[Diagnostics] Summarize synchronized table reads and trace several writer addresses

SHARPEMU_TRACE_GPU_READS=1 now also reports, every five seconds, the guest
words resource planning read through a GPU synchronization: read count, how
often the value changed, and the first and last value. SHARPEMU_TRACE_WRITER_ADDRESS
accepts a comma-separated list.

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

@@ -9,10 +9,23 @@ public sealed partial class DirectExecutionBackend
 {
     private const int HostStackStateBytes = 3 * sizeof(ulong);
 
-    private static unsafe bool TryGetGuestStackBounds(ulong stackPointer, out ulong bottom, out ulong top)
+    internal static unsafe bool TryGetGuestStackBounds(ulong stackPointer, out ulong bottom, out ulong top)
     {
+        if (OperatingSystem.IsWindows() &&
+            QueryVirtualMemoryInformation(-1, (void*)stackPointer, 0, out var allocation,
+                (nuint)sizeof(StackMemoryRegionInformation), null) != 0 &&
+            ((allocation.Flags & 1) == 0 || allocation.CommitSize == allocation.RegionSize) &&
+            allocation.RegionSize != 0 && allocation.RegionSize <= ulong.MaxValue - allocation.AllocationBase &&
+            stackPointer >= allocation.AllocationBase && stackPointer - allocation.AllocationBase < allocation.RegionSize)
+        {
+            bottom = allocation.AllocationBase;
+            top = bottom + allocation.RegionSize;
+            return true;
+        }
+
         bottom = top = 0;
-        if (VirtualQuery((void*)stackPointer, out var region, (nuint)sizeof(MEMORY_BASIC_INFORMATION64)) == 0 ||
+        var queried = VirtualQuery((void*)stackPointer, out var region, (nuint)sizeof(MEMORY_BASIC_INFORMATION64));
+        if (queried == 0 ||
             region.State != 0x1000 || region.RegionSize == 0 || region.RegionSize > ulong.MaxValue - region.BaseAddress)
         {
             return false;
@@ -176,4 +189,18 @@ public sealed partial class DirectExecutionBackend
 
     [DllImport("kernel32.dll", ExactSpelling = true)]
     private static extern void GetCurrentThreadStackLimits(out ulong lowLimit, out ulong highLimit);
+
+    [StructLayout(LayoutKind.Sequential)]
+    private struct StackMemoryRegionInformation
+    {
+        public ulong AllocationBase;
+        public uint AllocationProtect;
+        public uint Flags;
+        public ulong RegionSize;
+        public ulong CommitSize;
+    }
+
+    [DllImport("api-ms-win-core-memory-l1-1-4.dll", ExactSpelling = true)]
+    private static extern unsafe int QueryVirtualMemoryInformation(nint process, void* address, int informationClass,
+        out StackMemoryRegionInformation information, nuint informationSize, nuint* returnSize);
 }

src/SharpEmu.HLE/GpuMemory/GuestGpuMemory.cs

@@ -30,6 +30,9 @@ public sealed class GuestGpuMemory : IDisposable
     private readonly PageGuard _pages;
     private readonly ReaderWriterLockSlim _spansLock = new();
     private readonly SpanSet _spans = new();
+    private long _spanVersion;
+
+    public long SpanVersion => Interlocked.Read(ref _spanVersion);
     private sealed record GpuAttachment(IGpuQueueRelay? Gpu, IGpuTickScheduler? Scheduler);
 
     private readonly object _attachGate = new();
@@ -204,6 +207,7 @@ public sealed class GuestGpuMemory : IDisposable
         try
         {
             _spans.Add(address, size);
+            Interlocked.Increment(ref _spanVersion);
         }
         finally
         {
@@ -276,6 +280,7 @@ public sealed class GuestGpuMemory : IDisposable
                 try
                 {
                     _spans.Remove(address, size);
+                    Interlocked.Increment(ref _spanVersion);
                 }
                 finally
                 {

src/SharpEmu.Libs/Audio/AjmExports.cs

@@ -590,7 +590,16 @@ public static class AjmExports
             return ctx.SetReturn(OrbisAjmErrorJobCreation);
         }
 
-        var status = TryGetInstance(instanceId, out _) ? 0 : Atrac9DecodeState.ResultInvalidParameter;
+        var status = TryGetInstance(instanceId, out var instance) ? 0 : Atrac9DecodeState.ResultInvalidParameter;
+        Span<byte> gapless = stackalloc byte[AjmSidebandGaplessDecodeBytes];
+        if (status == 0 && gaplessAddress != 0 && ctx.Memory.TryRead(gaplessAddress, gapless))
+        {
+            instance!.Atrac9?.SetGapless(
+                BinaryPrimitives.ReadUInt32LittleEndian(gapless),
+                BinaryPrimitives.ReadUInt16LittleEndian(gapless[4..]),
+                reset != 0);
+        }
+
         WriteBasicResult(ctx, resultAddress, status);
         Trace(
             $"batch_job_set_gapless_decode instance=0x{instanceId:X8} " +
@@ -1163,6 +1172,10 @@ public static class AjmExports
 
         if ((flags & AjmJobSidebandFlagGaplessDecode) != 0 && (ulong)(offset + AjmSidebandGaplessDecodeBytes) <= size)
         {
+            var gapless = instance?.Atrac9?.Gapless ?? default;
+            BinaryPrimitives.WriteUInt32LittleEndian(sideband[offset..], gapless.TotalSamples);
+            BinaryPrimitives.WriteUInt16LittleEndian(sideband[(offset + 4)..], gapless.SkipSamples);
+            BinaryPrimitives.WriteUInt16LittleEndian(sideband[(offset + 6)..], gapless.SkippedSamples);
             offset += AjmSidebandGaplessDecodeBytes;
         }
 

src/SharpEmu.Libs/Audio/Atrac9DecodeState.cs

@@ -20,6 +20,8 @@ internal readonly record struct Atrac9DecodeResult(
     ulong TotalDecodedSamples,
     uint Frames);
 
+internal readonly record struct Atrac9Gapless(uint TotalSamples, ushort SkipSamples, ushort SkippedSamples);
+
 internal sealed class Atrac9DecodeState
 {
     internal const int ResultNotInitialized = 0x00000001;
@@ -47,6 +49,33 @@ internal sealed class Atrac9DecodeState
     private int _containerHeaderLength;
     private int _compressedLength;
     private ulong _totalDecodedSamples;
+    private Atrac9Gapless _gaplessInit;
+    private Atrac9Gapless _gapless;
+
+    public Atrac9Gapless Gapless
+    {
+        get
+        {
+            lock (_gate)
+            {
+                return _gapless;
+            }
+        }
+    }
+
+    public void SetGapless(uint totalSamples, ushort skipSamples, bool reset)
+    {
+        lock (_gate)
+        {
+            _gaplessInit = new Atrac9Gapless(totalSamples, skipSamples, 0);
+            if (reset || _gapless == default)
+            {
+                _gapless = _gaplessInit;
+            }
+        }
+    }
+
+    private bool HasSampleLimit => _gaplessInit.TotalSamples is not 0 and not uint.MaxValue;
 
     public Atrac9Config? Config
     {
@@ -82,6 +111,7 @@ internal sealed class Atrac9DecodeState
                 _compressedLength = 0;
                 _totalDecodedSamples = 0;
                 _containerHeaderLength = 0;
+                _gapless = _gaplessInit;
                 Trace(
                     $"initialized config={Convert.ToHexString(normalizedConfig)} channels={config.ChannelCount} " +
                     $"rate={config.SampleRate} frame_samples={config.FrameSamples} " +
@@ -114,6 +144,7 @@ internal sealed class Atrac9DecodeState
             _compressedLength = 0;
             _totalDecodedSamples = 0;
             _containerHeaderLength = 0;
+            _gapless = _gaplessInit;
             if (_compressed is not null)
             {
                 Array.Clear(_compressed);
@@ -153,7 +184,6 @@ internal sealed class Atrac9DecodeState
             }
 
             var bytesPerSample = GetBytesPerSample(encoding);
-            var outputBytesPerSuperframe = checked(config.SuperframeSamples * channels * bytesPerSample);
             var consumed = 0;
             var written = 0;
             uint frames = 0;
@@ -162,6 +192,11 @@ internal sealed class Atrac9DecodeState
             while (_compressedLength == config.SuperframeBytes ||
                    consumed < input.Length)
             {
+                if (HasSampleLimit && _gapless.TotalSamples == 0)
+                {
+                    break;
+                }
+
                 // Titles that stream whole .at9 files hand AJM the RIFF/WAVE
                 // container rather than a pointer into its `data` chunk, so the
                 // stream has to be advanced past the header before the first
@@ -202,7 +237,15 @@ internal sealed class Atrac9DecodeState
                     break;
                 }
 
-                if (output.Length - written < outputBytesPerSuperframe)
+                var skip = Math.Min(config.SuperframeSamples, (int)_gapless.SkipSamples);
+                var samples = config.SuperframeSamples - skip;
+                if (HasSampleLimit)
+                {
+                    samples = (int)Math.Min((uint)samples, _gapless.TotalSamples);
+                }
+
+                var outputBytes = checked(samples * channels * bytesPerSample);
+                if (output.Length - written < outputBytes)
                 {
                     status |= ResultNotEnoughRoom;
                     break;
@@ -231,14 +274,19 @@ internal sealed class Atrac9DecodeState
 
                 WriteInterleaved(
                     _planarPcm,
-                    output.Slice(written, outputBytesPerSuperframe),
+                    output.Slice(written, outputBytes),
-                    config.SuperframeSamples,
+                    skip,
+                    samples,
                     channels,
                     encoding);
 
-                written += outputBytesPerSuperframe;
+                _gapless = new Atrac9Gapless(
+                    HasSampleLimit ? _gapless.TotalSamples - (uint)samples : _gapless.TotalSamples,
+                    (ushort)(_gapless.SkipSamples - skip),
+                    (ushort)Math.Min(ushort.MaxValue, _gapless.SkippedSamples + config.SuperframeSamples - samples));
+                written += outputBytes;
                 _compressedLength = 0;
-                _totalDecodedSamples += unchecked((uint)config.SuperframeSamples);
+                _totalDecodedSamples += unchecked((uint)samples);
                 frames += unchecked((uint)config.FramesPerSuperframe);
 
                 if (!multipleFrames)
@@ -353,12 +401,13 @@ internal sealed class Atrac9DecodeState
     private static void WriteInterleaved(
         short[][] source,
         Span<byte> destination,
+        int firstSample,
         int samples,
         int channels,
         Atrac9PcmEncoding encoding)
     {
         var offset = 0;
-        for (var sample = 0; sample < samples; sample++)
+        for (var sample = firstSample; sample < firstSample + samples; sample++)
         {
             for (var channel = 0; channel < channels; channel++)
             {

src/SharpEmu.Libs/Audio/AudioOut2Exports.cs

@@ -60,6 +60,14 @@ public static class AudioOut2Exports
     // SceAudioOut2Attribute: u32 attributeId, 4 pad, const void* value, size_t valueSize.
     private const int AttributeEntrySize = 0x18;
     private const uint PortAttributeIdPcm = 0;
+    private const uint PortAttributeIdGain = 1;
+    private const uint PortAttributeIdPassthrough = 5;
+    private const uint PortAttributeIdAmbisonics = 8;
+    internal const uint AmbisonicsNone = uint.MaxValue;
+    internal const uint AmbisonicsAcnBase = 64;
+    internal const uint PassthroughLeft = 1;
+    internal const uint PassthroughRight = 2;
+    private const float HalfPower = 0.70710677f;
     private const ushort PortStateOutputConnectedPrimary = 0x01;
 
     // A host device that already holds this much audio is pacing the context; anything beyond the
@@ -131,6 +139,9 @@ public static class AudioOut2Exports
             return ahead <= 0 ? 0 : (uint)Math.Min((ahead + GrainTicks - 1) / GrainTicks, QueueDepth);
         }
 
