsWith("0x", StringComparison.OrdinalIgnoreCase))
+        {
+            value = value[2..];
+        }
+
+        return ulong.TryParse(
+            value,
+            System.Globalization.NumberStyles.HexNumber,
+            null,
+            out address);
+    }
+
+    private static void ProbeRtcCaller(CpuContext ctx)
+    {
+        if (Volatile.Read(ref _rtcProbeDone) != 0 ||
+            !ctx.TryReadUInt64(ctx[CpuRegister.Rsp], out var ret) ||
+            ret < _rtcProbeRange![0] ||
+            ret >= _rtcProbeRange[1] ||
+            Interlocked.CompareExchange(ref _rtcProbeDone, 1, 0) != 0)
+        {
+            return;
+        }
+
+        var start = ret - 0x60;
+        Span<byte> code = stackalloc byte[0x100];
+        if (ctx.Memory.TryRead(start, code))
+        {
+            Console.Error.WriteLine(
+                $"[LOADER][DIAG] rtc.caller_code ret=0x{ret:X} @0x{start:X}: {System.Convert.ToHexString(code)}");
+        }
+    }
+
     [SysAbiExport(
         Nid = "18B2NS1y9UU",
         ExportName = "sceRtcGetCurrentTick",
@@ -254,6 +312,11 @@ public static class RtcExports
             return unchecked((int)0x80B50002);
         }
 
+        if (_rtcProbeRange is not null)
+        {
+            ProbeRtcCaller(ctx);
+        }
+
         var tickValue = unchecked((ulong)(DateTime.UtcNow.Ticks / DateTimeTicksPerMicrosecond));
         if (!ctx.TryWriteUInt64(tickAddress, tickValue))
         {

src/SharpEmu.Libs/SystemService/SystemServiceExports.cs

@@ -15,6 +15,62 @@ public static class SystemServiceExports
     private const int DisplaySafeAreaInfoSize = sizeof(float) + 128;
     private const int HdrToneMapLuminanceSize = sizeof(float) * 3;
 
+    private const int TitleIdFieldSize = 0x10;
+
+    private static string? _mainAppTitleId;
+
+    public static void ConfigureApplicationInfo(string? titleId)
+    {
+        _mainAppTitleId = string.IsNullOrWhiteSpace(titleId) ? null : titleId.Trim();
+    }
+
+    [SysAbiExport(
+        Nid = "3RQ5aQfnstU",
+        ExportName = "sceSystemServiceGetNoticeScreenSkipFlag",
+        Target = Generation.Gen5,
+        LibraryName = "libSceSystemService")]
+    public static int SystemServiceGetNoticeScreenSkipFlag(CpuContext ctx)
+    {
+        var flagAddress = ctx[CpuRegister.Rdi];
+        if (flagAddress == 0)
+        {
+            return ctx.SetReturn(OrbisSystemServiceErrorParameter);
+        }
+
+        // No system notice screen to skip in the emulator; report "do not skip".
+        Span<byte> flagBytes = stackalloc byte[sizeof(int)];
+        BinaryPrimitives.WriteInt32LittleEndian(flagBytes, 0);
+        return ctx.Memory.TryWrite(flagAddress, flagBytes)
+            ? ctx.SetReturn(0)
+            : ctx.SetReturn((int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT);
+    }
+
+    [SysAbiExport(
+        Nid = "4veE0XiIugA",
+        ExportName = "sceSystemServiceGetMainAppTitleId",
+        Target = Generation.Gen5,
+        LibraryName = "libSceSystemService")]
+    public static int SystemServiceGetMainAppTitleId(CpuContext ctx)
+    {
+        var titleIdAddress = ctx[CpuRegister.Rdi];
+        if (titleIdAddress == 0)
+        {
+            return ctx.SetReturn(OrbisSystemServiceErrorParameter);
+        }
+
+        // Title IDs are a fixed 9-char format written into a 0x10-byte field;
+        // bound the length so a malformed param.json cannot drive an unbounded
+        // stack allocation or overrun the guest buffer.
+        var titleId = _mainAppTitleId ?? "PPSA00000";
+        var length = Math.Min(titleId.Length, TitleIdFieldSize - 1);
+        Span<byte> titleIdBytes = stackalloc byte[TitleIdFieldSize];
+        titleIdBytes.Clear();
+        System.Text.Encoding.ASCII.GetBytes(titleId.AsSpan(0, length), titleIdBytes);
+        return ctx.Memory.TryWrite(titleIdAddress, titleIdBytes[..(length + 1)])
+            ? ctx.SetReturn(0)
+            : ctx.SetReturn((int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT);
+    }
+
     [SysAbiExport(
         Nid = "fZo48un7LK4",
         ExportName = "sceSystemServiceParamGetInt",

src/SharpEmu.Libs/VideoOut/VideoOutExports.cs

@@ -259,6 +259,22 @@ public static class VideoOutExports
         }
     }
 
+    [SysAbiExport(
+        Nid = "Nv8c-Kb+DUM",
+        ExportName = "sceVideoOutIsOutputSupported",
+        Target = Generation.Gen4 | Generation.Gen5,
+        LibraryName = "libSceVideoOut")]
+    public static int VideoOutIsOutputSupported(CpuContext ctx)
+    {
+        var busType = unchecked((int)ctx[CpuRegister.Rdi]);
+        _ = ctx[CpuRegister.Rsi]; // pixelFormat
+        _ = ctx[CpuRegister.Rdx]; // aspectRatio
+
+        // The emulator supports any output configuration on the main bus.
+        // Return 1 (supported) for SceVideoOutBusTypeMain, 0 otherwise.
+        return busType == SceVideoOutBusTypeMain ? 1 : 0;
+    }
+
     [SysAbiExport(
         Nid = "uquVH4-Du78",
         ExportName = "sceVideoOutClose",

src/SharpEmu.Libs/VideoOut/VulkanHostBufferPool.cs

@@ -0,0 +1,109 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using Silk.NET.Vulkan;
+using VkBuffer = Silk.NET.Vulkan.Buffer;
+
+namespace SharpEmu.Libs.VideoOut;
+
+internal readonly record struct VulkanHostBufferPoolKey(
+    BufferUsageFlags Usage,
+    ulong Capacity);
+
+internal readonly record struct VulkanHostBufferAllocation(
+    VkBuffer Buffer,
+    DeviceMemory Memory,
+    VulkanHostBufferPoolKey Key,
+    nint Mapped);
+
+internal sealed class VulkanHostBufferPool : IDisposable
+{
+    private readonly Dictionary<VulkanHostBufferPoolKey, Stack<VulkanHostBufferAllocation>>
+        _available = [];
+    private readonly Dictionary<ulong, VulkanHostBufferAllocation> _allocations = [];
+    private readonly HashSet<ulong> _cachedHandles = [];
+    private readonly Action<VulkanHostBufferAllocation> _destroy;
+
+    public VulkanHostBufferPool(
+        ulong maximumCachedBytes,
+        Action<VulkanHostBufferAllocation> destroy)
+    {
+        MaximumCachedBytes = maximumCachedBytes;
+        _destroy = destroy;
+    }
+
+    public ulong MaximumCachedBytes { get; }
+
+    public ulong CachedBytes { get; private set; }
+
+    public bool TryRent(
+        VulkanHostBufferPoolKey key,
+        out VulkanHostBufferAllocation allocation)
+    {
+        if (!_available.TryGetValue(key, out var available) ||
+            !available.TryPop(out allocation))
+        {
+            allocation = default;
+            return false;
+        }
+
+        _cachedHandles.Remove(allocation.Buffer.Handle);
+        CachedBytes -= allocation.Key.Capacity;
+        return true;
+    }
+
+    public void Register(VulkanHostBufferAllocation allocation)
+    {
+        if (allocation.Buffer.Handle == 0)
+        {
+            throw new ArgumentException("A pooled buffer must have a valid handle.", nameof(allocation));
+        }
+
+        _allocations.Add(allocation.Buffer.Handle, allocation);
+    }
+
+    public bool Return(VkBuffer buffer, DeviceMemory memory)
+    {
+        if (!_allocations.TryGetValue(buffer.Handle, out var allocation) ||
+            allocation.Memory.Handle != memory.Handle)
+        {
+            return false;
+        }
+
+        if (!_cachedHandles.Add(buffer.Handle))
+        {
+            return true;
+        }
+
+        if (allocation.Key.Capacity > MaximumCachedBytes - CachedBytes)
+        {
+            _cachedHandles.Remove(buffer.Handle);
+            _allocations.Remove(buffer.Handle);
+            _destroy(allocation);
+            return true;
+        }
+
+        if (!_available.TryGetValue(allocation.Key, out var available))
+        {
+            available = [];
+            _available.Add(allocation.Key, available);
+        }
+
+        available.Push(allocation);
+        CachedBytes += allocation.Key.Capacity;
+        return true;
+    }
+
+    public void Dispose()
+    {
+        foreach (var allocation in _allocations.Values)
+        {
+            _destroy(allocation);
+        }
+
+        _allocations.Clear();
+        _available.Clear();
+        _cachedHandles.Clear();
+        CachedBytes = 0;
+    }
+}

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.cs

@@ -124,6 +124,7 @@ internal static unsafe class VulkanVideoPresenter
     // stays tighter than the drain budget because queued draws pin their
     // pooled guest-data arrays until the render thread uploads them.
     private const int MaxPendingGuestWork = 64;
+    private const ulong MaximumCachedHostBufferBytes = 128UL * 1024 * 1024;
     // A captured 4K flip can consume tens of MiB of device-local memory.
     // Retain only a short presentation queue while always preserving the
     // newest generation; older immutable versions are retired immediately.
@@ -608,6 +609,42 @@ internal static unsafe class VulkanVideoPresenter
             shaderAddress);
     }
 
+    // Manual scans (targets are <= 8) so the per-draw validation does not
+    // allocate LINQ iterators/closures or a Distinct HashSet.
+    private static bool AnyRenderTargetInvalid(IReadOnlyList<GuestRenderTarget> targets)
+    {
+        foreach (var target in targets)
+        {
+            if (target.Address == 0 || target.Width == 0 || target.Height == 0)
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private static bool RenderTargetsMismatchedOrAliased(IReadOnlyList<GuestRenderTarget> targets, GuestRenderTarget first)
+    {
+        for (var i = 0; i < targets.Count; i++)
+        {
+            if (targets[i].Width != first.Width || targets[i].Height != first.Height)
+            {
+                return true;
+            }
+
+            for (var j = i + 1; j < targets.Count; j++)
+            {
+                if (targets[i].Address == targets[j].Address)
+                {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
     public static void SubmitOffscreenTranslatedDraw(
         byte[] pixelSpirv,
         IReadOnlyList<GuestDrawTexture> textures,
@@ -627,16 +664,13 @@ internal static unsafe class VulkanVideoPresenter
         if (pixelSpirv.Length == 0 ||
             targets.Count == 0 ||
             targets.Count > 8 ||
-            targets.Any(target =>
-                target.Address == 0 || target.Width == 0 || target.Height == 0))
+            AnyRenderTargetInvalid(targets))
         {
             return;
         }
 
         var firstTarget = targets[0];
-        if (targets.Any(target =>
-                target.Width != firstTarget.Width || target.Height != firstTarget.Height) ||
-            targets.Select(target => target.Address).Distinct().Count() != targets.Count)
+        if (RenderTargetsMismatchedOrAliased(targets, firstTarget))
         {
             Console.Error.WriteLine(
                 "[LOADER][WARN] Vulkan skipped MRT draw with mismatched dimensions or aliased targets.");
@@ -654,9 +688,11 @@ internal static unsafe class VulkanVideoPresenter
         var effectiveRenderState = renderState ?? GuestRenderState.Default;
         if (effectiveRenderState.Blends.Count == 1 && targets.Count > 1)
         {
+            var broadcastBlends = new GuestBlendState[targets.Count];
+            Array.Fill(broadcastBlends, effectiveRenderState.Blends[0]);
             effectiveRenderState = effectiveRenderState with
             {
-                Blends = Enumerable.Repeat(effectiveRenderState.Blends[0], targets.Count).ToArray(),
+                Blends = broadcastBlends,
             };
         }
         lock (_gate)
@@ -2357,9 +2393,7 @@ internal static unsafe class VulkanVideoPresenter
             new(ReferenceEqualityComparer.Instance);
         private readonly Dictionary<DescriptorLayoutKey, DescriptorLayoutBundle>
             _descriptorLayouts = new();
-        private readonly Dictionary<HostBufferPoolKey, Stack<HostBufferAllocation>>
-            _hostBufferPool = new();
-        private readonly Dictionary<ulong, HostBufferAllocation> _hostBufferAllocations = new();
+        private readonly VulkanHostBufferPool _hostBufferPool;
         private readonly List<GuestBufferAllocation> _guestBufferAllocations = [];
         private readonly Queue<PendingGuestSubmission> _pendingGuestSubmissions = new();
         private readonly Dictionary<string, ulong> _lastSubmittedTimelineByGuestQueue =
@@ -2381,10 +2415,6 @@ internal static unsafe class VulkanVideoPresenter
             GuestRasterState Raster,
             GuestDepthState Depth);
 
-        private readonly record struct HostBufferPoolKey(
-            BufferUsageFlags Usage,
-            ulong Capacity);
-
         private readonly record struct DescriptorLayoutKey(
             ShaderStageFlags Stages,
             string Resources);
@@ -2397,12 +2427,6 @@ internal static unsafe class VulkanVideoPresenter
             DescriptorSetLayout DescriptorSetLayout,
             PipelineLayout PipelineLayout);
 
-        private sealed record HostBufferAllocation(
-            VkBuffer Buffer,
-            DeviceMemory Memory,
-            HostBufferPoolKey Key,
-            nint Mapped);
-
         private readonly record struct DirtyGuestBufferRange(ulong Offset, ulong Length);
 
         private sealed class GuestBufferAllocation
@@ -2592,6 +2616,9 @@ internal static unsafe class VulkanVideoPresenter
 
         public Presenter(uint width, uint height)
         {
+            _hostBufferPool = new VulkanHostBufferPool(
+                MaximumCachedHostBufferBytes,
+                DestroyHostBufferAllocation);
             var options = WindowOptions.DefaultVulkan;
             options.Size = new Vector2D<int>((int)DefaultWindowWidth, (int)DefaultWindowHeight);
             options.Title = VideoOutExports.GetWindowTitle();
@@ -2646,6 +2673,12 @@ internal static unsafe class VulkanVideoPresenter
                 }
             }
 
+            if (PngSplashLoader.TryLoadIcon(out var iconPixels, out var iconWidth, out var iconHeight))
+            {
+                var icon = new RawImage((int)iconWidth, (int)iconHeight, iconPixels);
+                _window.SetWindowIcon(ref icon);
+            }
+
             WaitForRenderDocAttachIfRequested();
             _vk = Vk.GetApi();
             CreateInstance();
@@ -4154,6 +4187,48 @@ internal static unsafe class VulkanVideoPresenter
                 _submitTimeline;
         }
 
+        private void TransitionNewGuestImageToSampled(Image image, uint mipLevels)
+        {
+            var commandBuffer = AllocateGuestCommandBuffer();
+            var beginInfo = new CommandBufferBeginInfo
+            {
+                SType = StructureType.CommandBufferBeginInfo,
+                Flags = CommandBufferUsageFlags.OneTimeSubmitBit,
+            };
+            Check(
+                _vk.BeginCommandBuffer(commandBuffer, &beginInfo),
+                "vkBeginCommandBuffer(guest image init)");
+            var barrier = new ImageMemoryBarrier
+            {
+                SType = StructureType.ImageMemoryBarrier,
+                SrcAccessMask = 0,
+                DstAccessMask = AccessFlags.ShaderReadBit,
+                OldLayout = ImageLayout.Undefined,
+                NewLayout = ImageLayout.ShaderReadOnlyOptimal,
+                SrcQueueFamilyIndex = Vk.QueueFamilyIgnored,
+                DstQueueFamilyIndex = Vk.QueueFamilyIgnored,
+                Image = image,
+                SubresourceRange = ColorSubresourceRange(0, mipLevels),
+            };
+            _vk.CmdPipelineBarrier(
+                commandBuffer,
+                PipelineStageFlags.TopOfPipeBit,
+                PipelineStageFlags.AllCommandsBit,
+                0,
+                0,
+                null,
+                0,
+                null,
+                1,
+                &barrier);
+            Check(
+                _vk.EndCommandBuffer(commandBuffer),
+                "vkEndCommandBuffer(guest image init)");
+            // Same-queue submission order makes the transition visible to any
+            // later use of the image; no CPU-side wait is needed.
+            SubmitGuestCommandBuffer(commandBuffer, [], []);
+        }
+
         private void EnsureGuestSubmissionCapacity()
         {
             CollectCompletedGuestSubmissions(waitForOldest: false);
@@ -4214,23 +4289,43 @@ internal static unsafe class VulkanVideoPresenter
                     return;
                 }
 
-                Check(result, $"vkWaitForFences(guest: {oldest.DebugName})");
+                if (result == Result.ErrorDeviceLost)
+                {
+                    _deviceLost = true;
+                }
+                else
+                {
+                    Check(result, $"vkWaitForFences(guest: {oldest.DebugName})");
+                }
             }
 
             while (_pendingGuestSubmissions.TryPeek(out var submission))
             {
                 var status = _vk.GetFenceStatus(_device, submission.Fence);
-                if (status == Result.NotReady)
+                if (status == Result.NotReady && !_deviceLost)
                 {
                     break;
                 }
 
-                Check(status, $"vkGetFenceStatus(guest: {submission.DebugName})");
+                if (status == Result.ErrorDeviceLost)
+                {
+                    // Pending fences never signal on a lost device; retire the
+                    // submission anyway so teardown and back-pressure survive.
+                    _deviceLost = true;
+                }
+                else if (status != Result.NotReady)
+                {
+                    Check(status, $"vkGetFenceStatus(guest: {submission.DebugName})");
+                }
+
                 _pendingGuestSubmissions.Dequeue();
 
-                foreach (var image in submission.TraceImages)
+                if (!_deviceLost)
                 {
-                    TraceGuestImageContents(image);
+                    foreach (var image in submission.TraceImages)
+                    {
+                        TraceGuestImageContents(image);
+                    }
                 }
 
                 foreach (var resources in submission.Resources)
@@ -4508,13 +4603,20 @@ internal static unsafe class VulkanVideoPresenter
                 $"queue={_activeGuestQueue.Name} submission={_activeGuestQueue.SubmissionId} " +
                 $"handle={work.VideoOutHandle} index={work.DisplayBufferIndex} " +
                 $"capture_complete={(captured ? 1 : 0)}");
-#if DEBUG
-            System.Diagnostics.Debug.Assert(
-                work.Version == 0 || captured,
-                "An ordered wait-safe marker must execute after its flip capture.");
-#endif
+            // Demon's Souls executes wait-safe markers before their flip capture;
+            // an assert here would fail-fast the process, so warn once instead.
+            // Dedup on a flag, not the (per-frame-unique) version, to bound growth.
+            if (work.Version != 0 && !captured && !_loggedFlipWaitOrderViolation)
+            {
+                _loggedFlipWaitOrderViolation = true;
+                Console.Error.WriteLine(
+                    $"[LOADER][WARN] vk.flip_wait_order version={work.Version} " +
+                    "executed before its flip capture; continuing.");
+            }
         }
 
+        private bool _loggedFlipWaitOrderViolation;
+
         private GuestImageResource CreateGuestFlipSnapshot(
             GuestImageResource source,
             long version)
@@ -5241,7 +5343,8 @@ internal static unsafe class VulkanVideoPresenter
                     resources.IndexBuffer = CreateHostBuffer(
                         indexBuffer.Data.AsSpan(0, indexBuffer.Length),
                         BufferUsageFlags.IndexBufferBit,
-                        out resources.IndexMemory);
+                        out resources.IndexMemory,
+                        out _);
                     resources.Index32Bit = indexBuffer.Is32Bit;
                     if (indexBuffer.Pooled)
                     {
@@ -6764,7 +6867,8 @@ internal static unsafe class VulkanVideoPresenter
             var vkFormat = GetTextureFormat(texture.Format, texture.NumberType);
 
             var expectedSize = GetTextureByteCount(texture.Format, rowLength, height);
-            if (_tracedTextureUploads.Add((texture.Address, width, height, vkFormat)))
+            if (ShouldTraceVulkanResources() &&
+                _tracedTextureUploads.Add((texture.Address, width, height, vkFormat)))
             {
                 Console.Error.WriteLine(
                     $"[LOADER][TRACE] vk.texture addr=0x{texture.Address:X16} " +
@@ -7536,8 +7640,8 @@ internal static unsafe class VulkanVideoPresenter
             var buffer = CreateHostBuffer(
                 guestBuffer.Data.AsSpan(0, guestBuffer.Length),
                 BufferUsageFlags.StorageBufferBit,
-                out var memory);
-            var allocation = _hostBufferAllocations[buffer.Handle];
+                out var memory,
+                out var mapped);
             if (guestBuffer.Pooled)
             {
                 GuestDataPool.Return(guestBuffer.Data);
@@ -7550,7 +7654,7 @@ internal static unsafe class VulkanVideoPresenter
                 WriteBackToGuest = false,
                 Buffer = buffer,
                 Memory = memory,
-                Mapped = allocation.Mapped,
+                Mapped = mapped,
                 Offset = 0,
                 Size = (ulong)Math.Max(guestBuffer.Length, sizeof(uint)),
                 GuestOffset = 0,
@@ -7770,7 +7874,8 @@ internal static unsafe class VulkanVideoPresenter
             var buffer = CreateHostBuffer(
                 source,
                 BufferUsageFlags.VertexBufferBit,
-                out var memory);
+                out var memory,
+                out _);
             var size = (ulong)Math.Max(guestBuffer.Length, sizeof(uint));
             if (_setDebugUtilsObjectName is not null)
             {
@@ -7839,19 +7944,15 @@ internal static unsafe class VulkanVideoPresenter
         private VkBuffer CreateHostBuffer(
             ReadOnlySpan<byte> data,
             BufferUsageFlags usage,
-            out DeviceMemory memory)
+            out DeviceMemory memory,
+            out nint mapped)
         {
             var size = (ulong)Math.Max(data.Length, sizeof(uint));
             var capacity = BitOperations.RoundUpToPowerOf2(size);
-            var key = new HostBufferPoolKey(usage, capacity);
-            if (!_hostBufferPool.TryGetValue(key, out var available))
-            {
-                available = new Stack<HostBufferAllocation>();
-                _hostBufferPool.Add(key, available);
-            }
+            var key = new VulkanHostBufferPoolKey(usage, capacity);
 
-            HostBufferAllocation allocation;
-            if (available.TryPop(out var pooled))
+            VulkanHostBufferAllocation allocation;
+            if (_hostBufferPool.TryRent(key, out var pooled))
             {
                 allocation = pooled;
             }
@@ -7869,15 +7970,16 @@ internal static unsafe class VulkanVideoPresenter
                 Check(
                     _vk.MapMemory(_device, allocatedMemory, 0, capacity, 0, &persistentMapping),
                     "vkMapMemory(host persistent)");
-                allocation = new HostBufferAllocation(
+                allocation = new VulkanHostBufferAllocation(
                     buffer,
                     allocatedMemory,
                     key,
                     (nint)persistentMapping);
-                _hostBufferAllocations.Add(buffer.Handle, allocation);
+                _hostBufferPool.Register(allocation);
             }
 
             memory = allocation.Memory;
+            mapped = allocation.Mapped;
             fixed (byte* source = data)
             {
                 System.Buffer.MemoryCopy(
@@ -7897,10 +7999,8 @@ internal static unsafe class VulkanVideoPresenter
                 return;
             }
 
-            if (_hostBufferAllocations.TryGetValue(buffer.Handle, out var allocation) &&
-                allocation.Memory.Handle == memory.Handle)
+            if (_hostBufferPool.Return(buffer, memory))
             {
-                _hostBufferPool[allocation.Key].Push(allocation);
                 return;
             }
 
@@ -7911,6 +8011,13 @@ internal static unsafe class VulkanVideoPresenter
             }
         }
 
+        private void DestroyHostBufferAllocation(VulkanHostBufferAllocation allocation)
+        {
+            _vk.UnmapMemory(_device, allocation.Memory);
+            _vk.DestroyBuffer(_device, allocation.Buffer, null);
+            _vk.FreeMemory(_device, allocation.Memory, null);
+        }
+
         private static PrimitiveTopology GetPrimitiveTopology(uint primitiveType) =>
             primitiveType switch
             {
@@ -8294,7 +8401,7 @@ internal static unsafe class VulkanVideoPresenter
             return (properties.OptimalTilingFeatures & FormatFeatureFlags.ColorAttachmentBit) != 0;
         }
 
-        private static Format GetTextureFormat(uint format, uint numberType) =>
+        internal static Format GetTextureFormat(uint format, uint numberType) =>
             (format, numberType) switch
             {
                 (9, _) => Format.A2B10G10R10UnormPack32,
@@ -10164,6 +10271,9 @@ internal static unsafe class VulkanVideoPresenter
                 _vk.AllocateMemory(_device, &allocationInfo, null, out var memory),
                 "vkAllocateMemory(offscreen)");
             Check(_vk.BindImageMemory(_device, image, memory, 0), "vkBindImageMemory(offscreen)");
+            // Rendering and uploads only define the mips they touch; define the whole
+            // chain once so full-chain sampled binds never read Undefined layout.
+            TransitionNewGuestImageToSampled(image, mipLevels);
 
             var viewInfo = new ImageViewCreateInfo
             {
@@ -10931,7 +11041,7 @@ internal static unsafe class VulkanVideoPresenter
             return view;
         }
 