+        public double DeviceSlotFreeMilliseconds =>
+            DeviceSlotFreeThreshold(GrainSamples, Frequency, QueueDepth);
+
         // Grains the device holds beyond the cushion, at most QueueDepth.
         public uint DeviceQueuedGrains(int queuedMilliseconds)
         {
@@ -197,6 +208,9 @@ public static class AudioOut2Exports
         public uint SamplingFrequency { get; }
         public uint GrainSamples { get; }
         public ulong PcmAddress;
+        public float Gain = 1f;
+        public uint Ambisonics = AmbisonicsNone;
+        public uint Passthrough;
 
         public int PcmPending;
 
@@ -419,6 +433,14 @@ public static class AudioOut2Exports
         {
             context.DevicePaced = true;
         }
+
+        if (submitted || advancedGrain == 1)
+        {
+            if (blocking != 0)
+            {
+                WaitForDeviceSlot(context);
+            }
+        }
         else
         {
             // Push is the blocking point of a grain: it waits for the grain an Advance claimed, or
@@ -545,6 +567,7 @@ public static class AudioOut2Exports
 
         Span<byte> entry = stackalloc byte[AttributeEntrySize];
         Span<byte> pcm = stackalloc byte[8];
+        Span<byte> word = stackalloc byte[sizeof(uint)];
         for (uint i = 0; i < attributeCount; i++)
         {
             if (!ctx.Memory.TryRead(attributesAddress + (i * AttributeEntrySize), entry))
@@ -555,7 +578,41 @@ public static class AudioOut2Exports
             var attributeId = BinaryPrimitives.ReadUInt32LittleEndian(entry);
             var valueAddress = BinaryPrimitives.ReadUInt64LittleEndian(entry[0x08..]);
             var valueSize = BinaryPrimitives.ReadUInt64LittleEndian(entry[0x10..]);
-            if (attributeId != PortAttributeIdPcm || valueAddress == 0 || valueSize < 8)
+            if (valueAddress == 0)
+            {
+                continue;
+            }
+
+            if (attributeId is PortAttributeIdGain or PortAttributeIdPassthrough or PortAttributeIdAmbisonics)
+            {
+                if (valueSize < sizeof(uint) || !ctx.Memory.TryRead(valueAddress, word))
+                {
+                    continue;
+                }
+
+                var value = BinaryPrimitives.ReadUInt32LittleEndian(word);
+                switch (attributeId)
+                {
+                    case PortAttributeIdGain:
+                        var gain = BitConverter.UInt32BitsToSingle(value);
+                        if (float.IsFinite(gain))
+                        {
+                            port.Gain = gain;
+                        }
+
+                        break;
+                    case PortAttributeIdPassthrough:
+                        port.Passthrough = value;
+                        break;
+                    default:
+                        port.Ambisonics = value;
+                        break;
+                }
+
+                continue;
+            }
+
+            if (attributeId != PortAttributeIdPcm || valueSize < 8)
             {
                 continue;
             }
@@ -1050,6 +1107,28 @@ public static class AudioOut2Exports
         }
     }
 
+    internal static double DeviceSlotFreeThreshold(uint grainSamples, uint frequency, uint queueDepth) =>
+        DeviceCushionMilliseconds + (grainSamples * 1000.0 / frequency * Math.Max((long)queueDepth - 1, 0));
+
+    private static void WaitForDeviceSlot(ContextState context)
+    {
+        var backend = ResolveContextBackend(context, out _);
+        if (backend is null)
+        {
+            return;
+        }
+
+        var limit = context.DeviceSlotFreeMilliseconds;
+        var deadline = Stopwatch.GetTimestamp() + (Stopwatch.Frequency / 4);
+        int queued;
+        while ((queued = backend.QueuedMilliseconds) > limit &&
+               Stopwatch.GetTimestamp() < deadline &&
+               !HostSessionControl.IsShutdownRequested)
+        {
+            Thread.Sleep((int)Math.Clamp(Math.Ceiling(queued - limit), 1, 50));
+        }
+    }
+
     private static uint QueuedGrains(ContextState context)
     {
         if (context.DevicePaced)
@@ -1087,7 +1166,9 @@ public static class AudioOut2Exports
                     if (port.ContextHandle != context.Handle ||
                         port.PcmAddress == 0 ||
                         Interlocked.Exchange(ref port.PcmPending, 0) == 0 ||
-                        !TryDecodeDataFormat(port.DataFormat, out var ch, out var bps, out var isFloat))
+                        !TryDecodeDataFormat(port.DataFormat, out var ch, out var bps, out var isFloat) ||
+                        !TryGetStereoGains(port.PortType, ch, port.Gain, port.Ambisonics, port.Passthrough,
+                            out var leftGain, out var rightGain))
                     {
                         continue;
                     }
@@ -1111,7 +1192,8 @@ public static class AudioOut2Exports
                         ch,
                         bps,
                         isFloat,
-                        additive: mixedPorts > 0);
+                        leftGain,
+                        rightGain);
                     mixedPorts++;
                 }
 
@@ -1162,20 +1244,69 @@ public static class AudioOut2Exports
         }
     }
 
-    private static bool IsMainOrBgmPort(ushort portType)
+    internal static bool RoutesToSpeakers(ushort portType) => (portType & 0xFF) is 0 or 1 or 2;
+
+    internal static (float Gain, uint Ambisonics, uint Passthrough)? PortMixAttributes(ulong portHandle) =>
+        Ports.TryGetValue(portHandle, out var port) ? (port.Gain, port.Ambisonics, port.Passthrough) : null;
+
+    internal static bool TryGetStereoGains(
+        ushort portType,
+        int channels,
+        float gain,
+        uint ambisonics,
+        uint passthrough,
+        out float left,
+        out float right)
     {
-        var kind = portType & 0xFF;
+        left = 0f;
-        return kind is 0 or 1;
+        right = 0f;
+        if (!RoutesToSpeakers(portType) || gain == 0f)
+        {
+            return false;
+        }
+
+        if (!IsObjectPort(portType) || channels != 1)
+        {
+            left = gain;
+            right = gain;
+            return true;
+        }
+
+        if (ambisonics == AmbisonicsNone)
+        {
+            left = passthrough == PassthroughRight ? 0f : passthrough == PassthroughLeft ? gain : gain * HalfPower;
+            right = passthrough == PassthroughLeft ? 0f : passthrough == PassthroughRight ? gain : gain * HalfPower;
+            return true;
+        }
+
+        var acn = ambisonics >= AmbisonicsAcnBase;
+        var component = acn ? ambisonics - AmbisonicsAcnBase : ambisonics;
+        if (component == 0)
+        {
+            left = acn ? gain * HalfPower : gain;
+            right = left;
+            return true;
+        }
+
+        if (component == (acn ? 1u : 2u))
+        {
+            left = gain * HalfPower;
+            right = -left;
+            return true;
+        }
+
+        return false;
     }
 
-    private static void MixPortIntoStereo(
+    internal static void MixPortIntoStereo(
         ReadOnlySpan<byte> source,
         Span<float> mix,
         int frames,
         int channels,
         int bytesPerSample,
         bool isFloat,
-        bool additive)
+        float leftGain,
+        float rightGain)
     {
         var frameSize = channels * bytesPerSample;
         for (var frame = 0; frame < frames; frame++)
@@ -1204,16 +1335,8 @@ public static class AudioOut2Exports
                     : ReadNormalizedSample(frameBytes, 1, bytesPerSample, isFloat);
             }
 
-            if (additive)
+            mix[frame * 2] += left * leftGain;
-            {
+            mix[(frame * 2) + 1] += right * rightGain;
-                mix[frame * 2] += left;
-                mix[(frame * 2) + 1] += right;
-            }
-            else
-            {
-                mix[frame * 2] = left;
-                mix[(frame * 2) + 1] = right;
-            }
         }
     }
 

src/SharpEmu.Libs/Diagnostics/DccWriterTrace.cs

@@ -9,15 +9,19 @@ namespace SharpEmu.Libs.Diagnostics;
 
 internal static class DccWriterTrace
 {
-    private const int MaxReports = 64;
+    private const int MaxReports = 256;
     private const int MaxFrames = 12;
 
     private static readonly bool DccEnabled =
         Environment.GetEnvironmentVariable("SHARPEMU_TRACE_DCC_WRITERS") == "1";
 
-    private static readonly ulong TargetAddress = ParseAddress(Environment.GetEnvironmentVariable("SHARPEMU_TRACE_WRITER_ADDRESS"));
+    private static readonly ulong[] TargetAddresses = (Environment.GetEnvironmentVariable("SHARPEMU_TRACE_WRITER_ADDRESS") ?? string.Empty)
+        .Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
+        .Select(ParseAddress)
+        .Where(address => address != 0)
+        .ToArray();
 
-    public static readonly bool Enabled = DccEnabled || TargetAddress != 0;
+    public static readonly bool Enabled = DccEnabled || TargetAddresses.Length != 0;
 
     [ThreadStatic]
     public static ulong CurrentProgram;
@@ -43,7 +47,7 @@ internal static class DccWriterTrace
 
     public static void Record(IGuestImageCache images, ulong address, ulong size)
     {
-        var targeted = TargetAddress != 0 && TargetAddress >= address && TargetAddress - address < size;
+        var targeted = TargetAddresses.Any(target => target >= address && target - address < size);
         if (_reported.Count >= MaxReports || (!targeted && !(DccEnabled && images.OverlapsDccMetadata(address, size))) ||
             !_reported.Add((address, size, CurrentProgram)))
         {

src/SharpEmu.Libs/Diagnostics/GpuReadTrace.cs

@@ -17,6 +17,30 @@ internal static class GpuReadTrace
     public static string? CurrentStage;
 
     private static readonly HashSet<(ulong Shader, ulong Page, bool Table)> _reported = new();
+    private static readonly Dictionary<ulong, (long Reads, long Changes, uint Last, uint First, ulong Shader)> _values = new();
+    private static long _nextValueReport = System.Diagnostics.Stopwatch.GetTimestamp();
+
+    public static void RecordValue(ulong address, uint word)
+    {
+        lock (_values)
+        {
+            _values[address] = _values.TryGetValue(address, out var entry)
+                ? (entry.Reads + 1, entry.Changes + (entry.Last != word ? 1 : 0), word, entry.First, entry.Shader)
+                : (1, 0, word, word, CurrentShader);
+            var now = System.Diagnostics.Stopwatch.GetTimestamp();
+            if (now < _nextValueReport)
+            {
+                return;
+            }
+
+            _nextValueReport = now + System.Diagnostics.Stopwatch.Frequency * 5;
+            foreach (var (key, value) in _values.OrderByDescending(pair => pair.Value.Reads).Take(16))
+            {
+                Console.Error.WriteLine(
+                    $"[GPU][SYNC_READ_VALUE] address=0x{key:X16} reads={value.Reads} changes={value.Changes} first=0x{value.First:X8} last=0x{value.Last:X8} shader=0x{value.Shader:X16}");
+            }
+        }
+    }
 
     public static void Record(ulong address, bool table)
     {

src/SharpEmu.Libs/Gpu/Buffers/GuestBufferCache.cs

@@ -460,6 +460,72 @@ public sealed unsafe class GuestBufferCache : IGuestBufferStore, IDisposable
         return true;
     }
 