-        private static bool IsCompatibleViewFormat(Format imageFormat, Format viewFormat)
+        internal static bool IsCompatibleViewFormat(Format imageFormat, Format viewFormat)
         {
             if (imageFormat == viewFormat)
             {
@@ -10997,6 +11107,23 @@ internal static unsafe class VulkanVideoPresenter
         }
 
         private void Render(double _)
+        {
+            try
+            {
+                RenderCore();
+            }
+            catch (Exception exception)
+            {
+                // Device loss can strike between any two Vulkan calls in the frame;
+                // keep the window loop pumping instead of tearing the presenter down.
+                if (!TryMarkDeviceLost(exception))
+                {
+                    throw;
+                }
+            }
+        }
+
+        private void RenderCore()
         {
             if (Volatile.Read(ref _presenterCloseRequested))
             {
@@ -11010,6 +11137,18 @@ internal static unsafe class VulkanVideoPresenter
                 return;
             }
 
+            if (_deviceLost)
+            {
+                // Drain queued work so producers aren't back-pressured, then
+                // return without any Vulkan call (fences never signal post-loss).
+                while (TryTakeGuestWork(out var lostWork))
+                {
+                    CompleteGuestWork(lostWork);
+                }
+
+                return;
+            }
+
             // Reuse of a frame slot waits only on that slot's fence, keeping
             // up to MaxFramesInFlight frames pipelined between CPU and GPU.
             var frameSlot = _currentFrameSlot;
@@ -13592,13 +13731,7 @@ internal static unsafe class VulkanVideoPresenter
                 DestroyGuestBufferAllocation(allocation);
             }
             _guestBufferAllocations.Clear();
-            foreach (var allocation in _hostBufferAllocations.Values)
-            {
-                _vk.DestroyBuffer(_device, allocation.Buffer, null);
-                _vk.FreeMemory(_device, allocation.Memory, null);
-            }
-            _hostBufferAllocations.Clear();
-            _hostBufferPool.Clear();
+            _hostBufferPool.Dispose();
             foreach (var guestImage in _guestImages.Values)
             {
                 DestroyGuestImage(guestImage);
@@ -13830,20 +13963,38 @@ internal static unsafe class VulkanVideoPresenter
                 return;
             }
 
+            if (result == Result.ErrorDeviceLost)
+            {
+                throw new VulkanDeviceLostException(operation);
+            }
+
             throw new InvalidOperationException($"{operation} failed with {result}.");
         }
 
         private static void Check(Result result, string operation)
         {
+            if (result == Result.ErrorDeviceLost)
+            {
+                throw new VulkanDeviceLostException(operation);
+            }
+
             if (result != Result.Success)
             {
                 throw new InvalidOperationException($"{operation} failed with {result}.");
             }
         }
 
+        // Typed so the frame-boundary catch can recognize device loss without
+        // depending on the exact wording of the exception message.
+        private sealed class VulkanDeviceLostException(string operation)
+            : InvalidOperationException($"{operation} failed with {Result.ErrorDeviceLost}.");
+
         private bool TryMarkDeviceLost(Exception exception)
         {
-            if (!exception.Message.Contains(nameof(Result.ErrorDeviceLost), StringComparison.Ordinal))
+            // Prefer the typed signal; fall back to the message for losses that
+            // surface through other layers (e.g. Silk.NET bindings).
+            if (exception is not VulkanDeviceLostException &&
+                !exception.Message.Contains(nameof(Result.ErrorDeviceLost), StringComparison.Ordinal))
             {
                 return false;
             }

src/SharpEmu.ShaderCompiler.Vulkan/Gen5SpirvTranslator.cs

@@ -1802,24 +1802,6 @@ public static partial class Gen5SpirvTranslator
 
             switch (instruction.Opcode)
             {
-                case "DsAddU32":
-                {
-                    if (instruction.Sources.Count < 2)
-                    {
-                        error = "missing LDS atomic-add source";
-                        return false;
-                    }
-
-                    var address = GetRawSource(instruction, 0);
-                    _module.AddInstruction(
-                        SpirvOp.AtomicIAdd,
-                        _uintType,
-                        LdsPointer(address, control.Offset0),
-                        UInt(2), // Workgroup scope.
-                        UInt(0x108), // AcquireRelease | WorkgroupMemory.
-                        GetRawSource(instruction, 1));
-                    return true;
-                }
                 case "DsWriteB32":
                 {
                     if (instruction.Sources.Count < 2)
@@ -1964,6 +1946,11 @@ public static partial class Gen5SpirvTranslator
                     return true;
                 }
                 default:
+                    if (Gen5ShaderTranslator.IsDataShareAtomic(instruction.Opcode))
+                    {
+                        return TryEmitDataShareAtomic(instruction, control, out error);
+                    }
+
                     error = $"unsupported LDS opcode {instruction.Opcode}";
                     return false;
             }
@@ -2004,6 +1991,126 @@ public static partial class Gen5SpirvTranslator
             Store(pointer, selected);
         }
 
+        private bool TryEmitDataShareAtomic(
+            Gen5ShaderInstruction instruction,
+            Gen5DataShareControl control,
+            out string error)
+        {
+            error = string.Empty;
+            var atomicOp = instruction.Opcode switch
+            {
+                "DsAddU32" or "DsAddRtnU32" => SpirvOp.AtomicIAdd,
+                "DsSubU32" or "DsSubRtnU32" => SpirvOp.AtomicISub,
+                "DsIncU32" or "DsIncRtnU32" => SpirvOp.AtomicIIncrement,
+                "DsDecU32" or "DsDecRtnU32" => SpirvOp.AtomicIDecrement,
+                "DsMinI32" or "DsMinRtnI32" => SpirvOp.AtomicSMin,
+                "DsMaxI32" or "DsMaxRtnI32" => SpirvOp.AtomicSMax,
+                "DsMinU32" or "DsMinRtnU32" => SpirvOp.AtomicUMin,
+                "DsMaxU32" or "DsMaxRtnU32" => SpirvOp.AtomicUMax,
+                "DsAndB32" or "DsAndRtnB32" => SpirvOp.AtomicAnd,
+                "DsOrB32" or "DsOrRtnB32" => SpirvOp.AtomicOr,
+                "DsXorB32" or "DsXorRtnB32" => SpirvOp.AtomicXor,
+                "DsWrxchgRtnB32" => SpirvOp.AtomicExchange,
+                "DsCmpstB32" or "DsCmpstRtnB32" => SpirvOp.AtomicCompareExchange,
+                _ => SpirvOp.Nop,
+            };
+            if (atomicOp == SpirvOp.Nop)
+            {
+                error = $"unsupported LDS opcode {instruction.Opcode}";
+                return false;
+            }
+
+            var address = GetRawSource(instruction, 0);
+            var pointer = LdsPointer(address, control.Offset0);
+            EmitExecConditional(() =>
+            {
+                var original = EmitAtomic(
+                    atomicOp,
+                    _uintType,
+                    pointer,
+                    scope: 2,
+                    semantics: 0x108,
+                    // DS_CMPST sources: DATA0 is the comparator, DATA1 the new value.
+                    value: () => GetRawSource(
+                        instruction,
+                        atomicOp == SpirvOp.AtomicCompareExchange ? 2 : 1),
+                    comparator: () => GetRawSource(instruction, 1));
+                if (instruction.Destinations.Count > 0)
+                {
+                    StoreV(instruction.Destinations[0].Value, original);
+                }
+            });
+
+            return true;
+        }
+
+        // Maps the AMD atomic-op name suffix shared by buffer/image atomics to a SPIR-V opcode.
+        // Inc/Dec approximate the AMD wrap-clamp semantics (MEM = tmp >= DATA ? 0 : tmp + 1),
+        // which is exact for the common 0xFFFFFFFF clamp operand.
+        private static bool TryGetAtomicOp(string name, out SpirvOp op)
+        {
+            op = name switch
+            {
+                "Swap" => SpirvOp.AtomicExchange,
+                "Cmpswap" => SpirvOp.AtomicCompareExchange,
+                "Add" => SpirvOp.AtomicIAdd,
+                "Sub" => SpirvOp.AtomicISub,
+                "Smin" => SpirvOp.AtomicSMin,
+                "Umin" => SpirvOp.AtomicUMin,
+                "Smax" => SpirvOp.AtomicSMax,
+                "Umax" => SpirvOp.AtomicUMax,
+                "And" => SpirvOp.AtomicAnd,
+                "Or" => SpirvOp.AtomicOr,
+                "Xor" => SpirvOp.AtomicXor,
+                "Inc" => SpirvOp.AtomicIIncrement,
+                "Dec" => SpirvOp.AtomicIDecrement,
+                _ => SpirvOp.Nop,
+            };
+            return op != SpirvOp.Nop;
+        }
+
+        private uint EmitAtomic(
+            SpirvOp op,
+            uint type,
+            uint pointer,
+            uint scope,
+            uint semantics,
+            Func<uint> value,
+            Func<uint> comparator)
+        {
+            if (op is SpirvOp.AtomicIIncrement or SpirvOp.AtomicIDecrement)
+            {
+                return _module.AddInstruction(
+                    op,
+                    type,
+                    pointer,
+                    UInt(scope),
+                    UInt(semantics));
+            }
+
+            if (op == SpirvOp.AtomicCompareExchange)
+            {
+                // The unequal semantics must not contain Release; downgrade it to Acquire.
+                return _module.AddInstruction(
+                    op,
+                    type,
+                    pointer,
+                    UInt(scope),
+                    UInt(semantics),
+                    UInt((semantics & ~0x8u) | 0x2u),
+                    value(),
+                    comparator());
+            }
+
+            return _module.AddInstruction(
+                op,
+                type,
+                pointer,
+                UInt(scope),
+                UInt(semantics),
+                value());
+        }
+
         private bool TryEmitInterpolation(
             Gen5ShaderInstruction instruction,
             Gen5InterpolationControl interpolation,
@@ -2239,22 +2346,27 @@ public static partial class Gen5SpirvTranslator
             byteAddress = ApplyGuestBufferByteBias(bindingIndex, byteAddress);
             var dwordAddress = ShiftRightLogical(byteAddress, UInt(2));
 
-            if (instruction.Opcode is "BufferAtomicAdd" or "BufferAtomicUMax")
+            if (instruction.Opcode.StartsWith("BufferAtomic", StringComparison.Ordinal))
             {
+                if (!TryGetAtomicOp(instruction.Opcode["BufferAtomic".Length..], out var atomicOp))
+                {
+                    error = $"unsupported buffer opcode {instruction.Opcode}";
+                    return false;
+                }
+
                 EmitExecConditional(() =>
                 {
                     var inRange = IsBufferWordInRange(bindingIndex, dwordAddress);
                     EmitConditional(inRange, () =>
                     {
-                        var original = _module.AddInstruction(
-                            instruction.Opcode == "BufferAtomicAdd"
-                                ? SpirvOp.AtomicIAdd
-                                : SpirvOp.AtomicUMax,
+                        var original = EmitAtomic(
+                            atomicOp,
                             _uintType,
                             BufferWordPointer(bindingIndex, dwordAddress),
-                            UInt(1),
-                            UInt(0x48),
-                            LoadV(control.VectorData));
+                            scope: 1,
+                            semantics: 0x48,
+                            value: () => LoadV(control.VectorData),
+                            comparator: () => LoadV(control.VectorData + 1));
                         if (control.Glc)
                         {
                             StoreV(control.VectorData, original);
@@ -3196,6 +3308,60 @@ public static partial class Gen5SpirvTranslator
                 return true;
             }
 
+            if (instruction.Opcode.StartsWith("ImageAtomic", StringComparison.Ordinal))
+            {
+                if (!resource.IsStorage)
+                {
+                    error = "image atomic is not bound as storage";
+                    return false;
+                }
+
+                if (resource.ComponentKind == ImageComponentKind.Float ||
+                    !TryGetAtomicOp(instruction.Opcode["ImageAtomic".Length..], out var atomicOp))
+                {
+                    error = $"unsupported storage image opcode {instruction.Opcode}";
+                    return false;
+                }
+
+                var signed = resource.ComponentKind == ImageComponentKind.Sint;
+                var atomicImageSize = _module.AddInstruction(
+                    SpirvOp.ImageQuerySize,
+                    _module.TypeVector(_intType, 2),
+                    imageObject);
+                var coordinates = BuildClampedIntegerCoordinates(
+                    image,
+                    0,
+                    atomicImageSize);
+                EmitExecConditional(() =>
+                {
+                    var pointer = _module.AddInstruction(
+                        SpirvOp.ImageTexelPointer,
+                        _module.TypePointer(SpirvStorageClass.Image, resource.ComponentType),
+                        resource.Variable,
+                        coordinates,
+                        UInt(0));
+                    uint LoadData(uint register) => signed
+                        ? Bitcast(_intType, LoadV(register))
+                        : LoadV(register);
+                    var original = EmitAtomic(
+                        atomicOp,
+                        resource.ComponentType,
+                        pointer,
+                        scope: 1,
+                        semantics: 0x808,
+                        value: () => LoadData(image.VectorData),
+                        comparator: () => LoadData(image.VectorData + 1));
+                    if (image.Glc)
+                    {
+                        StoreV(
+                            image.VectorData,
+                            signed ? Bitcast(_uintType, original) : original);
+                    }
+                });
+
+                return true;
+            }
+
             if (resource.IsStorage &&
                 instruction.Opcode is not ("ImageLoad" or "ImageLoadMip"))
             {

src/SharpEmu.ShaderCompiler.Vulkan/SpirvModuleBuilder.cs

@@ -40,6 +40,7 @@ public enum SpirvOp : ushort
     FunctionEnd = 56,
     FunctionCall = 57,
     Variable = 59,
+    ImageTexelPointer = 60,
     Load = 61,
     Store = 62,
     AccessChain = 65,
@@ -142,8 +143,19 @@ public enum SpirvOp : ushort
     BitCount = 205,
     ControlBarrier = 224,
     MemoryBarrier = 225,
+    AtomicExchange = 229,
+    AtomicCompareExchange = 230,
+    AtomicIIncrement = 232,
+    AtomicIDecrement = 233,
     AtomicIAdd = 234,
+    AtomicISub = 235,
+    AtomicSMin = 236,
+    AtomicUMin = 237,
+    AtomicSMax = 238,
     AtomicUMax = 239,
+    AtomicAnd = 240,
+    AtomicOr = 241,
+    AtomicXor = 242,
     Phi = 245,
     LoopMerge = 246,
     SelectionMerge = 247,

src/SharpEmu.ShaderCompiler/Gen5ShaderTranslator.cs

@@ -1172,9 +1172,33 @@ public static class Gen5ShaderTranslator
         name = opcode switch
         {
             0x00 => "DsAddU32",
+            0x01 => "DsSubU32",
+            0x03 => "DsIncU32",
+            0x04 => "DsDecU32",
+            0x05 => "DsMinI32",
+            0x06 => "DsMaxI32",
+            0x07 => "DsMinU32",
+            0x08 => "DsMaxU32",
+            0x09 => "DsAndB32",
+            0x0A => "DsOrB32",
+            0x0B => "DsXorB32",
             0x0D => "DsWriteB32",
             0x0E => "DsWrite2B32",
             0x0F => "DsWrite2St64B32",
+            0x10 => "DsCmpstB32",
+            0x20 => "DsAddRtnU32",
+            0x21 => "DsSubRtnU32",
+            0x23 => "DsIncRtnU32",
+            0x24 => "DsDecRtnU32",
+            0x25 => "DsMinRtnI32",
+            0x26 => "DsMaxRtnI32",
+            0x27 => "DsMinRtnU32",
+            0x28 => "DsMaxRtnU32",
+            0x29 => "DsAndRtnB32",
+            0x2A => "DsOrRtnB32",
+            0x2B => "DsXorRtnB32",
+            0x2D => "DsWrxchgRtnB32",
+            0x30 => "DsCmpstRtnB32",
             0x35 => "DsSwizzleB32",
             0x36 => "DsReadB32",
             0x37 => "DsRead2B32",
@@ -1272,8 +1296,19 @@ public static class Gen5ShaderTranslator
             0x23 => "BufferLoadSbyteD16Hi",
             0x24 => "BufferLoadShortD16",
             0x25 => "BufferLoadShortD16Hi",
+            0x30 => "BufferAtomicSwap",
+            0x31 => "BufferAtomicCmpswap",
             0x32 => "BufferAtomicAdd",
-            0x38 => "BufferAtomicUMax",
+            0x33 => "BufferAtomicSub",
+            0x35 => "BufferAtomicSmin",
+            0x36 => "BufferAtomicUmin",
+            0x37 => "BufferAtomicSmax",
+            0x38 => "BufferAtomicUmax",
+            0x39 => "BufferAtomicAnd",
+            0x3A => "BufferAtomicOr",
+            0x3B => "BufferAtomicXor",
+            0x3C => "BufferAtomicInc",
+            0x3D => "BufferAtomicDec",
             _ => $"MubufRaw{opcode:X2}",
         };
         sizeDwords = (extra >> 24) == 0xFF ? 3u : 2u;
@@ -1388,7 +1423,18 @@ public static class Gen5ShaderTranslator
             0x08 => "ImageStore",
             0x09 => "ImageStoreMip",
             0x0E => "ImageGetResinfo",
+            0x0F => "ImageAtomicSwap",
             0x10 => "ImageAtomicCmpswap",
+            0x11 => "ImageAtomicAdd",
+            0x12 => "ImageAtomicSub",
+            0x14 => "ImageAtomicSmin",
+            0x15 => "ImageAtomicUmin",
+            0x16 => "ImageAtomicSmax",
+            0x17 => "ImageAtomicUmax",
+            0x18 => "ImageAtomicAnd",
+            0x19 => "ImageAtomicOr",
+            0x1A => "ImageAtomicXor",
+            0x1B => "ImageAtomicInc",
             0x1C => "ImageAtomicDec",
             0x20 => "ImageSample",
             0x22 => "ImageSampleD",
@@ -1488,6 +1534,18 @@ public static class Gen5ShaderTranslator
         name.StartsWith("ImageStore", StringComparison.Ordinal) ||
         name.StartsWith("ImageAtomic", StringComparison.Ordinal);
 
+    public static bool IsDataShareAtomic(string name) => name switch
+    {
+        "DsAddU32" or "DsSubU32" or "DsIncU32" or "DsDecU32" or
+        "DsMinI32" or "DsMaxI32" or "DsMinU32" or "DsMaxU32" or
+        "DsAndB32" or "DsOrB32" or "DsXorB32" or "DsCmpstB32" or
+        "DsAddRtnU32" or "DsSubRtnU32" or "DsIncRtnU32" or "DsDecRtnU32" or
+        "DsMinRtnI32" or "DsMaxRtnI32" or "DsMinRtnU32" or "DsMaxRtnU32" or
+        "DsAndRtnB32" or "DsOrRtnB32" or "DsXorRtnB32" or
+        "DsWrxchgRtnB32" or "DsCmpstRtnB32" => true,
+        _ => false,
+    };
+
     private static Gen5ShaderInstruction CreateInstruction(
         uint pc,
         Gen5ShaderEncoding encoding,
@@ -1767,9 +1825,9 @@ public static class Gen5ShaderTranslator
                 destinations = [Gen5Operand.Vector(word & 0xFF)];
                 if (opcode == "VReadlaneB32")
                 {
-                    // VReadlaneB32 writes to scalar destination (bits 8-14), not vector.
-                    // Bits 0-7 are unused for this opcode.
-                    destinations = [Gen5Operand.Scalar((word >> 8) & 0x7F)];
+                    // The scalar destination lives in the low vdst byte (bits 0-7);
+                    // bits 8-14 are the VOP3B carry-out sdst, which readlane lacks.
+                    destinations = [Gen5Operand.Scalar(word & 0xFF)];
                 }
                 var isVop3B = IsVop3BOpcode((word >> 16) & 0x3FF);
                 control = new Gen5Vop3Control(
@@ -1794,10 +1852,6 @@ public static class Gen5ShaderTranslator
                     ((word >> 17) & 1) != 0);
                 sources = opcode switch
                 {
-                    "DsAddU32" => [
-                        Gen5Operand.Vector(vectorAddress),
-                        Gen5Operand.Vector(vectorData0),
-                    ],
                     "DsWriteB32" => [
                         Gen5Operand.Vector(vectorAddress),
                         Gen5Operand.Vector(vectorData0),
@@ -1826,6 +1880,17 @@ public static class Gen5ShaderTranslator
                         Gen5Operand.Vector(vectorData1),
                     ],
                     "DsSwizzleB32" => [Gen5Operand.Vector(vectorData0)],
+                    // DS_CMPST operand order is reversed vs buffer/image cmpswap:
+                    // DATA0 holds the comparator, DATA1 holds the new value.
+                    "DsCmpstB32" or "DsCmpstRtnB32" => [
+                        Gen5Operand.Vector(vectorAddress),
+                        Gen5Operand.Vector(vectorData0),
+                        Gen5Operand.Vector(vectorData1),
+                    ],
+                    _ when IsDataShareAtomic(opcode) => [
+                        Gen5Operand.Vector(vectorAddress),
+                        Gen5Operand.Vector(vectorData0),
+                    ],
                     _ => [Gen5Operand.Vector(vectorAddress)],
                 };
                 destinations = opcode switch
@@ -1848,6 +1913,10 @@ public static class Gen5ShaderTranslator
                         Gen5Operand.Vector(vectorDestination + 2),
                         Gen5Operand.Vector(vectorDestination + 3),
                     ],
+                    _ when IsDataShareAtomic(opcode) &&
+                        opcode.Contains("Rtn", StringComparison.Ordinal) => [
+                        Gen5Operand.Vector(vectorDestination),
+                    ],
                     _ => [],
                 };
                 break;
@@ -1953,8 +2022,8 @@ public static class Gen5ShaderTranslator
                     "BufferStoreDwordx2" => 2u,
                     "BufferStoreDwordx3" => 3u,
                     "BufferStoreDwordx4" => 4u,
-                    "BufferAtomicAdd" => 1u,
-                    "BufferAtomicUMax" => 1u,
+                    "BufferAtomicCmpswap" => 2u,
+                    _ when opcode.StartsWith("BufferAtomic", StringComparison.Ordinal) => 1u,
                     _ => 0u,
                 };
                 sources =

tests/SharpEmu.Libs.Tests/Agc/Gen5ShaderAtomicDecodeTests.cs

@@ -0,0 +1,134 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Buffers.Binary;
+using SharpEmu.HLE;
+using SharpEmu.ShaderCompiler;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Agc;
+
+// Decodes synthetic GFX10 atomic instructions and checks the opcode names and operand wiring
+// that the SPIR-V translator relies on. Word layouts follow the RDNA2 ISA manual:
+// MUBUF op=word0[24:18], MIMG op=word0[24:18], DS op=word0[25:18].
+public sealed class Gen5ShaderAtomicDecodeTests
+{
+    private const ulong ShaderAddress = 0x1_0000_0000;
+    private const uint EndPgm = 0xBF810000;
+
+    // Compute-stage register block: COMPUTE_USER_DATA_0 and COMPUTE_PGM_RSRC2,
+    // required since TryCreateState validates the USER_SGPR count.
+    internal const uint ComputeUserDataRegister = 0x240;
+    internal const uint ComputePgmRsrc2Register = 0x213;
+
+    [Fact]
+    public void BufferAtomicUmax_DecodesControlAndDestination()
+    {
+        // BUFFER_ATOMIC_UMAX v1, off, s[0:3], 128 offset:8 glc
+        var instruction = DecodeSingle(0xE0E04008, 0x80000100);
+
+        Assert.Equal("BufferAtomicUmax", instruction.Opcode);
+        var control = Assert.IsType<Gen5BufferMemoryControl>(instruction.Control);
+        Assert.Equal(1u, control.DwordCount);
+        Assert.Equal(1u, control.VectorData);
+        Assert.Equal(0u, control.ScalarResource);
+        Assert.Equal(8, control.OffsetBytes);
+        Assert.True(control.Glc);
+        Assert.Equal(new[] { Gen5Operand.Vector(1) }, instruction.Destinations);
+    }
+
+    [Fact]
+    public void BufferAtomicCmpswap_UsesTwoDataRegisters()
+    {
+        // BUFFER_ATOMIC_CMPSWAP v[1:2], off, s[0:3], 128 glc
+        var instruction = DecodeSingle(0xE0C44000, 0x80000100);
+
+        Assert.Equal("BufferAtomicCmpswap", instruction.Opcode);
+        var control = Assert.IsType<Gen5BufferMemoryControl>(instruction.Control);
+        Assert.Equal(2u, control.DwordCount);
+        Assert.Equal(1u, control.VectorData);
+    }
+
+    [Fact]
+    public void ImageAtomicAdd_KeepsDataRegisterAsDestination()
+    {
+        // IMAGE_ATOMIC_ADD v2, v[0:1], s[4:11] dmask:0x1 dim:2D glc
+        var instruction = DecodeSingle(0xF0442100, 0x00010200);
+
+        Assert.Equal("ImageAtomicAdd", instruction.Opcode);
+        var control = Assert.IsType<Gen5ImageControl>(instruction.Control);
+        Assert.Equal(2u, control.VectorData);
+        Assert.Equal(4u, control.ScalarResource);
+        Assert.True(control.Glc);
+        Assert.Equal(new[] { Gen5Operand.Vector(2) }, instruction.Destinations);
+    }
+
+    [Fact]
+    public void DsAddU32_HasAddressAndDataSourcesButNoDestination()
+    {
+        // DS_ADD_U32 v0, v1
+        var instruction = DecodeSingle(0xD8000000, 0x00000100);
+
+        Assert.Equal("DsAddU32", instruction.Opcode);
+        Assert.Equal(
+            new[] { Gen5Operand.Vector(0), Gen5Operand.Vector(1) },
+            instruction.Sources);
+        Assert.Empty(instruction.Destinations);
+    }
+
+    [Fact]
+    public void DsAddRtnU32_WritesReturnRegister()
+    {
+        // DS_ADD_RTN_U32 v3, v0, v1
+        var instruction = DecodeSingle(0xD8800000, 0x03000100);
+
+        Assert.Equal("DsAddRtnU32", instruction.Opcode);
+        Assert.Equal(
+            new[] { Gen5Operand.Vector(0), Gen5Operand.Vector(1) },
+            instruction.Sources);
+        Assert.Equal(new[] { Gen5Operand.Vector(3) }, instruction.Destinations);
+    }
+
+    [Fact]
+    public void DsCmpstRtnB32_OrdersComparatorBeforeNewValue()
+    {
+        // DS_CMPST_RTN_B32 v3, v0, v1, v2 - DATA0 (v1) is the comparator, DATA1 (v2) the
+        // new value, reversed relative to buffer/image cmpswap.
+        var instruction = DecodeSingle(0xD8C00000, 0x03020100);
+
+        Assert.Equal("DsCmpstRtnB32", instruction.Opcode);
+        Assert.Equal(
+            new[] { Gen5Operand.Vector(0), Gen5Operand.Vector(1), Gen5Operand.Vector(2) },
+            instruction.Sources);
+        Assert.Equal(new[] { Gen5Operand.Vector(3) }, instruction.Destinations);
+    }
+
+    private static Gen5ShaderInstruction DecodeSingle(params uint[] words)
+    {
+        var memory = new FakeCpuMemory(ShaderAddress, 0x1000);
+        var ctx = new CpuContext(memory, Generation.Gen5);
+        WriteProgram(memory, ShaderAddress, words);
+        Assert.True(
+            Gen5ShaderTranslator.TryCreateState(
+                ctx,
+                ShaderAddress,
+                0,
+                new Dictionary<uint, uint> { [ComputePgmRsrc2Register] = 0 },
+                ComputeUserDataRegister,
+                out var state,
+                out var error),
+            error);
+        return state.Program.Instructions[0];
+    }
+
+    internal static void WriteProgram(FakeCpuMemory memory, ulong address, uint[] words)
+    {
+        Span<byte> buffer = stackalloc byte[4];
+        foreach (var word in words.Append(EndPgm))
+        {
+            BinaryPrimitives.WriteUInt32LittleEndian(buffer, word);
+            Assert.True(memory.TryWrite(address, buffer));
+            address += sizeof(uint);
+        }
+    }
+}