+    public const ulong MaxHostCopyWords = 64 * 1024;
+
+    public bool TryCopyWordsOnHost(ulong destination, ulong source, ulong sourceWords, ulong words)
+    {
+        if (destination == 0 || source == 0 || sourceWords == 0 || words == 0 || ((destination | source) & 3) != 0 ||
+            words > MaxHostCopyWords || sourceWords > MaxHostCopyWords)
+        {
+            return false;
+        }
+
+        var size = words * sizeof(uint);
+        var sourceSize = Math.Min(sourceWords, words) * sizeof(uint);
+        if (size > ulong.MaxValue - destination || sourceSize > ulong.MaxValue - source ||
+            (source < destination + size && destination < source + sourceSize))
+        {
+            return false;
+        }
+
+        var images = RequireImageCache();
+        var sourceRegion = images.QueryRegion(source, sourceSize);
+        var destinationRegion = images.QueryRegion(destination, size);
+        if (HasGpuDirtyBytes(source, sourceSize) || HasGpuDirtyBytes(destination, size) ||
+            sourceRegion.GpuImageBytes || destinationRegion.GpuImageBytes)
+        {
+            return false;
+        }
+
+        var pattern = System.Buffers.ArrayPool<byte>.Shared.Rent((int)sourceSize);
+        var chunk = System.Buffers.ArrayPool<byte>.Shared.Rent((int)Math.Min(size, 64UL * 1024));
+        try
+        {
+            if (!_backing.TryReadBacking(source, pattern.AsSpan(0, (int)sourceSize)))
+            {
+                return false;
+            }
+
+            if (destinationRegion.ImageBytes)
+            {
+                images.InvalidateMemory(destination, size);
+            }
+
+            var chunkLength = (ulong)(chunk.Length - chunk.Length % sizeof(uint));
+            for (ulong offset = 0; offset < size;)
+            {
+                var length = (int)Math.Min(size - offset, chunkLength);
+                for (var filled = 0; filled < length;)
+                {
+                    var patternOffset = (int)((offset + (ulong)filled) % sourceSize);
+                    var copied = Math.Min(length - filled, (int)sourceSize - patternOffset);
+                    pattern.AsSpan(patternOffset, copied).CopyTo(chunk.AsSpan(filled, copied));
+                    filled += copied;
+                }
+
+                WriteHostMemory(destination + offset, chunk.AsSpan(0, length));
+                offset += (ulong)length;
+            }
+
+            return true;
+        }
+        finally
+        {
+            System.Buffers.ArrayPool<byte>.Shared.Return(pattern);
+            System.Buffers.ArrayPool<byte>.Shared.Return(chunk);
+        }
+    }
+
     public void CopyBuffer(ulong dstVaddr, ulong srcVaddr, ulong size, bool dstGds, bool srcGds)
     {
         var dstMemory = !dstGds;
@@ -557,7 +623,21 @@ public sealed unsafe class GuestBufferCache : IGuestBufferStore, IDisposable
     private ulong _bdaTouchTick = ulong.MaxValue;
     private ulong _bdaTouchMapping;
 
+    public static ulong MappingKey(IReadOnlyCollection<GuestSpan> spans)
+    {
+        var mapping = (ulong)spans.Count;
+        foreach (var span in spans)
+            mapping = (mapping ^ span.Address ^ (span.Size << 17)) * 0x100000001B3UL;
+        return mapping;
+    }
+
     public void PrepareBda(IEnumerable<GuestSpan> mapped)
+    {
+        var spans = mapped as IReadOnlyCollection<GuestSpan> ?? mapped.ToList();
+        PrepareBda(spans, MappingKey(spans));
+    }
+
+    public void PrepareBda(IReadOnlyCollection<GuestSpan> mapped, ulong mapping)
     {
         var traceAddress = GuestGpuMemoryHook.TraceAddress;
         var traceCovered = false;
@@ -572,10 +652,7 @@ public sealed unsafe class GuestBufferCache : IGuestBufferStore, IDisposable
         }
         else
         {
-            var spans = mapped as IReadOnlyCollection<GuestSpan> ?? mapped.ToList();
+            var spans = mapped;
-            var mapping = (ulong)spans.Count;
-            foreach (var span in spans)
-                mapping = (mapping ^ span.Address ^ (span.Size << 17)) * 0x100000001B3UL;
             if (_retirementPolicy.CurrentTick != _bdaTouchTick || mapping != _bdaTouchMapping)
             {
                 foreach (var span in spans)

src/SharpEmu.Libs/Gpu/Metal/MetalCommandStreamHost.Rendering.cs

@@ -1196,4 +1196,10 @@ internal sealed partial class MetalCommandStreamHost : IRenderHost, IShaderPipel
         _ = (address, size, fillValue);
         return false;
     }
+
+    bool IRenderHost.TryCopyWordsOnHost(ulong destination, ulong source, ulong sourceWords, ulong words)
+    {
+        _ = (destination, source, sourceWords, words);
+        return false;
+    }
 }

src/SharpEmu.Libs/Gpu/Pipelines/BoundedFillDetector.cs

@@ -26,8 +26,104 @@ public sealed record BoundedFill(
     FillWord[]? Pattern = null,
     FillWord? PatternLength = null);
 
+public sealed record BoundedCopy(
+    uint GroupScalarRegister,
+    FillWord Count,
+    FillWord Modulus,
+    FillWord[] Source,
+    FillWord[] Destination);
+
 public static class BoundedFillDetector
 {
+    private static readonly string[] ModuloCopyOpcodes =
+    [
+        "VLshlAddU32", "SBufferLoadDword", "VCmpxGtU32", "SCbranchExecz", "SBufferLoadDword",
+        "VCvtF32U32", "SCmpLgU32", "SCselectB64", "VRcpIflagF32", "VMulF32", "VCvtU32F32", "VMadU64U32", "VCmpNeU32", "VSubI32",
+        "VCndmaskB32", "VMulHiU32", "VSubI32", "VAddI32", "VCndmaskB32", "VMulHiU32", "VMulLoU32", "VSubI32", "VCmpGeU32",
+        "VCmpLeU32", "SAndB64", "VAddcU32", "VAddCoCiU32", "VCndmaskB32", "VMulLoU32", "VSubI32",
+        "BufferLoadFormatX", "BufferStoreFormatX", "SEndpgm",
+    ];
+
+    public static BoundedCopy? DetectCopy(Gen5ShaderProgram program)
+    {
+        var instructions = program.Instructions
+            .Where(instruction => instruction.Opcode is not ("SWaitcnt" or "STtraceData" or "SInstPrefetch") &&
+                !(instruction.Opcode == "SMovB32" && instruction.Destinations is [{ Kind: Gen5OperandKind.ScalarRegister, Value: MarkerRegister }]))
+            .ToArray();
+        if (!instructions.Select(instruction => instruction.Opcode).SequenceEqual(ModuloCopyOpcodes))
+        {
+            return null;
+        }
+
+        var countLoad = instructions[1];
+        var modulusLoad = instructions[4];
+        if (instructions[0].Destinations is not [{ Kind: Gen5OperandKind.VectorRegister } index] ||
+            instructions[0].Sources is not [{ Kind: Gen5OperandKind.ScalarRegister } group, { Kind: Gen5OperandKind.EncodedConstant, Value: Shift64 },
+                { Kind: Gen5OperandKind.VectorRegister, Value: ThreadIndexRegister }] ||
+            countLoad.Destinations is not [{ Kind: Gen5OperandKind.ScalarRegister } count] ||
+            modulusLoad.Destinations is not [{ Kind: Gen5OperandKind.ScalarRegister } modulus] ||
+            countLoad.Sources is not [{ Kind: Gen5OperandKind.ScalarRegister } constants, _] ||
+            modulusLoad.Sources is not [{ Kind: Gen5OperandKind.ScalarRegister } modulusConstants, _] ||
+            modulusConstants.Value != constants.Value ||
+            instructions[2].Sources is not [{ Kind: Gen5OperandKind.ScalarRegister } limit, { Kind: Gen5OperandKind.VectorRegister } compared] ||
+            limit.Value != count.Value || compared.Value != index.Value ||
+            instructions[5].Sources is not [{ Kind: Gen5OperandKind.ScalarRegister } converted] || converted.Value != modulus.Value ||
+            instructions[6].Sources is not [{ Kind: Gen5OperandKind.EncodedConstant, Value: ZeroConstant }, { Kind: Gen5OperandKind.ScalarRegister } tested] ||
+            tested.Value != modulus.Value)
+        {
+            return null;
+        }
+
+        foreach (var at in new[] { 11, 20, 23, 28 })
+        {
+            if (instructions[at].Sources is not [{ Kind: Gen5OperandKind.ScalarRegister } multiplier, ..] || multiplier.Value != modulus.Value)
+            {
+                return null;
+            }
+        }
+
+        var load = instructions[30];
+        var store = instructions[31];
+        if (instructions[29].Destinations is not [{ Kind: Gen5OperandKind.VectorRegister } remainder] ||
+            instructions[29].Sources is not [{ Kind: Gen5OperandKind.VectorRegister } dividend, { Kind: Gen5OperandKind.VectorRegister }] ||
+            dividend.Value != index.Value ||
+            load.Control is not Gen5BufferMemoryControl { DwordCount: 1, OffsetBytes: 0, IndexEnabled: true, OffsetEnabled: false, Typed: false } loadControl ||
+            store.Control is not Gen5BufferMemoryControl { DwordCount: 1, OffsetBytes: 0, IndexEnabled: true, OffsetEnabled: false, Typed: false } storeControl ||
+            load.Sources is not [_, _, { Kind: Gen5OperandKind.EncodedConstant, Value: ZeroConstant }] ||
+            store.Sources is not [_, _, { Kind: Gen5OperandKind.EncodedConstant, Value: ZeroConstant }] ||
+            loadControl.VectorAddress != remainder.Value || storeControl.VectorAddress != index.Value ||
+            storeControl.VectorData != loadControl.VectorData)
+        {
+            return null;
+        }
+
+        var branch = instructions[3];
+        if (branch.Pc + sizeof(uint) + (uint)((short)(branch.Words[0] & 0xFFFF) * sizeof(uint)) != instructions[^1].Pc)
+        {
+            return null;
+        }
+
+        var resourceRegisters = Enumerable.Range(0, 4)
+            .SelectMany(word => new[] { loadControl.ScalarResource + (uint)word, storeControl.ScalarResource + (uint)word });
+        var constantRegisters = Enumerable.Range(0, 4).Select(word => constants.Value + (uint)word);
+        if (resourceRegisters.Any(WrittenScalars(instructions, instructions.Length).Contains) ||
+            constantRegisters.Any(WrittenScalars(instructions, 4).Contains) ||
+            WrittenScalars(instructions[5..29], 24).Contains(modulus.Value) ||
+            countLoad.Control is not Gen5ScalarMemoryControl { DynamicOffsetRegister: null, ImmediateOffsetBytes: >= 0 } countControl ||
+            modulusLoad.Control is not Gen5ScalarMemoryControl { DynamicOffsetRegister: null, ImmediateOffsetBytes: >= 0 } modulusControl)
+        {
+            return null;
+        }
+
+        FillWord User(uint register) => new(FillWordSource.UserData, register, 0, 0);
+        return new BoundedCopy(
+            group.Value,
+            new FillWord(FillWordSource.BufferResource, constants.Value, 0, countControl.ImmediateOffsetBytes),
+            new FillWord(FillWordSource.BufferResource, constants.Value, 0, modulusControl.ImmediateOffsetBytes),
+            [.. Enumerable.Range(0, 4).Select(word => User(loadControl.ScalarResource + (uint)word))],
+            [.. Enumerable.Range(0, 4).Select(word => User(storeControl.ScalarResource + (uint)word))]);
+    }
+
     private const uint Shift64 = 134;
     private const uint ZeroConstant = 128;
     private const uint NullScalar = 125;

src/SharpEmu.Libs/Gpu/Pipelines/ShaderPrewarmList.cs

@@ -1,6 +1,7 @@
 // Copyright (C) 2026 SharpEmu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+using System.Globalization;
 using System.IO.Hashing;
 using System.Text;
 using SharpEmu.HLE;
@@ -141,6 +142,7 @@ internal sealed class ShaderPrewarmList : IDisposable
 {
     public const string FileName = "shader-prewarm.bin";
     public const string StampFileName = "shader-prewarm.stamp";
+    public const string ProgressFileName = "shader-prewarm.progress";
 
     private const uint Magic = 0x57504553;
     private const uint FormatVersion = 1;
@@ -151,16 +153,19 @@ internal sealed class ShaderPrewarmList : IDisposable
     private readonly object _gate = new();
     private readonly FileStream _file;
     private readonly string _stampPath;
+    private readonly string _progressPath;
+    private readonly object _progressGate = new();
     private readonly HashSet<(ulong Hash, uint CodeSize, ulong Address)> _codes = [];
     private readonly HashSet<ulong> _computes = [];
     private readonly Dictionary<(ulong Hash, uint CodeSize, ulong Address), ShaderCodeCapture> _loadedCodes = new();
     private readonly List<ComputePrewarmRecord> _loadedComputes = [];
     private bool _failed;
 
-    private ShaderPrewarmList(FileStream file, string stampPath)
+    private ShaderPrewarmList(FileStream file, string stampPath, string progressPath)
     {
         _file = file;
         _stampPath = stampPath;
+        _progressPath = progressPath;
     }
 
     public int LoadedComputeCount => _loadedComputes.Count;
@@ -172,7 +177,7 @@ internal sealed class ShaderPrewarmList : IDisposable
             Directory.CreateDirectory(directory);
             var path = Path.Combine(directory, FileName);
             var file = new FileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read);
-            var list = new ShaderPrewarmList(file, Path.Combine(directory, StampFileName));
+            var list = new ShaderPrewarmList(file, Path.Combine(directory, StampFileName), Path.Combine(directory, ProgressFileName));
             try
             {
                 list.Load();
@@ -230,6 +235,93 @@ internal sealed class ShaderPrewarmList : IDisposable
         }
     }
 
+    public static ulong Identity(ComputePrewarmRecord record) => XxHash3.HashToUInt64(SerializeCompute(record));
+
+    public HashSet<ulong> ReadProgress(string stamp)
+    {
+        var completed = new HashSet<ulong>();
+        lock (_progressGate)
+        {
+            try
+            {
+                if (!File.Exists(_progressPath))
+                {
+                    return completed;
+                }
+
+                var lines = File.ReadAllLines(_progressPath);
+                if (lines.Length == 0 || lines[0] != ProgressKey(stamp))
+                {
+                    File.Delete(_progressPath);
+                    return completed;
+                }
+
+                for (var index = 1; index < lines.Length; index++)
+                {
+                    if (ulong.TryParse(lines[index], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var identity))
+                    {
+                        completed.Add(identity);
+                    }
+                }
+            }
+            catch (Exception exception) when (exception is IOException or UnauthorizedAccessException)
+            {
+                completed.Clear();
+            }
+        }
+
+        return completed;
+    }
+
+    public void AppendProgress(string stamp, IReadOnlyCollection<ulong> identities)
+    {
+        if (identities.Count == 0)
+        {
+            return;
+        }
+
+        lock (_progressGate)
+        {
+            try
+            {
+                var lines = new List<string>(identities.Count + 1);
+                if (!File.Exists(_progressPath))
+                {
+                    lines.Add(ProgressKey(stamp));
+                }
+
+                foreach (var identity in identities)
+                {
+                    lines.Add(identity.ToString("X16", CultureInfo.InvariantCulture));
+                }
+
+                File.AppendAllLines(_progressPath, lines);
+            }
+            catch (Exception exception) when (exception is IOException or UnauthorizedAccessException)
+            {
+                Console.Error.WriteLine($"[LOADER][WARN] Shader prewarm progress write failed: {exception.Message}");
+            }
+        }
+    }
+
+    public void ClearProgress()
+    {
+        lock (_progressGate)
+        {
+            try
+            {
+                File.Delete(_progressPath);
+            }
+            catch (Exception exception) when (exception is IOException or UnauthorizedAccessException)
+            {
+                Console.Error.WriteLine($"[LOADER][WARN] Shader prewarm progress clear failed: {exception.Message}");
+            }
+        }
+    }
+
+    private static string ProgressKey(string stamp) =>
+        XxHash3.HashToUInt64(Encoding.UTF8.GetBytes(stamp)).ToString("X16", CultureInfo.InvariantCulture);
+
     public void RecordCompute(ShaderCodeCapture code, ComputePrewarmRecord record)
     {
         var payload = SerializeCompute(record);

src/SharpEmu.Libs/Gpu/Pipelines/ShaderProgramCache.cs

@@ -87,6 +87,7 @@ internal sealed class ProgramSourceEntry
     public required bool HasBitwiseExclusiveOr { get; init; }
     public ConstantFill? ConstantFill { get; init; }
     public BoundedFill? BoundedFill { get; init; }
+    public BoundedCopy? BoundedCopy { get; init; }
     public EmbeddedVertexFetchPlan? EmbeddedFetch { get; init; }
     public ShaderVertexInput[] VertexInputs { get; init; } = [];
     public List<ProgramPermutation> Permutations { get; } = new(8);
@@ -383,6 +384,7 @@ internal sealed class ShaderProgramCache
             HasBitwiseExclusiveOr = exclusiveOr,
             ConstantFill = source.Stage == ShaderStage.Compute ? ConstantFillDetector.Detect(program) : null,
             BoundedFill = source.Stage == ShaderStage.Compute ? BoundedFillDetector.Detect(program) : null,
+            BoundedCopy = source.Stage == ShaderStage.Compute ? BoundedFillDetector.DetectCopy(program) : null,
             EmbeddedFetch = fetch,
             VertexInputs = vertexInputs,
         };
@@ -837,6 +839,7 @@ internal sealed class ShaderProgramCache
             HasBitwiseExclusiveOr = entry.HasBitwiseExclusiveOr,
             ConstantFill = entry.ConstantFill,
             BoundedFill = entry.BoundedFill,
+            BoundedCopy = entry.BoundedCopy,
             Buffers = buffers,
             Images = images,
             SamplerCount = info.Samplers.Count,

src/SharpEmu.Libs/Gpu/Rendering/IRenderHost.cs

@@ -188,5 +188,7 @@ public interface IRenderHost
 
     bool TryFillDccMetadata(ulong address, ulong size, uint fillValue);
 
+    bool TryCopyWordsOnHost(ulong destination, ulong source, ulong sourceWords, ulong words);
+
     Exception Fatal(string message);
 }

src/SharpEmu.Libs/Gpu/Rendering/RenderExecutor.Compute.cs

@@ -101,6 +101,12 @@ public sealed partial class RenderExecutor
             return;
         }
 
+        if (indirectArgumentsAddress == 0 && TryConsumeBoundedCopy(input, groupsX, groupsY, groupsZ, dispatchInitiator))
+        {
+            _host.ResetBindings();
+            return;
+        }
+
         if (indirectArgumentsAddress == 0 && TryConsumeImageClear(input, groupsX, groupsY, groupsZ, dispatchInitiator))
         {
             _host.ResetBindings();
@@ -552,6 +558,71 @@ public sealed partial class RenderExecutor
         return consumed;
     }
 
+    private bool TryConsumeBoundedCopy(ComputeInputInfo input, uint groupsX, uint groupsY, uint groupsZ, uint dispatchInitiator)
+    {
+        var program = input.Stage.Program!;
+        if (program.BoundedCopy is not { } copy || !BoundedCopyEnabled)
+        {
+            return false;
+        }
+
+        if (program.UserDataBase != 0 || copy.GroupScalarRegister != (uint)input.WorkgroupRegister || !input.GroupIdX || input.GroupIdY || input.GroupIdZ ||
+            input.ThreadIdCount < 1 || input.ThreadsX != ImageClearWaveSize || input.ThreadsY != 1 || input.ThreadsZ != 1 ||
+            groupsX == 0 || groupsY != 1 || groupsZ != 1)
+        {
+            return RefuseBoundedFill(program, $"copy shape dispatch={groupsX}x{groupsY}x{groupsZ} local={input.ThreadsX}x{input.ThreadsY}x{input.ThreadsZ}");
+        }
+
+        var userData = input.Stage.Resources.UserData;
+        Span<uint> sourceWords = stackalloc uint[4];
+        Span<uint> destinationWords = stackalloc uint[4];
+        for (var word = 0; word < 4; word++)
+        {
+            if (!TryResolveFillWord(copy.Source[word], userData, out sourceWords[word]) ||
+                !TryResolveFillWord(copy.Destination[word], userData, out destinationWords[word]))
+            {
+                return RefuseBoundedFill(program, $"copy descriptor word {word} unreadable");
+            }
+        }
+
+        if (!TryResolveFillWord(copy.Count, userData, out var count) || !TryResolveFillWord(copy.Modulus, userData, out var modulus))
+        {
+            return RefuseBoundedFill(program, "copy range unreadable");
+        }
+
+        var source = BufferDescriptorWords.From(sourceWords);
+        var destination = BufferDescriptorWords.From(destinationWords);
+        if (!IsPlainWordBuffer(source) || !IsPlainWordBuffer(destination) || source.Format != destination.Format ||
+            modulus == 0 || modulus > source.RecordCount)
+        {
+            return RefuseBoundedFill(program,
+                $"copy src=0x{source.Address:X}/{source.Format}/{source.Stride}/{source.OutOfBounds} dst=0x{destination.Address:X}/{destination.Format}/{destination.Stride}/{destination.OutOfBounds} " +
+                $"modulus={modulus} records={source.RecordCount}");
+        }
+
+        var threads = (dispatchInitiator & DispatchInitiatorUseThreadDimensions) != 0 ? groupsX : (ulong)groupsX * input.ThreadsX;
+        var words = Math.Min(Math.Min((ulong)count, threads), destination.RecordCount);
+        if (words == 0)
+        {
+            return false;
+        }
+
+        var consumed = _host.TryCopyWordsOnHost(destination.Address, source.Address, modulus, words);
+        if (RenderTrace.Enabled)
+        {
+            RenderTrace.Write(
+                $"Bounded copy: shader=0x{program.Hash:X16} src=0x{source.Address:X16} dst=0x{destination.Address:X16} words={words} modulus={modulus} consumed={consumed}");
+        }
+
+        return consumed || RefuseBoundedFill(program, $"copy refused by the host dst=0x{destination.Address:X} words={words} modulus={modulus}");
+    }
+
+    private static readonly bool BoundedCopyEnabled = Environment.GetEnvironmentVariable("SHARPEMU_HOST_BOUNDED_COPY") != "0";
+
+    private static bool IsPlainWordBuffer(BufferDescriptorWords descriptor) =>
+        descriptor.Stride == sizeof(uint) && !descriptor.SwizzleEnabled && !descriptor.AddThreadId && descriptor.OutOfBounds == 0 &&
+        descriptor.Type == 0 && (descriptor.Address & 3) == 0 && descriptor.Format is Format32UInt or Format32SInt or Format32Float;
+
     private static bool RefuseBoundedFill(ShaderProgramInfo program, string reason)
     {
         Diagnostics.DccWriterTrace.Refuse(program.Hash, reason);

src/SharpEmu.Libs/Gpu/Rendering/ShaderStageResources.cs

@@ -58,6 +58,7 @@ public class ShaderProgramInfo
     public bool HasBitwiseExclusiveOr { get; init; }
     public Pipelines.ConstantFill? ConstantFill { get; init; }
     public Pipelines.BoundedFill? BoundedFill { get; init; }
+    public Pipelines.BoundedCopy? BoundedCopy { get; init; }
     public BufferResourceInfo[] Buffers { get; init; } = [];
     public ImageResourceInfo[] Images { get; init; } = [];
     public int SamplerCount { get; init; }

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.CommandStream.cs

@@ -40,6 +40,7 @@ internal static unsafe partial class VulkanVideoPresenter
         }
 
         EnsureStarted(1280, 720);
+        WaitForShaderPrewarm("first GPU submission");
         // Queue publication precedes device initialization; only the render thread consumes it.
         lock (_gate)
         {
@@ -117,6 +118,7 @@ internal static unsafe partial class VulkanVideoPresenter
         _ = width;
         _ = height;
         _ = pitchInPixel;
+        WaitForShaderPrewarm("first flip");
         if (!IsKnownDisplayBuffer(address) || !TryGetActivePresenter(out var presenter))
         {
             return false;