tests/SharpEmu.Libs.Tests/Agc/Gen5SpirvAtomicTranslationTests.cs

@@ -0,0 +1,137 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Buffers.Binary;
+using SharpEmu.HLE;
+using SharpEmu.ShaderCompiler;
+using SharpEmu.ShaderCompiler.Vulkan;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Agc;
+
+// End-to-end pipeline tests: synthetic GFX10 program -> decode -> scalar evaluation -> SPIR-V.
+// Each test asserts the expected OpAtomic* instructions land in the emitted module.
+public sealed class Gen5SpirvAtomicTranslationTests
+{
+    private const ulong ShaderAddress = 0x1_0000_0000;
+    private const ulong BufferAddress = 0x1_0000_1000;
+
+    [Fact]
+    public void BufferAtomics_EmitAtomicOpcodes()
+    {
+        // BUFFER_ATOMIC_UMAX v1, BUFFER_ATOMIC_CMPSWAP v[1:2], BUFFER_ATOMIC_INC v1,
+        // all against the V# in s[0:3].
+        var opcodes = CompileCompute(
+            [
+                0xE0E04008, 0x80000100,
+                0xE0C44000, 0x80000100,
+                0xE0F00000, 0x80000100,
+            ],
+            BufferDescriptorRegisters());
+
+        Assert.Contains((ushort)SpirvOp.AtomicUMax, opcodes);
+        Assert.Contains((ushort)SpirvOp.AtomicCompareExchange, opcodes);
+        Assert.Contains((ushort)SpirvOp.AtomicIIncrement, opcodes);
+    }
+
+    [Fact]
+    public void DataShareAtomics_EmitAtomicOpcodes()
+    {
+        // DS_ADD_RTN_U32 v3, v0, v1; DS_CMPST_RTN_B32 v3, v0, v1, v2; DS_MAX_U32 v0, v1.
+        var opcodes = CompileCompute(
+            [
+                0xD8800000, 0x03000100,
+                0xD8C00000, 0x03020100,
+                0xD8200000, 0x00000100,
+            ],
+            new Dictionary<uint, uint>());
+
+        Assert.Contains((ushort)SpirvOp.AtomicIAdd, opcodes);
+        Assert.Contains((ushort)SpirvOp.AtomicCompareExchange, opcodes);
+        Assert.Contains((ushort)SpirvOp.AtomicUMax, opcodes);
+    }
+
+    [Fact]
+    public void ImageAtomicAdd_EmitsTexelPointerAndAtomicAdd()
+    {
+        // IMAGE_ATOMIC_ADD v2, v[0:1], s[4:11] dmask:0x1 dim:2D glc against an R32ui T#.
+        var opcodes = CompileCompute(
+            [0xF0442100, 0x00010200],
+            new Dictionary<uint, uint>
+            {
+                // Descriptor word1 dataFormat (bits 28:20) = 20 selects R32ui/Uint.
+                [5] = 20u << 20,
+            });
+
+        Assert.Contains((ushort)SpirvOp.ImageTexelPointer, opcodes);
+        Assert.Contains((ushort)SpirvOp.AtomicIAdd, opcodes);
+    }
+
+    private static Dictionary<uint, uint> BufferDescriptorRegisters() => new()
+    {
+        // V# in s[0:3]: base=BufferAddress, stride=0, numRecords=64 bytes, type=0.
+        [0] = unchecked((uint)BufferAddress),
+        [1] = (uint)(BufferAddress >> 32),
+        [2] = 64,
+        [3] = 0,
+    };
+
+    private static HashSet<ushort> CompileCompute(
+        uint[] programWords,
+        Dictionary<uint, uint> userDataSgprs)
+    {
+        var memory = new FakeCpuMemory(ShaderAddress, 0x2000);
+        var ctx = new CpuContext(memory, Generation.Gen5);
+        Gen5ShaderAtomicDecodeTests.WriteProgram(memory, ShaderAddress, programWords);
+        // COMPUTE_PGM_RSRC2 advertises 16 user SGPRs; the user data words at
+        // COMPUTE_USER_DATA_0 + index seed s[0..15] for the scalar evaluator.
+        var shaderRegisters = new Dictionary<uint, uint>
+        {
+            [Gen5ShaderAtomicDecodeTests.ComputePgmRsrc2Register] = 16u << 1,
+        };
+        foreach (var (sgpr, value) in userDataSgprs)
+        {
+            shaderRegisters[Gen5ShaderAtomicDecodeTests.ComputeUserDataRegister + sgpr] = value;
+        }
+
+        Assert.True(
+            Gen5ShaderTranslator.TryCreateState(
+                ctx,
+                ShaderAddress,
+                0,
+                shaderRegisters,
+                Gen5ShaderAtomicDecodeTests.ComputeUserDataRegister,
+                out var state,
+                out var error),
+            error);
+        Assert.True(
+            Gen5ShaderScalarEvaluator.TryEvaluate(ctx, state, out var evaluation, out error),
+            error);
+        Assert.True(
+            Gen5SpirvTranslator.TryCompileComputeShader(
+                state,
+                evaluation,
+                1,
+                1,
+                1,
+                out var shader,
+                out error),
+            error);
+        return CollectOpcodes(shader.Spirv);
+    }
+
+    private static HashSet<ushort> CollectOpcodes(byte[] spirv)
+    {
+        var opcodes = new HashSet<ushort>();
+        // 5-word SPIR-V header, then (wordCount << 16 | opcode) packed instructions.
+        for (var offset = 5 * sizeof(uint); offset + sizeof(uint) <= spirv.Length;)
+        {
+            var word = BinaryPrimitives.ReadUInt32LittleEndian(
+                spirv.AsSpan(offset, sizeof(uint)));
+            opcodes.Add((ushort)word);
+            offset += Math.Max((int)(word >> 16), 1) * sizeof(uint);
+        }
+
+        return opcodes;
+    }
+}

tests/SharpEmu.Libs.Tests/Ampr/AprStreamingContractTests.cs

@@ -0,0 +1,99 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.HLE;
+using SharpEmu.Libs.Ampr;
+using SharpEmu.Libs.Kernel;
+using System.Buffers.Binary;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Ampr;
+
+public sealed class AprStreamingContractTests
+{
+    [Fact]
+    public void ResolveStatAndReadFile_UsesSharedAprFileId()
+    {
+        const ulong memoryBase = 0x1_0000_0000;
+        const ulong pathListAddress = memoryBase + 0x100;
+        const ulong pathAddress = memoryBase + 0x200;
+        const ulong idsAddress = memoryBase + 0x800;
+        const ulong statAddress = memoryBase + 0x900;
+        const ulong commandBufferAddress = memoryBase + 0x1000;
+        const ulong recordBufferAddress = memoryBase + 0x1100;
+        const ulong destinationAddress = memoryBase + 0x2000;
+        const ulong stackAddress = memoryBase + 0x3000;
+        byte[] fileContents = [10, 11, 12, 13, 14, 15, 16, 17];
+        var hostPath = Path.GetTempFileName();
+
+        try
+        {
+            File.WriteAllBytes(hostPath, fileContents);
+            var memory = new FakeCpuMemory(memoryBase, 0x4000);
+            var context = new CpuContext(memory, Generation.Gen5);
+            memory.WriteCString(pathAddress, hostPath);
+            WriteUInt64(memory, pathListAddress, pathAddress);
+
+            context[CpuRegister.Rdi] = pathListAddress;
+            context[CpuRegister.Rsi] = 1;
+            context[CpuRegister.Rdx] = idsAddress;
+
+            Assert.Equal(0, KernelMemoryCompatExports.KernelAprResolveFilepathsToIds(context));
+
+            Span<byte> idBytes = stackalloc byte[sizeof(uint)];
+            Assert.True(memory.TryRead(idsAddress, idBytes));
+            var fileId = BinaryPrimitives.ReadUInt32LittleEndian(idBytes);
+            Assert.NotEqual(uint.MaxValue, fileId);
+
+            context[CpuRegister.Rdi] = fileId;
+            context[CpuRegister.Rsi] = statAddress;
+
+            Assert.Equal(0, KernelMemoryCompatExports.KernelAprGetFileStat(context));
+
+            Span<byte> stat = stackalloc byte[120];
+            Assert.True(memory.TryRead(statAddress, stat));
+            Assert.Equal(fileContents.Length, BinaryPrimitives.ReadInt64LittleEndian(stat[72..]));
+
+            context[CpuRegister.Rdi] = commandBufferAddress;
+            context[CpuRegister.Rsi] = recordBufferAddress;
+            context[CpuRegister.Rdx] = 0x100;
+
+            Assert.Equal(0, AmprExports.CommandBufferConstructor(context));
+
+            const ulong readOffset = 2;
+            const ulong readSize = 4;
+            WriteUInt64(memory, stackAddress + sizeof(ulong), readOffset);
+            context[CpuRegister.Rsp] = stackAddress;
+            context[CpuRegister.Rdi] = commandBufferAddress;
+            context[CpuRegister.Rcx] = fileId;
+            context[CpuRegister.R8] = destinationAddress;
+            context[CpuRegister.R9] = readSize;
+
+            Assert.Equal(0, AmprExports.AprCommandBufferReadFile(context));
+
+            Span<byte> destination = stackalloc byte[(int)readSize];
+            Assert.True(memory.TryRead(destinationAddress, destination));
+            Assert.Equal(fileContents.AsSpan((int)readOffset, (int)readSize), destination);
+
+            Span<byte> record = stackalloc byte[0x30];
+            Assert.True(memory.TryRead(recordBufferAddress, record));
+            Assert.Equal(1U, BinaryPrimitives.ReadUInt32LittleEndian(record));
+            Assert.Equal(fileId, BinaryPrimitives.ReadUInt32LittleEndian(record[0x04..]));
+            Assert.Equal(destinationAddress, BinaryPrimitives.ReadUInt64LittleEndian(record[0x08..]));
+            Assert.Equal(readSize, BinaryPrimitives.ReadUInt64LittleEndian(record[0x10..]));
+            Assert.Equal(readOffset, BinaryPrimitives.ReadUInt64LittleEndian(record[0x18..]));
+            Assert.Equal(readSize, BinaryPrimitives.ReadUInt64LittleEndian(record[0x20..]));
+        }
+        finally
+        {
+            File.Delete(hostPath);
+        }
+    }
+
+    private static void WriteUInt64(FakeCpuMemory memory, ulong address, ulong value)
+    {
+        Span<byte> bytes = stackalloc byte[sizeof(ulong)];
+        BinaryPrimitives.WriteUInt64LittleEndian(bytes, value);
+        Assert.True(memory.TryWrite(address, bytes));
+    }
+}

tests/SharpEmu.Libs.Tests/Cpu/BmiInstructionEmulatorTests.cs

@@ -0,0 +1,243 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Core.Cpu.Emulation;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Cpu;
+
+// These exercise the pure BMI1/BMI2/ABM semantics used by the illegal-instruction software
+// fallback. The expected values were computed by hand from the Intel/AMD definitions so a
+// regression in the bit math or the flag handling fails here without needing a live guest.
+public sealed class BmiInstructionEmulatorTests
+{
+    private const uint Carry = 1u << 0;
+    private const uint Zero = 1u << 6;
+    private const uint Sign = 1u << 7;
+    private const uint Overflow = 1u << 11;
+    private const uint DirectionFlag = 1u << 10; // Unrelated flag; must be preserved.
+
+    [Fact]
+    public void Andn_ClearsSourceBitsAndFlags()
+    {
+        uint flags = Overflow | Carry | DirectionFlag;
+        var result = BmiInstructionEmulator.Andn(0x0000_00F0, 0x0000_00FF, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0x0000_000FUL, result);
+        Assert.Equal(0u, flags & Carry);
+        Assert.Equal(0u, flags & Overflow);
+        Assert.Equal(0u, flags & Zero);
+        Assert.Equal(0u, flags & Sign);
+        Assert.Equal(DirectionFlag, flags & DirectionFlag);
+    }
+
+    [Fact]
+    public void Andn_SetsZeroFlagWhenResultIsZero()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Andn(0xFF, 0xFF, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0UL, result);
+        Assert.Equal(Zero, flags & Zero);
+    }
+
+    [Fact]
+    public void Andn_SetsSignFlagOnHighBit32()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Andn(0, 0x8000_0000, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0x8000_0000UL, result);
+        Assert.Equal(Sign, flags & Sign);
+    }
+
+    [Fact]
+    public void Andn_MasksTo64Bits()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Andn(0xFFFF_FFFF_FFFF_FF00, 0xFF, GprOperandSize.Bits64, ref flags);
+
+        Assert.Equal(0xFFUL, result);
+    }
+
+    [Theory]
+    [InlineData(0x0000_000CUL, 0x0000_0004UL, false)] // isolate lowest set bit
+    [InlineData(0x0000_0000UL, 0x0000_0000UL, true)]  // src == 0 -> CF clear, ZF set
+    public void Blsi_IsolatesLowestBit(ulong src, ulong expected, bool zero)
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Blsi(src, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(expected, result);
+        Assert.Equal(src != 0 ? Carry : 0u, flags & Carry);
+        Assert.Equal(zero ? Zero : 0u, flags & Zero);
+    }
+
+    [Fact]
+    public void Blsmsk_MasksThroughLowestBit()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Blsmsk(0x0000_000C, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0x0000_0007UL, result);
+        Assert.Equal(0u, flags & Carry);
+    }
+
+    [Fact]
+    public void Blsmsk_SetsCarryWhenSourceZero32()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Blsmsk(0, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0xFFFF_FFFFUL, result);
+        Assert.Equal(Carry, flags & Carry);
+        Assert.Equal(Sign, flags & Sign);
+    }
+
+    [Fact]
+    public void Blsr_ResetsLowestBit()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Blsr(0x0000_000C, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0x0000_0008UL, result);
+        Assert.Equal(0u, flags & Carry);
+    }
+
+    [Fact]
+    public void Blsr_SetsCarryAndZeroWhenSourceZero()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Blsr(0, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0UL, result);
+        Assert.Equal(Carry, flags & Carry);
+        Assert.Equal(Zero, flags & Zero);
+    }
+
+    [Fact]
+    public void Bextr_ExtractsBitField()
+    {
+        uint flags = 0;
+        // start = 4, len = 8 -> bits [11:4] of 0x12345678 == 0x67
+        var control = (8UL << 8) | 4UL;
+        var result = BmiInstructionEmulator.Bextr(0x1234_5678, control, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0x0000_0067UL, result);
+        Assert.Equal(0u, flags & Zero);
+        Assert.Equal(0u, flags & Carry);
+        Assert.Equal(0u, flags & Overflow);
+    }
+
+    [Fact]
+    public void Bextr_StartBeyondWidthYieldsZero()
+    {
+        uint flags = 0;
+        var control = (8UL << 8) | 40UL; // start = 40 >= 32
+        var result = BmiInstructionEmulator.Bextr(0xFFFF_FFFF, control, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0UL, result);
+        Assert.Equal(Zero, flags & Zero);
+    }
+
+    [Fact]
+    public void Bzhi_ZeroesHighBits()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Bzhi(0xFFFF_FFFF, 8, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0x0000_00FFUL, result);
+        Assert.Equal(0u, flags & Carry);
+    }
+
+    [Fact]
+    public void Bzhi_SetsCarryWhenIndexAtOrBeyondWidth()
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Bzhi(0xFFFF_FFFF, 32, GprOperandSize.Bits32, ref flags);
+
+        Assert.Equal(0xFFFF_FFFFUL, result);
+        Assert.Equal(Carry, flags & Carry);
+    }
+
+    [Theory]
+    [InlineData(0x0000_0008UL, GprOperandSize.Bits32, 3UL, false)]
+    [InlineData(0x0000_0001UL, GprOperandSize.Bits32, 0UL, false)]
+    [InlineData(0x0000_0000UL, GprOperandSize.Bits32, 32UL, true)]
+    [InlineData(0x1_0000_0000UL, GprOperandSize.Bits64, 32UL, false)]
+    public void Tzcnt_CountsTrailingZeros(ulong src, GprOperandSize size, ulong expected, bool carry)
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Tzcnt(src, size, ref flags);
+
+        Assert.Equal(expected, result);
+        Assert.Equal(carry ? Carry : 0u, flags & Carry);
+    }
+
+    [Theory]
+    [InlineData(0x0000_0001UL, GprOperandSize.Bits32, 31UL, false)]
+    [InlineData(0x8000_0000UL, GprOperandSize.Bits32, 0UL, false)]
+    [InlineData(0x0000_0000UL, GprOperandSize.Bits32, 32UL, true)]
+    [InlineData(0x0000_0001UL, GprOperandSize.Bits64, 63UL, false)]
+    [InlineData(0x0000_0000UL, GprOperandSize.Bits64, 64UL, true)]
+    public void Lzcnt_CountsLeadingZeros(ulong src, GprOperandSize size, ulong expected, bool carry)
+    {
+        uint flags = 0;
+        var result = BmiInstructionEmulator.Lzcnt(src, size, ref flags);
+
+        Assert.Equal(expected, result);
+        Assert.Equal(carry ? Carry : 0u, flags & Carry);
+    }
+
+    [Theory]
+    [InlineData(0x1234_5678UL, 8, GprOperandSize.Bits32, 0x7812_3456UL)]
+    [InlineData(0x1234_5678UL, 0, GprOperandSize.Bits32, 0x1234_5678UL)]
+    [InlineData(0x0123_4567_89AB_CDEFUL, 4, GprOperandSize.Bits64, 0xF012_3456_789A_BCDEUL)]
+    public void Rorx_RotatesRight(ulong src, int count, GprOperandSize size, ulong expected)
+    {
+        Assert.Equal(expected, BmiInstructionEmulator.Rorx(src, count, size));
+    }
+
+    [Theory]
+    [InlineData(0x8000_0000UL, 4, GprOperandSize.Bits32, 0xF800_0000UL)]
+    [InlineData(0x8000_0000UL, 36, GprOperandSize.Bits32, 0xF800_0000UL)] // count masked to 4
+    [InlineData(0x8000_0000_0000_0000UL, 4, GprOperandSize.Bits64, 0xF800_0000_0000_0000UL)]
+    public void Sarx_ArithmeticShiftRight(ulong src, int count, GprOperandSize size, ulong expected)
+    {
+        Assert.Equal(expected, BmiInstructionEmulator.Sarx(src, count, size));
+    }
+
+    [Theory]
+    [InlineData(0x0000_0001UL, 4, GprOperandSize.Bits32, 0x0000_0010UL)]
+    [InlineData(0x0000_0001UL, 33, GprOperandSize.Bits32, 0x0000_0002UL)] // count masked to 1
+    public void Shlx_LogicalShiftLeft(ulong src, int count, GprOperandSize size, ulong expected)
+    {
+        Assert.Equal(expected, BmiInstructionEmulator.Shlx(src, count, size));
+    }
+
+    [Theory]
+    [InlineData(0x8000_0000UL, 4, GprOperandSize.Bits32, 0x0800_0000UL)]
+    [InlineData(0x8000_0000_0000_0000UL, 4, GprOperandSize.Bits64, 0x0800_0000_0000_0000UL)]
+    public void Shrx_LogicalShiftRight(ulong src, int count, GprOperandSize size, ulong expected)
+    {
+        Assert.Equal(expected, BmiInstructionEmulator.Shrx(src, count, size));
+    }
+
+    [Fact]
+    public void PdepAndPext_AreInverseForContiguousSource()
+    {
+        var deposited = BmiInstructionEmulator.Pdep(0x0000_000F, 0x0000_00AA, GprOperandSize.Bits32);
+        Assert.Equal(0x0000_00AAUL, deposited);
+
+        var extracted = BmiInstructionEmulator.Pext(0x0000_00AA, 0x0000_00AA, GprOperandSize.Bits32);
+        Assert.Equal(0x0000_000FUL, extracted);
+    }
+
+    [Fact]
+    public void Pext_GathersSelectedBits()
+    {
+        // mask selects bit positions 1,3,5,7; source has 1s only at 5 and 7 -> packed 0b1100
+        var extracted = BmiInstructionEmulator.Pext(0xF0, 0xAA, GprOperandSize.Bits32);
+        Assert.Equal(0x0000_000CUL, extracted);
+    }
+}

tests/SharpEmu.Libs.Tests/Cpu/GuestContextTransferValidationTests.cs

@@ -0,0 +1,61 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Core.Cpu.Native;
+using SharpEmu.HLE;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Cpu;
+
+public sealed class GuestContextTransferValidationTests
+{
+    private const ulong MemoryBase = 0x1_0000_0000;
+
+    [Fact]
+    public void MappedGuestInstructionPointer_IsAccepted()
+    {
+        var memory = new FakeCpuMemory(MemoryBase, 0x1000);
+        var continuation = CreateContinuation(MemoryBase + 0x100, MemoryBase + 0x800);
+
+        Assert.True(DirectExecutionBackend.TryValidateGuestContextTransferTarget(
+            memory,
+            continuation,
+            out var error));
+        Assert.Null(error);
+    }
+
+    [Fact]
+    public void UnmappedGuestInstructionPointer_IsRejected()
+    {
+        var memory = new FakeCpuMemory(MemoryBase, 0x1000);
+        var continuation = CreateContinuation(MemoryBase + 0x2000, MemoryBase + 0x800);
+
+        Assert.False(DirectExecutionBackend.TryValidateGuestContextTransferTarget(
+            memory,
+            continuation,
+            out var error));
+        Assert.Contains("not mapped guest memory", error);
+    }
+
+    [Theory]
+    [InlineData(0UL, MemoryBase + 0x800)]
+    [InlineData(MemoryBase + 0x100, 0UL)]
+    public void InvalidInstructionOrStackPointer_IsRejected(ulong rip, ulong rsp)
+    {
+        var memory = new FakeCpuMemory(MemoryBase, 0x1000);
+        var continuation = CreateContinuation(rip, rsp);
+
+        Assert.False(DirectExecutionBackend.TryValidateGuestContextTransferTarget(
+            memory,
+            continuation,
+            out var error));
+        Assert.Contains("invalid guest context transfer target", error);
+    }
+
+    private static GuestCpuContinuation CreateContinuation(ulong rip, ulong rsp) =>
+        new()
+        {
+            Rip = rip,
+            Rsp = rsp,
+        };
+}