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.Descriptors.cs

@@ -402,8 +402,7 @@ internal static unsafe partial class VulkanVideoPresenter
             }
             using var profileScope = BufferUploadProfile.BeginSweep(vertexProgramHash, pixelProgramHash, computeProgramHash);
             var memory = GuestGpuMemoryHook.Current ?? throw SubmissionScheduler.Fatal("A device-address program needs the guest GPU memory registry.");
-            var spans = new List<GuestSpan>();
+            var spans = DeviceAddressSpans(memory);
-            memory.ForEachSpan((address, size) => spans.Add(new GuestSpan(address, size)));
             var traceAddress = GuestGpuMemoryHook.TraceAddress;
             if (traceAddress != 0)
             {
@@ -420,7 +419,29 @@ internal static unsafe partial class VulkanVideoPresenter
             if (traceAddress != 0 && !memory.Covers(traceAddress, 1))
                 GuestGpuMemoryHook.Trace(traceAddress, 1,
                     $"device-address-mapping-check readable={_guestMemory.CanRead(traceAddress, 1)} backed={_guestBacking.IsBackedView(traceAddress)}");
-            _bufferCache.PrepareBda(spans);
+            _bufferCache.PrepareBda(spans, _bdaSpanMapping);
+        }
+
+        private List<GuestSpan>? _bdaSpans;
+        private GuestGpuMemory? _bdaSpanMemory;
+        private long _bdaSpanVersion = -1;
+        private ulong _bdaSpanMapping;
+
+        private List<GuestSpan> DeviceAddressSpans(GuestGpuMemory memory)
+        {
+            var version = memory.SpanVersion;
+            if (_bdaSpans is { } cached && ReferenceEquals(_bdaSpanMemory, memory) && _bdaSpanVersion == version)
+            {
+                return cached;
+            }
+
+            var spans = new List<GuestSpan>();
+            memory.ForEachSpan((address, size) => spans.Add(new GuestSpan(address, size)));
+            _bdaSpans = spans;
+            _bdaSpanMemory = memory;
+            _bdaSpanVersion = version;
+            _bdaSpanMapping = GuestBufferCache.MappingKey(spans);
+            return spans;
         }
 
         public void BindResources(IPreparedBindings prepared)

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.Pipelines.cs

@@ -100,6 +100,7 @@ internal static unsafe partial class VulkanVideoPresenter
         {
             using var profile = ResourceMaterializationProfile.Measure(ResourceMaterializationProfile.Phase.GuestRead);
             word = 0;
+            var synchronized = false;
             if (IsCleanReadPage(address, sizeof(uint)))
             {
                 if (TryGetAliasPointer(address, sizeof(uint), out var alias))
@@ -132,6 +133,8 @@ internal static unsafe partial class VulkanVideoPresenter
                     {
                         return false;
                     }
+
+                    synchronized = true;
                 }
                 else
                 {
@@ -146,6 +149,11 @@ internal static unsafe partial class VulkanVideoPresenter
             }
 
             word = System.Buffers.Binary.BinaryPrimitives.ReadUInt32LittleEndian(bytes);
+            if (Diagnostics.GpuReadTrace.Enabled && synchronized)
+            {
+                Diagnostics.GpuReadTrace.RecordValue(address, word);
+            }
+
             return true;
         }
 

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.Present.cs

@@ -157,8 +157,73 @@ internal static unsafe partial class VulkanVideoPresenter
         _guestFlipVersionSequence = 0;
     }
 
+    private static readonly bool _shaderPrewarmWaitDisabled =
+        Environment.GetEnvironmentVariable("SHARPEMU_SHADER_PREWARM_WAIT") == "0";
+    private static bool _shaderPrewarmDecided;
+    private static bool _shaderPrewarmRunning;
+    private static bool _shaderPrewarmReleased;
+    private static int _shaderPrewarmHoldReported;
+    private static int _shaderPrewarmProgress;
+    private static int _shaderPrewarmTotal;
+
+    private static void SetShaderPrewarmState(bool running)
+    {
+        lock (_gate)
+        {
+            _shaderPrewarmDecided = true;
+            _shaderPrewarmRunning = running;
+            Volatile.Write(ref _shaderPrewarmReleased, !running);
+            System.Threading.Monitor.PulseAll(_gate);
+        }
+    }
+
+    internal static void WaitForShaderPrewarm(string holder)
+    {
+        if (_shaderPrewarmWaitDisabled || Volatile.Read(ref _shaderPrewarmReleased))
+        {
+            return;
+        }
+
+        var started = System.Diagnostics.Stopwatch.GetTimestamp();
+        var reported = started;
+        var reporter = false;
+        lock (_gate)
+        {
+            while (_thread is not null && (!_shaderPrewarmDecided || _shaderPrewarmRunning) &&
+                   !_closed && _presenterStartupFailure is null &&
+                   !HostSessionControl.IsShutdownRequested && !Volatile.Read(ref _presenterCloseRequested))
+            {
+                if (!reporter && _shaderPrewarmRunning &&
+                    Interlocked.Exchange(ref _shaderPrewarmHoldReported, 1) == 0)
+                {
+                    reporter = true;
+                    Console.Error.WriteLine(
+                        $"[LOADER][INFO] Shader prewarm: holding the game at its {holder} until it finishes.");
+                }
+
+                System.Threading.Monitor.Wait(_gate, 1000);
+                if (reporter && System.Diagnostics.Stopwatch.GetElapsedTime(reported) >= TimeSpan.FromSeconds(5))
+                {
+                    reported = System.Diagnostics.Stopwatch.GetTimestamp();
+                    var total = Volatile.Read(ref _shaderPrewarmTotal);
+                    var done = Volatile.Read(ref _shaderPrewarmProgress);
+                    Console.Error.WriteLine(
+                        $"[LOADER][INFO] Shader prewarm: {done}/{total} ({(total == 0 ? 0 : done * 100 / total)}%)");
+                }
+            }
+        }
+
+        if (reporter)
+        {
+            Console.Error.WriteLine(string.Create(
+                System.Globalization.CultureInfo.InvariantCulture,
+                $"[LOADER][INFO] Shader prewarm: game released after {System.Diagnostics.Stopwatch.GetElapsedTime(started).TotalSeconds:F1}s."));
+        }
+    }
+
     public static void HideSplashScreen()
     {
+        WaitForShaderPrewarm("splash screen");
         lock (_gate)
         {
             _splashHidden = true;

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.Rendering.cs

@@ -1200,5 +1200,8 @@ internal static unsafe partial class VulkanVideoPresenter
             _bufferCache.FillDccMetadata(address, size, fillValue);
             return true;
         }
+
+        public bool TryCopyWordsOnHost(ulong destination, ulong source, ulong sourceWords, ulong words) =>
+            _bufferCache.TryCopyWordsOnHost(destination, source, sourceWords, words);
     }
 }

src/SharpEmu.Libs/VideoOut/VulkanVideoPresenter.ShaderPrewarm.cs

@@ -17,6 +17,7 @@ internal static unsafe partial class VulkanVideoPresenter
     private sealed partial class Presenter
     {
         private const int MaxLoggedPrewarmFailures = 8;
+        private const int PrewarmProgressBatch = 256;
 
         private ShaderPrewarmList? _shaderPrewarmList;
         private ConcurrentDictionary<string, byte>? _prewarmedShaderIdentities;
@@ -27,16 +28,25 @@ internal static unsafe partial class VulkanVideoPresenter
         private int _shaderPrewarmCompiled;
         private int _shaderPrewarmFailed;
         private int _shaderPrewarmRuntimeHits;
+        private readonly ConcurrentQueue<ulong> _shaderPrewarmCompleted = new();
 
         ShaderPrewarmList? IShaderPipelineHost.ShaderPrewarm => Volatile.Read(ref _shaderPrewarmList);
 
         private void StartShaderPrewarm()
+        {
+            if (!StartShaderPrewarmCore())
+            {
+                SetShaderPrewarmState(false);
+            }
+        }
+
+        private bool StartShaderPrewarmCore()
         {
             if (_shaderPrewarmList is not null ||
                 _pipelineCacheShardDirectory is not null ||
                 Environment.GetEnvironmentVariable("SHARPEMU_SHADER_PREWARM") == "0")
             {
-                return;
+                return false;
             }
 
             var directory = Path.GetDirectoryName(VulkanPipelineCacheStorage.ResolvePath(
@@ -44,7 +54,7 @@ internal static unsafe partial class VulkanVideoPresenter
                 Environment.GetEnvironmentVariable("SHARPEMU_VK_PIPELINE_CACHE_PATH")));
             if (string.IsNullOrEmpty(directory) || ShaderPrewarmList.Open(directory) is not { } list)
             {
-                return;
+                return false;
             }
 
             _prewarmedShaderIdentities = new ConcurrentDictionary<string, byte>(StringComparer.Ordinal);
@@ -57,7 +67,7 @@ internal static unsafe partial class VulkanVideoPresenter
             {
                 list.WriteStamp(stamp);
                 _shaderPrewarmFinished = true;
-                return;
+                return false;
             }
 
             if (list.IsStampCurrent(stamp))
@@ -65,18 +75,31 @@ internal static unsafe partial class VulkanVideoPresenter
                 _shaderPrewarmFinished = true;
                 Console.Error.WriteLine(
                     $"[LOADER][INFO] Shader prewarm skipped: compute={list.LoadedComputeCount} reason=same-build-and-driver");
-                return;
+                return false;
             }
 
-            var work = new ConcurrentQueue<(ComputePrewarmRecord Record, ShaderCodeCapture Code)>(list.LoadedComputes());
+            var completed = list.ReadProgress(stamp);
+            var pending = list.LoadedComputes()
+                .Where(item => !completed.Contains(ShaderPrewarmList.Identity(item.Record)))
+                .ToList();
+            var started = Stopwatch.GetTimestamp();
+            if (pending.Count == 0)
+            {
+                FinishShaderPrewarm(list, stamp, started);
+                return false;
+            }
+
+            var work = new ConcurrentQueue<(ComputePrewarmRecord Record, ShaderCodeCapture Code)>(pending);
             var workerCount = Math.Clamp(Environment.ProcessorCount / 4, 1, 4);
             var remaining = workerCount;
-            var started = Stopwatch.GetTimestamp();
             var host = (IShaderPipelineHost)this;
             var sharedInt64Atomics = host.SharedInt64AtomicsEnabled;
             var execGuardElision = host.ExecGuardElisionEnabled;
+            Volatile.Write(ref _shaderPrewarmTotal, pending.Count);
+            Volatile.Write(ref _shaderPrewarmProgress, 0);
             Console.Error.WriteLine(
-                $"[LOADER][INFO] Shader prewarm started: compute={work.Count} workers={workerCount}");
+                $"[LOADER][INFO] Shader prewarm started: compute={pending.Count} resumed={completed.Count} workers={workerCount}");
+            SetShaderPrewarmState(true);
             _shaderPrewarmThreads = new Thread[workerCount];
             for (var index = 0; index < workerCount; index++)
             {
@@ -85,8 +108,14 @@ internal static unsafe partial class VulkanVideoPresenter
                     while (!_shaderPrewarmStopping && work.TryDequeue(out var item))
                     {
                         PrewarmComputePipeline(item.Record, item.Code, compiler, sharedInt64Atomics, execGuardElision);
+                        _shaderPrewarmCompleted.Enqueue(ShaderPrewarmList.Identity(item.Record));
+                        if (Interlocked.Increment(ref _shaderPrewarmProgress) % PrewarmProgressBatch == 0)
+                        {
+                            FlushShaderPrewarmProgress(list, stamp);
+                        }
                     }
 