tests/SharpEmu.Libs.Tests/Cpu/ImportTrampolineAbiTests.cs

@@ -0,0 +1,96 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Core.Cpu.Native;
+using SharpEmu.HLE;
+using System.Buffers.Binary;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Cpu;
+
+public sealed class ImportTrampolineAbiTests
+{
+    [Fact]
+    public unsafe void GeneratedTrampoline_PreservesVolatileGuestState()
+    {
+        if (RuntimeInformation.ProcessArchitecture != Architecture.X64)
+        {
+            // The production backend emits and initializes x86-64 callback
+            // thunks, so inspect it only in an x64 test process. Apple Silicon
+            // runs this path through the same Rosetta environment as SharpEmu.
+            return;
+        }
+
+        var code = CreateTrampolineBytes();
+
+        AssertContains(code, [0x48, 0x81, 0xEC, 0xB0, 0x00, 0x00, 0x00]); // sub rsp,0xB0
+        AssertContains(code, [0x48, 0x89, 0x04, 0x24]);                   // mov [rsp],rax
+        AssertContains(code, [0x4C, 0x89, 0x54, 0x24, 0x08]);             // mov [rsp+8],r10
+        AssertContains(code, [0x4C, 0x89, 0x5C, 0x24, 0x10]);             // mov [rsp+16],r11
+        AssertContains(code, [0x0F, 0xAE, 0x5C, 0x24, 0x18]);             // stmxcsr [rsp+24]
+        AssertContains(code, [0xD9, 0x7C, 0x24, 0x1C]);                   // fnstcw [rsp+28]
+        AssertContains(code, [0x4C, 0x8D, 0xA4, 0x24, 0xB0, 0, 0, 0]);   // lea r12,[rsp+0xB0]
+
+        for (var xmm = 0; xmm < 8; xmm++)
+        {
+            Span<byte> save = new byte[9];
+            save[0] = 0xF3;
+            save[1] = 0x0F;
+            save[2] = 0x7F;
+            save[3] = (byte)(0x84 | (xmm << 3));
+            save[4] = 0x24;
+            BinaryPrimitives.WriteInt32LittleEndian(save[5..], 0x30 + (xmm * 0x10));
+            AssertContains(code, save);
+        }
+
+        for (var xmm = 0; xmm < 2; xmm++)
+        {
+            Span<byte> restore = new byte[10];
+            restore[0] = 0xF3;
+            restore[1] = 0x41;
+            restore[2] = 0x0F;
+            restore[3] = 0x6F;
+            restore[4] = (byte)(0x84 | (xmm << 3));
+            restore[5] = 0x24;
+            BinaryPrimitives.WriteInt32LittleEndian(restore[6..], -0x80 + (xmm * 0x10));
+            AssertContains(code, restore);
+        }
+    }
+
+    private static unsafe byte[] CreateTrampolineBytes()
+    {
+        var backend = (DirectExecutionBackend)RuntimeHelpers.GetUninitializedObject(
+            typeof(DirectExecutionBackend));
+        var trampolineList = typeof(DirectExecutionBackend).GetField(
+            "_importHandlerTrampolines",
+            BindingFlags.Instance | BindingFlags.NonPublic);
+        Assert.NotNull(trampolineList);
+        trampolineList.SetValue(backend, new List<nint>());
+
+        var createTrampoline = typeof(DirectExecutionBackend).GetMethod(
+            "CreateImportHandlerTrampoline",
+            BindingFlags.Instance | BindingFlags.NonPublic);
+        Assert.NotNull(createTrampoline);
+        var trampoline = (nint)createTrampoline.Invoke(backend, [0])!;
+        Assert.NotEqual(0, trampoline);
+
+        try
+        {
+            return new ReadOnlySpan<byte>((void*)trampoline, 512).ToArray();
+        }
+        finally
+        {
+            Assert.True(HostMemory.Free((void*)trampoline, 0, HostMemory.MEM_RELEASE));
+        }
+    }
+
+    private static void AssertContains(ReadOnlySpan<byte> code, ReadOnlySpan<byte> expected)
+    {
+        Assert.True(
+            code.IndexOf(expected) >= 0,
+            $"Generated trampoline did not contain {Convert.ToHexString(expected)}.");
+    }
+}

tests/SharpEmu.Libs.Tests/Kernel/KernelMemoryCompatExportsTests.cs

@@ -0,0 +1,66 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.HLE;
+using SharpEmu.Libs.Kernel;
+using System.Globalization;
+using System.Text;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Kernel;
+
+public sealed class KernelMemoryCompatExportsTests
+{
+    [Fact]
+    public void PosixStat_MissingFileReturnsMinusOne()
+    {
+        const ulong memoryBase = 0x1_0000_0000;
+        const ulong pathAddress = memoryBase + 0x100;
+        const ulong statAddress = memoryBase + 0x400;
+        var memory = new FakeCpuMemory(memoryBase, 0x1000);
+        var context = new CpuContext(memory, Generation.Gen5);
+        memory.WriteCString(pathAddress, "/__sharpemu_test_missing__/shader.cache");
+        context[CpuRegister.Rdi] = pathAddress;
+        context[CpuRegister.Rsi] = statAddress;
+
+        var result = KernelMemoryCompatExports.PosixStat(context);
+
+        Assert.Equal(-1, result);
+        Assert.Equal(ulong.MaxValue, context[CpuRegister.Rax]);
+    }
+
+    [Fact]
+    public void Sprintf_ReadsVariadicDoubleFromXmmRegister()
+    {
+        const ulong memoryBase = 0x1_0000_0000;
+        const ulong destinationAddress = memoryBase + 0x100;
+        const ulong formatAddress = memoryBase + 0x200;
+        var memory = new FakeCpuMemory(memoryBase, 0x1000);
+        var context = new CpuContext(memory, Generation.Gen5);
+        memory.WriteCString(formatAddress, "%.4f");
+        context[CpuRegister.Rdi] = destinationAddress;
+        context[CpuRegister.Rsi] = formatAddress;
+        context.SetXmmRegister(
+            0,
+            unchecked((ulong)BitConverter.DoubleToInt64Bits(0.5576)),
+            0);
+
+        var previousCulture = CultureInfo.CurrentCulture;
+        try
+        {
+            CultureInfo.CurrentCulture = CultureInfo.GetCultureInfo("es-ES");
+
+            var result = KernelMemoryCompatExports.Sprintf(context);
+
+            Assert.Equal(0, result);
+            Assert.Equal(6UL, context[CpuRegister.Rax]);
+            Span<byte> output = stackalloc byte[7];
+            Assert.True(memory.TryRead(destinationAddress, output));
+            Assert.Equal("0.5576\0", Encoding.UTF8.GetString(output));
+        }
+        finally
+        {
+            CultureInfo.CurrentCulture = previousCulture;
+        }
+    }
+}

tests/SharpEmu.Libs.Tests/Memory/GuestMemoryAllocatorTests.cs

@@ -95,6 +95,32 @@ public sealed class GuestMemoryAllocatorTests
         Assert.Equal(0UL, (ulong)memory.GetPointer(address));
     }
 
+    [Fact]
+    public void AlignedAllocationDoesNotRetainOverallocatedMappingsOutsideMacOS()
+    {
+        if (OperatingSystem.IsMacOS())
+        {
+            return;
+        }
+
+        const ulong desiredAddress = 0x00005000_0000_0123;
+        const ulong alignment = 0x10000;
+        const ulong alignedAddress = 0x00005000_0001_0000;
+        const ulong allocationSize = 0x2000;
+        using var host = new RelocatingHostMemory(alignedAddress);
+        using var memory = new PhysicalVirtualMemory(host);
+
+        Assert.True(memory.TryAllocateAtOrAbove(desiredAddress, 0x1234, false, alignment, out var actualAddress));
+        Assert.Equal(alignedAddress + alignment, actualAddress);
+        Assert.Equal(
+            [
+                (alignedAddress, allocationSize),
+                (alignedAddress + alignment, allocationSize),
+            ],
+            host.AllocationCalls);
+        Assert.Equal([alignedAddress + 0x1000], host.FreedAddresses);
+    }
+
     private sealed class FakeHostMemory : IHostMemory
     {
         public ulong Allocate(ulong desiredAddress, ulong size, HostPageProtection protection) =>
@@ -197,6 +223,63 @@ public sealed class GuestMemoryAllocatorTests
         }
     }
 
+    private sealed class RelocatingHostMemory(ulong firstAddress) : IHostMemory, IDisposable
+    {
+        private bool _relocatedFirstAllocation;
+
+        public List<(ulong Address, ulong Size)> AllocationCalls { get; } = [];
+
+        public List<ulong> FreedAddresses { get; } = [];
+
+        public ulong Allocate(ulong desiredAddress, ulong size, HostPageProtection protection)
+        {
+            AllocationCalls.Add((desiredAddress, size));
+            if (!_relocatedFirstAllocation)
+            {
+                _relocatedFirstAllocation = true;
+                return firstAddress + 0x1000;
+            }
+
+            return desiredAddress;
+        }
+
+        public ulong Reserve(ulong desiredAddress, ulong size, HostPageProtection protection) => 0;
+
+        public bool Commit(ulong address, ulong size, HostPageProtection protection) => true;
+
+        public bool Free(ulong address)
+        {
+            FreedAddresses.Add(address);
+            return true;
+        }
+
+        public bool Protect(ulong address, ulong size, HostPageProtection protection, out uint rawOldProtection)
+        {
+            rawOldProtection = 0;
+            return true;
+        }
+
+        public bool ProtectRaw(ulong address, ulong size, uint rawProtection, out uint rawOldProtection)
+        {
+            rawOldProtection = 0;
+            return true;
+        }
+
+        public bool Query(ulong address, out HostRegionInfo info)
+        {
+            info = default;
+            return false;
+        }
+
+        public void FlushInstructionCache(ulong address, ulong size)
+        {
+        }
+
+        public void Dispose()
+        {
+        }
+    }
+
     private sealed class LazyHostMemory(ulong address) : IHostMemory, IDisposable
     {
         public bool CommitSucceeds { get; set; } = true;

tests/SharpEmu.Libs.Tests/Memory/PosixHostMemoryTests.cs

@@ -0,0 +1,62 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Runtime.InteropServices;
+using SharpEmu.HLE.Host;
+using SharpEmu.HLE.Host.Posix;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Memory;
+
+public sealed unsafe class PosixHostMemoryTests
+{
+    private const int ProtRead = 0x1;
+    private const int ProtWrite = 0x2;
+    private const int MapPrivate = 0x02;
+    private const int MapAnonymousDarwin = 0x1000;
+    private static readonly nint MapFailed = -1;
+
+    [Fact]
+    public void ExactAllocationDoesNotReplaceUntrackedDarwinMapping()
+    {
+        if (!OperatingSystem.IsMacOS())
+        {
+            return;
+        }
+
+        var size = checked((nuint)Environment.SystemPageSize);
+        var externalMapping = mmap(
+            0,
+            size,
+            ProtRead | ProtWrite,
+            MapPrivate | MapAnonymousDarwin,
+            -1,
+            0);
+        Assert.NotEqual(MapFailed, externalMapping);
+
+        try
+        {
+            var sentinel = new Span<byte>((void*)externalMapping, checked((int)size));
+            sentinel.Fill(0xA5);
+
+            var hostMemory = new PosixHostMemory();
+            var result = hostMemory.Allocate(
+                (ulong)externalMapping,
+                (ulong)size,
+                HostPageProtection.ReadWrite);
+
+            Assert.Equal(0UL, result);
+            Assert.All(sentinel.ToArray(), value => Assert.Equal(0xA5, value));
+        }
+        finally
+        {
+            Assert.Equal(0, munmap(externalMapping, size));
+        }
+    }
+
+    [DllImport("libc", SetLastError = true)]
+    private static extern nint mmap(nint addr, nuint length, int prot, int flags, int fd, long offset);
+
+    [DllImport("libc", SetLastError = true)]
+    private static extern int munmap(nint addr, nuint length);
+}

tests/SharpEmu.Libs.Tests/Network/NetExportsTests.cs

@@ -0,0 +1,94 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.HLE;
+using SharpEmu.Libs.Network;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Network;
+
+// The libSceNet byte-order helpers take their operand in Rdi and return the converted value in
+// Rax. They swap endianness unconditionally, which is correct on the little-endian hosts (and
+// little-endian guest) the emulator targets, so network (big-endian) order is always a byte swap.
+public sealed class NetExportsTests
+{
+    private readonly CpuContext _ctx = new(new FakeCpuMemory(0x1_0000_0000, 0x1000), Generation.Gen5);
+
+    [Fact]
+    public void Htonl_SwapsAllFourBytes()
+    {
+        _ctx[CpuRegister.Rdi] = 0x01020304;
+
+        Assert.Equal(0, NetExports.NetHtonl(_ctx));
+        Assert.Equal(0x04030201UL, _ctx[CpuRegister.Rax]);
+    }
+
+    [Fact]
+    public void Ntohl_SwapsAllFourBytes()
+    {
+        _ctx[CpuRegister.Rdi] = 0x01020304;
+
+        Assert.Equal(0, NetExports.NetNtohl(_ctx));
+        Assert.Equal(0x04030201UL, _ctx[CpuRegister.Rax]);
+    }
+
+    [Fact]
+    public void Htons_SwapsLowTwoBytesOnly()
+    {
+        // High bits above the 16-bit short must be ignored, not folded into the result.
+        _ctx[CpuRegister.Rdi] = 0xFFFF_0102;
+
+        Assert.Equal(0, NetExports.NetHtons(_ctx));
+        Assert.Equal(0x0201UL, _ctx[CpuRegister.Rax]);
+    }
+
+    [Fact]
+    public void Ntohs_SwapsLowTwoBytesOnly()
+    {
+        _ctx[CpuRegister.Rdi] = 0xFFFF_0102;
+
+        Assert.Equal(0, NetExports.NetNtohs(_ctx));
+        Assert.Equal(0x0201UL, _ctx[CpuRegister.Rax]);
+    }
+
+    [Fact]
+    public void Htonl_IgnoresBitsAboveThe32BitWord()
+    {
+        _ctx[CpuRegister.Rdi] = 0xDEADBEEF_01020304;
+
+        Assert.Equal(0, NetExports.NetHtonl(_ctx));
+        Assert.Equal(0x04030201UL, _ctx[CpuRegister.Rax]);
+    }
+
+    [Theory]
+    [InlineData(0xDEADBEEFUL)]
+    [InlineData(0x00000000UL)]
+    [InlineData(0xFFFFFFFFUL)]
+    [InlineData(0x00000001UL)]
+    public void HtonlThenNtohl_RoundTripsToOriginal(ulong value)
+    {
+        _ctx[CpuRegister.Rdi] = value;
+        NetExports.NetHtonl(_ctx);
+
+        _ctx[CpuRegister.Rdi] = _ctx[CpuRegister.Rax];
+        NetExports.NetNtohl(_ctx);
+
+        Assert.Equal(value, _ctx[CpuRegister.Rax]);
+    }
+
+    // Regression guard: a non-palindromic value must not come back as 0. The functions previously
+    // computed the swap into Rax and then called SetReturn(0), which overwrote Rax, so every
+    // sceNetHtonl/Htons/Ntohl/Ntohs call returned 0 regardless of input.
+    [Fact]
+    public void ByteOrderConversions_DoNotReturnZeroForNonZeroInput()
+    {
+        _ctx[CpuRegister.Rdi] = 0x01020304;
+        NetExports.NetHtonl(_ctx);
+        Assert.NotEqual(0UL, _ctx[CpuRegister.Rax]);
+
+        _ctx[CpuRegister.Rax] = 0;
+        _ctx[CpuRegister.Rdi] = 0x0102;
+        NetExports.NetHtons(_ctx);
+        Assert.NotEqual(0UL, _ctx[CpuRegister.Rax]);
+    }
+}

tests/SharpEmu.Libs.Tests/Pad/HostWindowInputTests.cs

@@ -0,0 +1,19 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Libs.Pad;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Pad;
+
+public sealed class HostWindowInputTests
+{
+    [Theory]
+    [InlineData(-1.0f, 0)]
+    [InlineData(0.0f, 128)]
+    [InlineData(1.0f, 255)]
+    public void ToStickByteMapsFullSilkRange(float value, int expected)
+    {
+        Assert.Equal((byte)expected, HostWindowInput.ToStickByte(value));
+    }
+}

tests/SharpEmu.Libs.Tests/PlayGo/PlayGoExportsTests.cs

@@ -0,0 +1,209 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Buffers.Binary;
+using SharpEmu.HLE;
+using SharpEmu.Libs.PlayGo;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.PlayGo;
+
+[CollectionDefinition("PlayGoState", DisableParallelization = true)]
+public sealed class PlayGoStateCollection
+{
+    public const string Name = "PlayGoState";
+}
+
+[Collection(PlayGoStateCollection.Name)]
+public sealed class PlayGoExportsTests : IDisposable
+{
+    private const int BadChunkId = unchecked((int)0x80B2000C);
+    private const byte LocusNotDownloaded = 0;
+    private const byte LocusLocalFast = 3;
+    private const ulong MemoryBase = 0x1_0000_0000;
+    private const ulong InitParamsAddress = MemoryBase + 0x100;
+    private const ulong InitBufferAddress = MemoryBase + 0x1000;
+    private const ulong HandleAddress = MemoryBase + 0x200;
+    private const ulong ChunkIdsAddress = MemoryBase + 0x300;
+    private const ulong LociAddress = MemoryBase + 0x400;
+
+    private readonly string? _originalApp0Root;
+    private readonly string _app0Root;
+    private readonly FakeCpuMemory _memory = new(MemoryBase, 0x10000);
+    private readonly CpuContext _ctx;
+
+    public PlayGoExportsTests()
+    {
+        _originalApp0Root = Environment.GetEnvironmentVariable("SHARPEMU_APP0_DIR");
+        _app0Root = Path.Combine(Path.GetTempPath(), $"sharpemu-playgo-{Guid.NewGuid():N}");
+        Directory.CreateDirectory(_app0Root);
+        Environment.SetEnvironmentVariable("SHARPEMU_APP0_DIR", _app0Root);
+        PlayGoExports.ResetForTests();
+        _ctx = new CpuContext(_memory, Generation.Gen5);
+    }
+
+    [Fact]
+    public void GetLocus_MetadataFreeApp0_RejectsPastAuthoritativeDefaultChunk()
+    {
+        var handle = InitializeAndOpen();
+
+        Assert.Equal((int)OrbisGen2Result.ORBIS_GEN2_OK, GetLocus(handle, [0], 0x7F));
+        Assert.Equal(new byte[] { LocusLocalFast }, ReadLoci(1));
+
+        Assert.Equal(BadChunkId, GetLocus(handle, [1]));
+        Assert.Equal(new byte[] { LocusNotDownloaded }, ReadLoci(1));
+    }
+
+    [Fact]
+    public void GetLocus_ParsedChunkDefinitions_WritesPrefixAndRejectsFirstUnknownChunk()
+    {
+        File.WriteAllText(
+            Path.Combine(_app0Root, "playgo-chunkdefs.xml"),
+            "<playgo default_chunk=\"2\"><chunk id=\"2\"/><chunk id=\"7\"/></playgo>");
+        var handle = InitializeAndOpen();
+
+        Assert.Equal(BadChunkId, GetLocus(handle, [2, 3], 0xCC));
+        Assert.Equal(new byte[] { LocusLocalFast, LocusNotDownloaded }, ReadLoci(2));
+    }
+
+    [Theory]
+    [InlineData(UnusableMetadataKind.DatOnly)]
+    [InlineData(UnusableMetadataKind.MalformedChunkDefinitions)]
+    [InlineData(UnusableMetadataKind.UnrecognizedChunkDefinitions)]
+    public void GetLocus_UnparseableMetadata_RemainsPermissive(UnusableMetadataKind metadataKind)
+    {
+        switch (metadataKind)
+        {
+            case UnusableMetadataKind.DatOnly:
+                var sceSys = Directory.CreateDirectory(Path.Combine(_app0Root, "sce_sys"));
+                File.WriteAllBytes(Path.Combine(sceSys.FullName, "playgo-chunk.dat"), [0x70, 0x6C, 0x67, 0x6F]);
+                break;
+            case UnusableMetadataKind.MalformedChunkDefinitions:
+                File.WriteAllText(
+                    Path.Combine(_app0Root, "playgo-chunkdefs.xml"),
+                    "<playgo><chunk id=\"2\"></playgo>");
+                break;
+            case UnusableMetadataKind.UnrecognizedChunkDefinitions:
+                File.WriteAllText(Path.Combine(_app0Root, "playgo-chunkdefs.xml"), "<not-playgo/>");
+                break;
+            default:
+                throw new ArgumentOutOfRangeException(nameof(metadataKind), metadataKind, null);
+        }
+
+        var handle = InitializeAndOpen();
+
+        Assert.Equal((int)OrbisGen2Result.ORBIS_GEN2_OK, GetLocus(handle, [42]));
+        Assert.Equal(new byte[] { LocusLocalFast }, ReadLoci(1));
+    }
+
+    [Fact]
+    public void GetLocus_FaultingChunkAndOutputPointers_ReturnMemoryFault()
+    {
+        var handle = InitializeAndOpen();
+        const ulong faultingAddress = 0xDEAD_0000_0000;
+        Assert.True(_memory.TryWrite(LociAddress, new byte[] { 0xA5 }));
+
+        SetGetLocusArguments(handle, faultingAddress, 1, LociAddress);
+        Assert.Equal(
+            (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT,
+            PlayGoExports.PlayGoGetLocus(_ctx));
+        Assert.Equal(new byte[] { 0xA5 }, ReadLoci(1));
+
+        WriteChunkIds([1]);
+        SetGetLocusArguments(handle, ChunkIdsAddress, 1, faultingAddress);
+        Assert.Equal(
+            (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT,
+            PlayGoExports.PlayGoGetLocus(_ctx));
+    }
+
+    [Fact]
+    public void GetLocus_AllEntriesSentinel_DoesNotReadChunksOrWriteLoci()
+    {
+        var handle = InitializeAndOpen();
+        Assert.True(_memory.TryWrite(LociAddress, [0xA5]));
+
+        SetGetLocusArguments(handle, 0xDEAD_0000_0000, uint.MaxValue, LociAddress);
+
+        Assert.Equal(
+            (int)OrbisGen2Result.ORBIS_GEN2_OK,
+            PlayGoExports.PlayGoGetLocus(_ctx));
+        Assert.Equal(new byte[] { 0xA5 }, ReadLoci(1));
+    }
+
+    public void Dispose()
+    {
+        PlayGoExports.ResetForTests();
+        Environment.SetEnvironmentVariable("SHARPEMU_APP0_DIR", _originalApp0Root);
+        Directory.Delete(_app0Root, recursive: true);
+    }
+
+    private uint InitializeAndOpen()
+    {
+        Span<byte> initParams = stackalloc byte[16];
+        BinaryPrimitives.WriteUInt64LittleEndian(initParams, InitBufferAddress);
+        BinaryPrimitives.WriteUInt32LittleEndian(initParams[8..], 0x200000);
+        Assert.True(_memory.TryWrite(InitParamsAddress, initParams));
+
+        _ctx[CpuRegister.Rdi] = InitParamsAddress;
+        Assert.Equal(
+            (int)OrbisGen2Result.ORBIS_GEN2_OK,
+            PlayGoExports.PlayGoInitialize(_ctx));
+
+        _ctx[CpuRegister.Rdi] = HandleAddress;
+        _ctx[CpuRegister.Rsi] = 0;
+        Assert.Equal(
+            (int)OrbisGen2Result.ORBIS_GEN2_OK,
+            PlayGoExports.PlayGoOpen(_ctx));
+
+        Span<byte> handleBytes = stackalloc byte[sizeof(uint)];
+        Assert.True(_memory.TryRead(HandleAddress, handleBytes));
+        return BinaryPrimitives.ReadUInt32LittleEndian(handleBytes);
+    }
+
+    private int GetLocus(uint handle, ushort[] chunkIds, byte? fill = null)
+    {
+        WriteChunkIds(chunkIds);
+        if (fill is { } fillValue)
+        {
+            var initialLoci = new byte[chunkIds.Length];
+            Array.Fill(initialLoci, fillValue);
+            Assert.True(_memory.TryWrite(LociAddress, initialLoci));
+        }
+
+        SetGetLocusArguments(handle, ChunkIdsAddress, (uint)chunkIds.Length, LociAddress);
+        return PlayGoExports.PlayGoGetLocus(_ctx);
+    }
+
+    private void WriteChunkIds(ushort[] chunkIds)
+    {
+        var bytes = new byte[chunkIds.Length * sizeof(ushort)];
+        for (var i = 0; i < chunkIds.Length; i++)
+        {
+            BinaryPrimitives.WriteUInt16LittleEndian(bytes.AsSpan(i * sizeof(ushort)), chunkIds[i]);
+        }
+
+        Assert.True(_memory.TryWrite(ChunkIdsAddress, bytes));
+    }
+
+    private byte[] ReadLoci(int count)
+    {
+        var loci = new byte[count];
+        Assert.True(_memory.TryRead(LociAddress, loci));
+        return loci;
+    }
+
+    private void SetGetLocusArguments(uint handle, ulong chunkIds, uint count, ulong outLoci)
+    {
+        _ctx[CpuRegister.Rdi] = handle;
+        _ctx[CpuRegister.Rsi] = chunkIds;
+        _ctx[CpuRegister.Rdx] = count;
+        _ctx[CpuRegister.Rcx] = outLoci;
+    }
+
+    public enum UnusableMetadataKind
+    {
+        DatOnly,
+        MalformedChunkDefinitions,
+        UnrecognizedChunkDefinitions,
+    }
+}

tests/SharpEmu.Libs.Tests/VideoOut/VulkanHostBufferPoolTests.cs

@@ -0,0 +1,60 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Libs.VideoOut;
+using Silk.NET.Vulkan;
+using VkBuffer = Silk.NET.Vulkan.Buffer;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.VideoOut;
+
+public sealed class VulkanHostBufferPoolTests
+{
+    [Fact]
+    public void ReturnedAllocationCanBeRentedAgain()
+    {
+        var destroyed = new List<VulkanHostBufferAllocation>();
+        using var pool = new VulkanHostBufferPool(1024, destroyed.Add);
+        var key = new VulkanHostBufferPoolKey(BufferUsageFlags.StorageBufferBit, 256);
+        var allocation = Allocation(1, 2, key);
+
+        pool.Register(allocation);
+        Assert.True(pool.Return(allocation.Buffer, allocation.Memory));
+        Assert.Equal(256UL, pool.CachedBytes);
+
+        Assert.True(pool.TryRent(key, out var rented));
+        Assert.Equal(allocation, rented);
+        Assert.Equal(0UL, pool.CachedBytes);
+        Assert.Empty(destroyed);
+    }
+
+    [Fact]
+    public void ReturnDestroysAllocationThatWouldExceedBudget()
+    {
+        var destroyed = new List<VulkanHostBufferAllocation>();
+        using var pool = new VulkanHostBufferPool(256, destroyed.Add);
+        var key = new VulkanHostBufferPoolKey(BufferUsageFlags.VertexBufferBit, 512);
+        var allocation = Allocation(3, 4, key);
+
+        pool.Register(allocation);
+
+        Assert.True(pool.Return(allocation.Buffer, allocation.Memory));
+        Assert.Equal(0UL, pool.CachedBytes);
+        Assert.Equal([allocation], destroyed);
+        Assert.False(pool.TryRent(key, out _));
+    }
+
+    [Fact]
+    public void UnknownAllocationIsNotClaimedByPool()
+    {
+        using var pool = new VulkanHostBufferPool(1024, _ => { });
+
+        Assert.False(pool.Return(new VkBuffer(9), new DeviceMemory(10)));
+    }
+
+    private static VulkanHostBufferAllocation Allocation(
+        ulong buffer,
+        ulong memory,
+        VulkanHostBufferPoolKey key) =>
+        new(new VkBuffer(buffer), new DeviceMemory(memory), key, 0);
+}