+                    FlushShaderPrewarmProgress(list, stamp);
                     if (Interlocked.Decrement(ref remaining) == 0)
                     {
                         FinishShaderPrewarm(list, stamp, started);
@@ -99,6 +128,19 @@ internal static unsafe partial class VulkanVideoPresenter
                 };
                 _shaderPrewarmThreads[index].Start();
             }
+
+            return true;
+        }
+
+        private void FlushShaderPrewarmProgress(ShaderPrewarmList list, string stamp)
+        {
+            var batch = new List<ulong>();
+            while (_shaderPrewarmCompleted.TryDequeue(out var identity))
+            {
+                batch.Add(identity);
+            }
+
+            list.AppendProgress(stamp, batch);
         }
 
         private static string ShaderPrewarmStampPart(Type type) =>
@@ -109,8 +151,7 @@ internal static unsafe partial class VulkanVideoPresenter
                 '|',
                 ShaderPrewarmStampPart(typeof(Gen5ShaderTranslator)),
                 ShaderPrewarmStampPart(typeof(Gen5SpirvTranslator)),
-                ShaderPrewarmStampPart(compiler.GetType()),
+                compiler.GetType().FullName,
-                ShaderPrewarmStampPart(typeof(ShaderProgramCache)),
                 DriverCacheSignature().TrimEnd('\n'));
 
         private void PrewarmComputePipeline(
@@ -182,11 +223,14 @@ internal static unsafe partial class VulkanVideoPresenter
             var matched = runtime.Keys.Count(prewarmed.ContainsKey);
             if (_shaderPrewarmStopping)
             {
+                SetShaderPrewarmState(false);
                 return;
             }
 
             list.WriteStamp(stamp);
+            list.ClearProgress();
             _shaderPrewarmFinished = true;
+            SetShaderPrewarmState(false);
             _pipelineCacheDirty = true;
             Console.Error.WriteLine(
                 $"[LOADER][INFO] Shader prewarm done: compiled={Volatile.Read(ref _shaderPrewarmCompiled)} " +
@@ -218,6 +262,7 @@ internal static unsafe partial class VulkanVideoPresenter
         private void StopShaderPrewarm()
         {
             _shaderPrewarmStopping = true;
+            SetShaderPrewarmState(false);
             foreach (var thread in _shaderPrewarmThreads)
             {
                 thread.Join(TimeSpan.FromSeconds(10));

src/SharpEmu.ShaderCompiler/Resources/ResourceMaterializer.cs

@@ -473,6 +473,19 @@ public static class ResourceMaterializer
         return value.ToString();
     }
 
+    private static readonly HashSet<uint> NulledSampledFormats = new();
+
+    private static void ReportNulledSampledFormat(uint format)
+    {
+        lock (NulledSampledFormats)
+        {
+            if (NulledSampledFormats.Add(format))
+            {
+                Console.Error.WriteLine($"[GPU][WARN] A sampled image descriptor uses unsupported format {format}; it is bound as a null texture.");
+            }
+        }
+    }
+
     private static bool NullImageDescriptor(ReadOnlySpan<uint> descriptor) =>
         descriptor[0] == 0 && (descriptor[1] & 0xFF) == 0;
 
@@ -1054,7 +1067,19 @@ public static class ResourceMaterializer
                     numericClass = ImageNumericClass.Uint;
                 }
             }
-            else if (numericClass == ImageNumericClass.Unsupported || (baseImage.DepthCompare && numericClass != ImageNumericClass.Float))
+            else if (numericClass == ImageNumericClass.Unsupported)
+            {
+                ReportNulledSampledFormat(format);
+                Array.Clear(descriptor);
+                images[index] = image with
+                {
+                    NumericClass = ImageNumericClass.Float,
+                    Dimension = ImageDimension.Dim2D,
+                    Cube = false,
+                };
+                continue;
+            }
+            else if (baseImage.DepthCompare && numericClass != ImageNumericClass.Float)
             {
                 return Fail($"sampled image descriptor {index} uses unsupported format {format}");
             }

tests/SharpEmu.Libs.Tests/Audio/Atrac9GaplessTests.cs

@@ -0,0 +1,113 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Libs.Audio;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Audio;
+
+public sealed class Atrac9GaplessTests
+{
+    private static readonly byte[] MonoConfig = [0xFE, 0x70, 0x17, 0xE0];
+    private const int SuperframeBytes = 192;
+    private const int SuperframeSamples = 256;
+    private static readonly byte[] SilentFrame = [0x00, 0x84, 0x00, 0x40];
+
+    private static Atrac9DecodeState CreateDecoder()
+    {
+        var decoder = new Atrac9DecodeState();
+        Assert.True(decoder.TryInitialize(MonoConfig));
+        return decoder;
+    }
+
+    private static Atrac9DecodeResult DecodeSuperframes(Atrac9DecodeState decoder, int superframes, int outputSamples)
+    {
+        var input = new byte[SuperframeBytes * superframes];
+        for (var superframe = 0; superframe < superframes; superframe++)
+        {
+            SilentFrame.CopyTo(input, superframe * SuperframeBytes);
+        }
+
+        var output = new byte[outputSamples * sizeof(short)];
+        return decoder.Decode(input, output, Atrac9PcmEncoding.Signed16, requestedChannels: 0, multipleFrames: true);
+    }
+
+    [Fact]
+    public void WithoutAWindowEverySuperframeSampleIsWritten()
+    {
+        var decoder = CreateDecoder();
+
+        var result = DecodeSuperframes(decoder, 2, SuperframeSamples * 2);
+
+        Assert.Equal(SuperframeSamples * 2 * sizeof(short), result.OutputWritten);
+        Assert.Equal((ulong)(SuperframeSamples * 2), result.TotalDecodedSamples);
+        Assert.Equal(default, decoder.Gapless);
+    }
+
+    [Fact]
+    public void TheWindowSkipsTheLeadInAndStopsAtTheTotal()
+    {
+        var decoder = CreateDecoder();
+        decoder.SetGapless(totalSamples: 500, skipSamples: 100, reset: false);
+
+        var first = DecodeSuperframes(decoder, 1, SuperframeSamples);
+        Assert.Equal(156 * sizeof(short), first.OutputWritten);
+        Assert.Equal(new Atrac9Gapless(344, 0, 100), decoder.Gapless);
+
+        var rest = DecodeSuperframes(decoder, 3, SuperframeSamples * 3);
+        Assert.Equal((256 + 88) * sizeof(short), rest.OutputWritten);
+        Assert.Equal(SuperframeBytes * 2, rest.InputConsumed);
+        Assert.Equal(new Atrac9Gapless(0, 0, 100 + 256 - 88), decoder.Gapless);
+        Assert.Equal(500ul, rest.TotalDecodedSamples);
+
+        var ended = DecodeSuperframes(decoder, 1, SuperframeSamples);
+        Assert.Equal(0, ended.OutputWritten);
+        Assert.Equal(0, ended.InputConsumed);
+    }
+
+    [Fact]
+    public void ALeadInLongerThanASuperframeWritesNothingForIt()
+    {
+        var decoder = CreateDecoder();
+        decoder.SetGapless(totalSamples: 0, skipSamples: 300, reset: false);
+
+        var first = DecodeSuperframes(decoder, 1, 0);
+        Assert.Equal(0, first.OutputWritten);
+        Assert.Equal(SuperframeBytes, first.InputConsumed);
+        Assert.Equal(new Atrac9Gapless(0, 44, 256), decoder.Gapless);
+
+        var second = DecodeSuperframes(decoder, 1, SuperframeSamples);
+        Assert.Equal((256 - 44) * sizeof(short), second.OutputWritten);
+        Assert.Equal(new Atrac9Gapless(0, 0, 300), decoder.Gapless);
+    }
+
+    [Fact]
+    public void TheRoomCheckUsesTheTrimmedSize()
+    {
+        var decoder = CreateDecoder();
+        decoder.SetGapless(totalSamples: 100, skipSamples: 0, reset: false);
+
+        var result = DecodeSuperframes(decoder, 1, 100);
+
+        Assert.Equal(100 * sizeof(short), result.OutputWritten);
+        Assert.Equal(0, result.Status & Atrac9DecodeState.ResultNotEnoughRoom);
+    }
+
+    [Fact]
+    public void ResetRestoresTheWindowAndASetWithoutResetKeepsProgress()
+    {
+        var decoder = CreateDecoder();
+        decoder.SetGapless(totalSamples: 500, skipSamples: 100, reset: false);
+        DecodeSuperframes(decoder, 1, SuperframeSamples);
+
+        decoder.SetGapless(totalSamples: 500, skipSamples: 100, reset: false);
+        Assert.Equal(new Atrac9Gapless(344, 0, 100), decoder.Gapless);
+
+        decoder.Reset();
+        Assert.Equal(new Atrac9Gapless(500, 100, 0), decoder.Gapless);
+
+        DecodeSuperframes(decoder, 1, SuperframeSamples);
+        decoder.SetGapless(totalSamples: 2000, skipSamples: 10, reset: true);
+        Assert.Equal(new Atrac9Gapless(2000, 10, 0), decoder.Gapless);
+    }
+}

tests/SharpEmu.Libs.Tests/Audio/AudioOut2MixTests.cs

@@ -0,0 +1,158 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Buffers.Binary;
+using SharpEmu.HLE;
+using SharpEmu.Libs.Audio;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Audio;
+
+public sealed class AudioOut2MixTests
+{
+    private const ulong MemoryBase = 0x1_0000_0000;
+    private const ushort ObjectMain = 0x100;
+    private const float HalfPower = 0.70710677f;
+
+    [Theory]
+    [InlineData((ushort)0, true)]
+    [InlineData((ushort)1, true)]
+    [InlineData((ushort)2, true)]
+    [InlineData(ObjectMain, true)]
+    [InlineData((ushort)3, false)]
+    [InlineData((ushort)4, false)]
+    [InlineData((ushort)5, false)]
+    [InlineData((ushort)6, false)]
+    public void OnlyMainBgmAndVoicePortsReachTheSpeakers(ushort portType, bool expected)
+    {
+        Assert.Equal(expected, AudioOut2Exports.RoutesToSpeakers(portType));
+        Assert.Equal(expected, AudioOut2Exports.TryGetStereoGains(portType, 2, 1f, AudioOut2Exports.AmbisonicsNone, 0, out _, out _));
+    }
+
+    [Theory]
+    [InlineData(64u, HalfPower, HalfPower)]
+    [InlineData(65u, HalfPower, -HalfPower)]
+    [InlineData(0u, 1f, 1f)]
+    [InlineData(2u, HalfPower, -HalfPower)]
+    public void FirstOrderAmbisonicsDecodeToStereoCardioids(uint ambisonics, float left, float right)
+    {
+        Assert.True(AudioOut2Exports.TryGetStereoGains(ObjectMain, 1, 0.5f, ambisonics, 0, out var leftGain, out var rightGain));
+        Assert.Equal(left * 0.5f, leftGain, 5);
+        Assert.Equal(right * 0.5f, rightGain, 5);
+    }
+
+    [Theory]
+    [InlineData(66u)]
+    [InlineData(67u)]
+    [InlineData(99u)]
+    [InlineData(1u)]
+    [InlineData(3u)]
+    [InlineData(15u)]
+    public void HigherAmbisonicComponentsDoNotFeedStereo(uint ambisonics)
+    {
+        Assert.False(AudioOut2Exports.TryGetStereoGains(ObjectMain, 1, 1f, ambisonics, 0, out _, out _));
+    }
+
+    [Fact]
+    public void PlainObjectsPlayCentredOrPassThroughToOneSide()
+    {
+        Assert.True(AudioOut2Exports.TryGetStereoGains(ObjectMain, 1, 1f, AudioOut2Exports.AmbisonicsNone, 0, out var left, out var right));
+        Assert.Equal(HalfPower, left, 5);
+        Assert.Equal(HalfPower, right, 5);
+        Assert.True(AudioOut2Exports.TryGetStereoGains(ObjectMain, 1, 1f, AudioOut2Exports.AmbisonicsNone, AudioOut2Exports.PassthroughLeft, out left, out right));
+        Assert.Equal((1f, 0f), (left, right));
+        Assert.True(AudioOut2Exports.TryGetStereoGains(ObjectMain, 1, 1f, AudioOut2Exports.AmbisonicsNone, AudioOut2Exports.PassthroughRight, out left, out right));
+        Assert.Equal((0f, 1f), (left, right));
+        Assert.False(AudioOut2Exports.TryGetStereoGains(ObjectMain, 1, 0f, AudioOut2Exports.AmbisonicsNone, 0, out _, out _));
+    }
+
+    [Fact]
+    public void FifthOrderSceneDecodesASourceToItsSide()
+    {
+        const int frames = 4;
+        var leftSource = DecodeScene(frames, azimuthSine: 1f);
+        var centreSource = DecodeScene(frames, azimuthSine: 0f);
+
+        Assert.Equal(2f * HalfPower, leftSource[0], 4);
+        Assert.Equal(0f, leftSource[1], 4);
+        Assert.Equal(HalfPower, centreSource[0], 4);
+        Assert.Equal(HalfPower, centreSource[1], 4);
+    }
+
+    [Fact]
+    public void SetAttributesStoresGainAmbisonicsAndPassthrough()
+    {
+        var memory = new FakeCpuMemory(MemoryBase, 0x1000);
+        var ctx = new CpuContext(memory, Generation.Gen5);
+        var param = new byte[0x40];
+        BinaryPrimitives.WriteUInt16LittleEndian(param, ObjectMain);
+        BinaryPrimitives.WriteUInt32LittleEndian(param.AsSpan(4), 0x100);
+        Assert.True(memory.TryWrite(MemoryBase, param));
+        ctx[CpuRegister.Rdi] = 0;
+        ctx[CpuRegister.Rsi] = MemoryBase;
+        ctx[CpuRegister.Rdx] = MemoryBase + 0x80;
+        Assert.Equal(0, AudioOut2Exports.AudioOut2PortCreate(ctx));
+        var handle = BinaryPrimitives.ReadUInt64LittleEndian(Read(memory, MemoryBase + 0x80, 8));
+
+        var values = new byte[12];
+        BinaryPrimitives.WriteSingleLittleEndian(values, 0.25f);
+        BinaryPrimitives.WriteUInt32LittleEndian(values.AsSpan(4), 65);
+        BinaryPrimitives.WriteUInt32LittleEndian(values.AsSpan(8), AudioOut2Exports.PassthroughLeft);
+        Assert.True(memory.TryWrite(MemoryBase + 0x100, values));
+        var attributes = new byte[0x18 * 3];
+        WriteAttribute(attributes, 0, 1, MemoryBase + 0x100);
+        WriteAttribute(attributes, 1, 8, MemoryBase + 0x104);
+        WriteAttribute(attributes, 2, 5, MemoryBase + 0x108);
+        Assert.True(memory.TryWrite(MemoryBase + 0x200, attributes));
+        ctx[CpuRegister.Rdi] = handle;
+        ctx[CpuRegister.Rsi] = MemoryBase + 0x200;
+        ctx[CpuRegister.Rdx] = 3;
+
+        Assert.Equal(0, AudioOut2Exports.AudioOut2PortSetAttributes(ctx));
+
+        Assert.Equal((0.25f, 65u, AudioOut2Exports.PassthroughLeft), AudioOut2Exports.PortMixAttributes(handle));
+        ctx[CpuRegister.Rdi] = handle;
+        AudioOut2Exports.AudioOut2PortDestroy(ctx);
+    }
+
+    private static float[] DecodeScene(int frames, float azimuthSine)
+    {
+        var mix = new float[frames * 2];
+        var source = new byte[frames * sizeof(float)];
+        for (var acn = 0u; acn < 36; acn++)
+        {
+            var component = acn switch
+            {
+                0 => 1f,
+                1 => azimuthSine,
+                _ => 0.6f,
+            };
+            for (var frame = 0; frame < frames; frame++)
+            {
+                BinaryPrimitives.WriteSingleLittleEndian(source.AsSpan(frame * sizeof(float)), component);
+            }
+
+            if (AudioOut2Exports.TryGetStereoGains(ObjectMain, 1, 1f, AudioOut2Exports.AmbisonicsAcnBase + acn, 0, out var left, out var right))
+            {
+                AudioOut2Exports.MixPortIntoStereo(source, mix, frames, 1, sizeof(float), true, left, right);
+            }
+        }
+
+        return mix;
+    }
+
+    private static void WriteAttribute(byte[] attributes, int index, uint id, ulong value)
+    {
+        var entry = attributes.AsSpan(index * 0x18, 0x18);
+        BinaryPrimitives.WriteUInt32LittleEndian(entry, id);
+        BinaryPrimitives.WriteUInt64LittleEndian(entry[0x08..], value);
+        BinaryPrimitives.WriteUInt64LittleEndian(entry[0x10..], sizeof(uint));
+    }
+
+    private static byte[] Read(FakeCpuMemory memory, ulong address, int length)
+    {
+        var bytes = new byte[length];
+        Assert.True(memory.TryRead(address, bytes));
+        return bytes;
+    }
+}

tests/SharpEmu.Libs.Tests/Audio/AudioOut2PacingTests.cs

@@ -0,0 +1,28 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Libs.Audio;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.Audio;
+
+public sealed class AudioOut2PacingTests
+{
+    [Theory]
+    [InlineData(256u, 48000u, 1u, 40.0)]
+    [InlineData(256u, 48000u, 2u, 45.333)]
+    [InlineData(256u, 48000u, 4u, 56.0)]
+    [InlineData(1024u, 48000u, 4u, 104.0)]
+    public void ABlockingPushWaitsUntilTheDeviceHoldsTheCushionAndOneSlotLessThanTheQueue(
+        uint grainSamples, uint frequency, uint queueDepth, double expected)
+    {
+        Assert.Equal(expected, AudioOut2Exports.DeviceSlotFreeThreshold(grainSamples, frequency, queueDepth), 3);
+    }
+
+    [Fact]
+    public void TheThresholdStaysFarBelowTheHostQueueCap()
+    {
+        const double hostCapMilliseconds = 128 * 1024 * 1000.0 / (48000 * 4);
+        Assert.True(AudioOut2Exports.DeviceSlotFreeThreshold(256, 48000, 2) < hostCapMilliseconds / 10);
+    }
+}

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

@@ -0,0 +1,44 @@
+// 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 GuestStackBoundsTests
+{
+    [Fact]
+    public unsafe void AllocationQueryHandlesProtectionSplitsAndFallsBackForPartialCommit()
+    {
+        if (!OperatingSystem.IsWindows()) return;
+
+        var pageSize = (nuint)Environment.SystemPageSize;
+        var memory = (byte*)HostMemory.Alloc(null, pageSize * 3,
+            HostMemory.MEM_RESERVE | HostMemory.MEM_COMMIT, HostMemory.PAGE_READWRITE);
+        Assert.True(memory != null);
+        try
+        {
+            Assert.True(HostMemory.Protect(memory + pageSize, pageSize, HostMemory.PAGE_READONLY, out _));
+            // VirtualQuery at the last page would return only that page, not the allocation.
+            Assert.True(DirectExecutionBackend.TryGetGuestStackBounds((ulong)(memory + pageSize * 2 + 16),
+                out var bottom, out var top));
+            Assert.Equal((ulong)memory, bottom);
+            Assert.Equal((ulong)(memory + pageSize * 3), top);
+
+            Assert.True(HostMemory.Free(memory, pageSize, 0x4000)); // MEM_DECOMMIT
+            Assert.True(DirectExecutionBackend.TryGetGuestStackBounds((ulong)(memory + pageSize * 2 + 16),
+                out bottom, out top));
+            Assert.Equal((ulong)(memory + pageSize * 2), bottom);
+            Assert.Equal((ulong)(memory + pageSize * 3), top);
+            Assert.False(DirectExecutionBackend.TryGetGuestStackBounds((ulong)memory, out _, out _));
+        }
+        finally
+        {
+            Assert.True(HostMemory.Free(memory, 0, HostMemory.MEM_RELEASE));
+        }
+
+        Assert.False(DirectExecutionBackend.TryGetGuestStackBounds(0, out _, out _));
+    }
+}

tests/SharpEmu.Libs.Tests/Gpu/Buffers/GuestBufferCacheTests.cs

@@ -104,6 +104,43 @@ public sealed class GuestBufferCacheTests : IClassFixture<HeadlessVulkanFixture>
         Assert.Equal(new byte[] { 0x78, 0x56, 0x34, 0x12 }, harness.Read(address, 4));
     }
 
+    [Fact]
+    public void AHostWordCopyRepeatsTheSourceAndReachesARegisteredBuffer()
+    {
+        if (_vulkan is null) return;
+        using var harness = new CacheHarness(_vulkan);
+        var address = harness.MapBacked(Page, ReadWrite);
+        var destination = address + 0x100;
+        harness.Write(address, Bytes(1u, 2u, 3u));
+        var (before, beforeOffset) = harness.Worker.Run(() => harness.Cache.ObtainBuffer(destination, 28, isWritten: false));
+        Assert.Equal(new byte[28], harness.ReadBack(before, beforeOffset, 28));
+
+        Assert.True(harness.Worker.Run(() => harness.Cache.TryCopyWordsOnHost(destination, address, 3, 7)));
+
+        var expected = Bytes(1u, 2u, 3u, 1u, 2u, 3u, 1u);
+        Assert.Equal(expected, harness.Read(destination, 28));
+        Assert.False(harness.Cache.HasGpuDirtyBytes(destination, 28));
+        var (buffer, offset) = harness.Worker.Run(() => harness.Cache.ObtainBuffer(destination, 28, isWritten: false));
+        Assert.Equal(expected, harness.ReadBack(buffer, offset, 28));
+        harness.Shutdown();
+    }
+
+    [Fact]
+    public void AHostWordCopyIsRefusedForGpuWrittenOrOverlappingRanges()
+    {
+        if (_vulkan is null) return;
+        using var harness = new CacheHarness(_vulkan);
+        var address = harness.MapBacked(Page, ReadWrite);
+        harness.Write(address, Bytes(1u, 2u, 3u, 4u));
+
+        Assert.False(harness.Worker.Run(() => harness.Cache.TryCopyWordsOnHost(address + 8, address, 4, 4)));
+        harness.Worker.Run(() => harness.Cache.ObtainBuffer(address + 0x200, 4, isWritten: true));
+        Assert.False(harness.Worker.Run(() => harness.Cache.TryCopyWordsOnHost(address + 0x100, address + 0x200, 1, 1)));
+        Assert.False(harness.Worker.Run(() => harness.Cache.TryCopyWordsOnHost(address + 0x200, address, 1, 1)));
+        Assert.True(harness.Worker.Run(() => harness.Cache.TryCopyWordsOnHost(address + 0x100, address, 4, 4)));
+        harness.Shutdown();
+    }
+
     [Theory]
     [InlineData(false)]
     [InlineData(true)]

tests/SharpEmu.Libs.Tests/Gpu/Pipelines/BoundedFillDetectorTests.cs

@@ -127,6 +127,48 @@ public sealed class BoundedFillDetectorTests
         Assert.True(fill.Formatted);
     }
 
+    private static readonly uint[] DemonsSoulsModuloCopy =
+    [
+        0xBEFC03FF, 0xA65CD91E, 0xBF960000, 0xBFA00003, 0xD7460002, 0x04010C0C, 0xF4201A84, 0xFA000000,
+        0xBF8CC07F, 0x7DA8046A, 0xBF88002A, 0xF4200304, 0xFA000004, 0xBF8CC07F, 0x7E000C0C, 0xBF070C80,
+        0x8588807E, 0x7E005700, 0x100000FF, 0x4F800000, 0x7E060F00, 0xD5766A00, 0x0202060C, 0x7D8A0280,
+        0x4C020080, 0x02000101, 0xD56A0001, 0x00020700, 0x4C000303, 0x4A020303, 0x02000101, 0xD56A0000,
+        0x00020500, 0xD5690001, 0x0002000C, 0x4C060302, 0x7D8C02F9, 0x06068A02, 0x7D86060C, 0x87EA6A0A,
+        0x50000080, 0xD5286A00, 0x002A00C1, 0xD5010000, 0x002200C1, 0xD5690000, 0x0002000C, 0x4C000102,
+        0xE0002000, 0x80000000, 0xBF8C3F70, 0xE0102000, 0x80010002, 0xBF810000,
+    ];
+
+    [Fact]
+    public void TheDemonsSoulsModuloCopyIsRecognized()
+    {
+        var program = Decode(DemonsSoulsModuloCopy);
+        var copy = BoundedFillDetector.DetectCopy(program);
+
+        Assert.NotNull(copy);
+        static FillWord User(uint register) => new(FillWordSource.UserData, register, 0, 0);
+        Assert.Equal(12u, copy.GroupScalarRegister);
+        Assert.Equal(new FillWord(FillWordSource.BufferResource, 8, 0, 0), copy.Count);
+        Assert.Equal(new FillWord(FillWordSource.BufferResource, 8, 0, 4), copy.Modulus);
+        Assert.Equal([User(0), User(1), User(2), User(3)], copy.Source);
+        Assert.Equal([User(4), User(5), User(6), User(7)], copy.Destination);
+        Assert.Null(BoundedFillDetector.Detect(program));
+    }
+
+    [Fact]
+    public void AModuloCopyStoringAtTheRemainderIsRejected()
+    {
+        var words = DemonsSoulsModuloCopy.ToArray();
+        words[Array.IndexOf(words, 0x80010002u)] = 0x80010000u;
+        Assert.Null(BoundedFillDetector.DetectCopy(Decode(words)));
+    }
+
+    [Fact]
+    public void FillsAreNotCopies()
+    {
+        Assert.Null(BoundedFillDetector.DetectCopy(Decode(PatternFromUserData)));
+        Assert.Null(BoundedFillDetector.DetectCopy(Decode(ZeroRangeFromConstantBuffer)));
+    }
+
     [Fact]
     public void APatternFillWithAnotherBranchTargetIsRejected()
     {

tests/SharpEmu.Libs.Tests/Gpu/Pipelines/ShaderPrewarmListTests.cs

@@ -119,6 +119,52 @@ public sealed class ShaderPrewarmListTests : IDisposable
         Assert.False(list.IsStampCurrent("build-b"));
     }
 
+    [Fact]
+    public void ProgressResumesUnderTheSameStampAndClears()
+    {
+        using (var list = Open())
+        {
+            Assert.Empty(list.ReadProgress("build-a"));
+            list.AppendProgress("build-a", [1UL, 2UL]);
+            list.AppendProgress("build-a", [0xFEDC_BA98_7654_3210UL]);
+        }
+
+        using (var reopened = Open())
+        {
+            Assert.Equal(new HashSet<ulong> { 1UL, 2UL, 0xFEDC_BA98_7654_3210UL }, reopened.ReadProgress("build-a"));
+            reopened.ClearProgress();
+            Assert.Empty(reopened.ReadProgress("build-a"));
+        }
+    }
+
+    [Fact]
+    public void ProgressOfAnotherStampIsDiscarded()
+    {
+        using var list = Open();
+        list.AppendProgress("build-a", [7UL]);
+
+        Assert.Empty(list.ReadProgress("build-b"));
+        Assert.Empty(list.ReadProgress("build-a"));
+        list.AppendProgress("build-b", [8UL]);
+        Assert.Equal(new HashSet<ulong> { 8UL }, list.ReadProgress("build-b"));
+    }
+
+    [Fact]
+    public void ARecordIdentityDependsOnItsSpecialization()
+    {
+        using (var list = Open())
+        {
+            _ = CompileAtRuntime(list, BufferDescriptorWords.Format32UInt);
+            _ = CompileAtRuntime(list, BufferDescriptorWords.Format32x4UInt);
+        }
+
+        using var reloaded = Open();
+        var identities = reloaded.LoadedComputes().Select(item => ShaderPrewarmList.Identity(item.Record)).ToArray();
+        Assert.Equal(2, identities.Length);
+        Assert.NotEqual(identities[0], identities[1]);
+        Assert.Equal(identities[0], ShaderPrewarmList.Identity(reloaded.LoadedComputes()[0].Record));
+    }
+
     [Fact]
     public void RecordedReadsReplayAsMergedRanges()
     {

tests/SharpEmu.Libs.Tests/Gpu/Rendering/RenderExecutorComputeTests.cs

@@ -416,6 +416,83 @@ public sealed class RenderExecutorComputeTests : IDisposable
         AssertNotDispatched();
     }
 
+    private const ulong CopySource = RecordingRenderHost.MemoryBase + 0x71_0000;
+
+    private void ConfigureBoundedCopy(uint count, uint modulus, uint sourceRecords, uint destinationRecords, uint sourceFormat = Format32UInt)
+    {
+        static SharpEmu.Libs.Gpu.Pipelines.FillWord User(uint register) =>
+            new(SharpEmu.Libs.Gpu.Pipelines.FillWordSource.UserData, register, 0, 0);
+        _host.WriteGuest(FillParameters, [.. BitConverter.GetBytes(count), .. BitConverter.GetBytes(modulus)]);
+        var copy = new SharpEmu.Libs.Gpu.Pipelines.BoundedCopy(
+            12,
+            new SharpEmu.Libs.Gpu.Pipelines.FillWord(SharpEmu.Libs.Gpu.Pipelines.FillWordSource.BufferResource, 8, 0, 0),
+            new SharpEmu.Libs.Gpu.Pipelines.FillWord(SharpEmu.Libs.Gpu.Pipelines.FillWordSource.BufferResource, 8, 0, 4),
+            [User(0), User(1), User(2), User(3)],
+            [User(4), User(5), User(6), User(7)]);
+        var program = new ShaderProgramInfo { Stage = ShaderStageKind.Compute, Hash = 0xF333, BoundedCopy = copy };
+        var source = BufferDescriptor(CopySource, 4, sourceRecords, format: sourceFormat);
+        var destination = BufferDescriptor(MetadataAddress, 4, destinationRecords, format: Format32UInt);
+        var parameters = BufferDescriptor(FillParameters, 16, 1, format: 0);
+        var input = ComputeProgram(Stage(program, userData: [.. source, .. destination, .. parameters])).Input;
+        _pipelines.Compute = new ComputeProgram
+        {
+            Program = new ShaderProgram(0x33),
+            Input = new ComputeInputInfo
+            {
+                ThreadsX = 64, ThreadsY = 1, ThreadsZ = 1, GroupIdX = true, ThreadIdCount = 1, WaveSize = 64,
+                WorkgroupRegister = 12, Stage = input.Stage,
+            },
+        };
+    }
+
+    [Fact]
+    public void BoundedCopy_BecomesAHostCopyAndRecordsNothing()
+    {
+        ConfigureBoundedCopy(count: 0x98, modulus: 0x98, sourceRecords: 0x98, destinationRecords: 0x98);
+        _executor.Dispatch(1, Banks(), 3, 1, 1, 0x41);
+
+        Assert.Contains($"host_copy {MetadataAddress:X} {CopySource:X} 152 152", _host.Calls);
+        AssertNotDispatched();
+        Assert.Contains("reset_bindings", _host.Calls);
+    }
+
+    [Fact]
+    public void BoundedCopy_IsClampedToTheThreadsAndTheDestinationRecords()
+    {
+        ConfigureBoundedCopy(count: 0x1000, modulus: 4, sourceRecords: 4, destinationRecords: 0x400);
+        _executor.Dispatch(1, Banks(), 4, 1, 1, 0x41);
+        Assert.Contains($"host_copy {MetadataAddress:X} {CopySource:X} 4 256", _host.Calls);
+
+        ConfigureBoundedCopy(count: 0x1000, modulus: 4, sourceRecords: 4, destinationRecords: 0x20);
+        _executor.Dispatch(1, Banks(), 4, 1, 1, 0x41);
+        Assert.Contains($"host_copy {MetadataAddress:X} {CopySource:X} 4 32", _host.Calls);
+        AssertNotDispatched();
+    }
+
+    [Theory]
+    [InlineData(0u, 4u, Format32UInt)]
+    [InlineData(8u, 4u, Format32UInt)]
+    [InlineData(4u, 4u, 22u)]
+    public void BoundedCopyThatIsNotAPlainWordCopy_IsDispatched(uint modulus, uint sourceRecords, uint sourceFormat)
+    {
+        ConfigureBoundedCopy(count: 0x40, modulus: modulus, sourceRecords: sourceRecords, destinationRecords: 0x40, sourceFormat: sourceFormat);
+        _executor.Dispatch(1, Banks(), 1, 1, 1, 0x41);
+
+        Assert.DoesNotContain(_host.Calls, call => call.StartsWith("host_copy", StringComparison.Ordinal));
+        AssertDispatched(1, 1, 1);
+    }
+
+    [Fact]
+    public void BoundedCopyTheHostRefuses_IsDispatched()
+    {
+        _host.HostCopyAccepted = false;
+        ConfigureBoundedCopy(count: 0x40, modulus: 0x40, sourceRecords: 0x40, destinationRecords: 0x40);
+        _executor.Dispatch(1, Banks(), 1, 1, 1, 0x41);
+
+        Assert.Contains($"host_copy {MetadataAddress:X} {CopySource:X} 64 64", _host.Calls);
+        AssertDispatched(1, 1, 1);
+    }
+
     private void ConfigurePatternFill(uint count, uint length, uint[] pattern)
     {
         static SharpEmu.Libs.Gpu.Pipelines.FillWord User(uint register) =>

tests/SharpEmu.Libs.Tests/Gpu/Rendering/RenderExecutorTestSupport.cs

@@ -394,6 +394,14 @@ internal sealed class RecordingRenderHost : IRenderHost
         return RegisteredDcc.Contains(address);
     }
 
+    public bool HostCopyAccepted { get; set; } = true;
+
+    public bool TryCopyWordsOnHost(ulong destination, ulong source, ulong sourceWords, ulong words)
+    {
+        Calls.Add($"host_copy {destination:X} {source:X} {sourceWords} {words}");
+        return HostCopyAccepted;
+    }
+
     public Exception Fatal(string message) => new RenderExecutorFatalException(message);
 }
 

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

@@ -30,6 +30,10 @@ public sealed class PresenterStartupTests
             Set("_presenterStartupFailure", null);
             Set("_activePresenter", null);
             Set("_thread", Thread.CurrentThread);
+            Set("_shaderPrewarmDecided", true);
+            Set("_shaderPrewarmRunning", false);
+            Set("_shaderPrewarmReleased", false);
+            Set("_shaderPrewarmHoldReported", 0);
         }
 
         private static FieldInfo Field(string name) => PresenterType.GetField(name, BindingFlags.Static | BindingFlags.NonPublic)!;
@@ -106,6 +110,45 @@ public sealed class PresenterStartupTests
         }
     }
 
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public void ASubmissionWaitsUntilTheShaderPrewarmIsDecidedAndDone(bool undecided)
+    {
+        var runner = new StreamRunner();
+        var queue = new CommandStreamQueue(runner.Host);
+        Assert.True(runner.Host.Memory.TryWrite(StreamRunner.CommandAddress, new byte[] { 0, 16, 0, 192, 0, 0, 0, 0 }));
+        using var state = new StartupState();
+        state.Set(undecided ? "_shaderPrewarmDecided" : "_shaderPrewarmRunning", !undecided);
+        state.Publish(queue);
+        Exception? failure = null;
+        var thread = new Thread(() =>
+        {
+            try { VulkanVideoPresenter.SubmitCommandStream(runner.Host.Memory, 0, StreamRunner.CommandAddress, 2, 1, null); }
+            catch (Exception exception) { failure = exception; }
+        });
+        thread.Start();
+        try
+        {
+            Assert.True(SpinWait.SpinUntil(() => (thread.ThreadState & ThreadState.WaitSleepJoin) != 0, 5000));
+            Assert.False(thread.Join(200));
+            Assert.Equal(0, queue.PendingSubmissionCount);
+            state.Set("_shaderPrewarmDecided", true);
+            state.Set("_shaderPrewarmRunning", false);
+            Assert.True(thread.Join(5000));
+            Assert.Null(failure);
+            Assert.Equal(1, queue.PendingSubmissionCount);
+        }
+        finally
+        {
+            if (thread.IsAlive)
+            {
+                VulkanVideoPresenter.RequestClose();
+                Assert.True(thread.Join(5000));
+            }
+        }
+    }
+
     [Fact]
     public void StartupFailureRejectsTheSubmission()
     {