Support mountable-content DLC (addcont with real content) (#1581)

Support mountable-content DLC (addcont) and fix PlayGo chunk count query

CMakeLists.txt

@@ -350,7 +350,7 @@ set(inc_headers
 	${KYTY_THIRD_PARTY_DIR}/SPIRV-Tools/include
 	${KYTY_THIRD_PARTY_DIR}/SPIRV-Headers/include
 	${KYTY_THIRD_PARTY_DIR}/fmt/include
-	${KYTY_THIRD_PARTY_DIR}/xxhash
+	${KYTY_THIRD_PARTY_DIR}/xxHash
 	${KYTY_THIRD_PARTY_DIR}/cpuinfo/include
 	${KYTY_THIRD_PARTY_DIR}/renderdoc
 	${KYTY_THIRD_PARTY_DIR}/stb

src/graphics/shader/recompiler/backend/spirv/spirvEmitterInstructions.h

@@ -326,6 +326,7 @@ inline constexpr auto EmitSharedAtomicSMin32    = EmitAtomic32;
 inline constexpr auto EmitSharedAtomicUMin32    = EmitAtomic32;
 inline constexpr auto EmitSharedAtomicSMax32    = EmitAtomic32;
 inline constexpr auto EmitSharedAtomicUMax64    = EmitSharedAtomic64;
+inline constexpr auto EmitSharedAtomicCmpSwap32 = EmitAtomic32;
 inline constexpr auto EmitSharedAtomicCmpSwap64 = EmitSharedAtomic64;
 inline constexpr auto EmitSharedAtomicUMax32    = EmitAtomic32;
 inline constexpr auto EmitSharedAtomicAnd32     = EmitAtomic32;

src/graphics/shader/recompiler/backend/spirv/spirvEmitterMemoryHelpers.cpp

@@ -504,6 +504,7 @@ uint32_t EncodePackedColorComponent(EmitterState& state, const Format::BufferFor
 
 spv::Op SpirvAtomicOpcode(IR::ValueOpcode opcode) {
 	switch (opcode) {
+		case IR::ValueOpcode::SharedAtomicCmpSwap32:
 		case IR::ValueOpcode::SharedAtomicCmpSwap64:
 		case IR::ValueOpcode::ImageAtomicCompareSwap32:
 		case IR::ValueOpcode::BufferAtomicCmpSwap32: return spv::OpAtomicCompareExchange;
@@ -561,8 +562,12 @@ uint32_t EmitAtomicOperation(ValueEmitContext& ctx, const IR::Inst& inst, uint32
 	const bool wide   = inst.GetType() == IR::Type::U64;
 	const auto type   = wide ? TypeU64(ctx.state) : TypeU32(ctx.state);
 	if (opcode == spv::OpAtomicCompareExchange) {
-		const auto desired    = ctx.Arg(inst, inst.NumArgs() - 3);
-		const auto comparator = ctx.Arg(inst, inst.NumArgs() - 2);
+		auto desired    = ctx.Arg(inst, inst.NumArgs() - 3);
+		auto comparator = ctx.Arg(inst, inst.NumArgs() - 2);
+		if (inst.GetOpcode() == IR::ValueOpcode::SharedAtomicCmpSwap32) {
+			// RDNA2 DS compares DATA and stores DATA2, opposite to BUFFER atomics.
+			std::swap(desired, comparator);
+		}
 		ctx.state.builder.AddFunction(
 		    spv::OpAtomicCompareExchange, TypeU32(ctx.state), old, pointer,
 		    ConstantU32(ctx.state, scope), ConstantU32(ctx.state, spv::MemorySemanticsMaskNone),

src/graphics/shader/recompiler/frontend/decode/MemoryOps.cpp

@@ -115,6 +115,7 @@ constexpr MemoryOpcodeInfo DS_OPCODE_LIST[] = {
     {0x27u, Opcode::DS_MIN_RTN_U32, 1, 32},      {0x28u, Opcode::DS_MAX_RTN_U32, 1, 32},
     {0x29u, Opcode::DS_AND_RTN_B32, 1, 32},      {0x2au, Opcode::DS_OR_RTN_B32, 1, 32},
     {0x2bu, Opcode::DS_XOR_RTN_B32, 1, 32},      {0x2du, Opcode::DS_WRXCHG_RTN_B32, 1, 32},
+    {0x30u, Opcode::DS_CMPST_RTN_B32, 1, 32},
     {0x35u, Opcode::DS_SWIZZLE_B32, 1, 32},      {0x36u, Opcode::DS_READ_B32, 1, 32},
     {0x37u, Opcode::DS_READ2_B32, 2, 32},        {0x38u, Opcode::DS_READ2ST64_B32, 2, 32},
     {0x39u, Opcode::DS_READ_I8, 1, 8, true},     {0x3au, Opcode::DS_READ_U8, 1, 8},
@@ -201,6 +202,7 @@ bool IsDsAtomicOpcode(Opcode opcode) {
 		case Opcode::DS_MAX_U32:
 		case Opcode::DS_MAX_RTN_U32:
 		case Opcode::DS_MAX_RTN_U64:
+		case Opcode::DS_CMPST_RTN_B32:
 		case Opcode::DS_CMPST_RTN_B64:
 		case Opcode::DS_AND_B32:
 		case Opcode::DS_AND_RTN_B32:
@@ -221,6 +223,7 @@ uint32_t DsSourceCount(Opcode opcode) {
 		case Opcode::DS_WRITE2ST64_B32:
 		case Opcode::DS_WRITE2_B64:
 		case Opcode::DS_WRITE2ST64_B64:
+		case Opcode::DS_CMPST_RTN_B32:
 		case Opcode::DS_CMPST_RTN_B64:
 		case Opcode::DS_MSKOR_B32: return 3u;
 		case Opcode::DS_MIN_F32:
@@ -455,6 +458,9 @@ void DecodeDs(uint32_t pc, std::span<const uint32_t> code, uint32_t word_index,
 	if (inst.opcode == Opcode::DS_SWIZZLE_B32 && inst.offset >= 0xe000u) {
 		SetUnsupported(inst, Family::DS, opcode, "DS swizzle FFT mode is not implemented");
 	}
+	if (inst.gds && inst.opcode == Opcode::DS_CMPST_RTN_B32) {
+		SetUnsupported(inst, Family::DS, opcode, "DS compare-store return B32 GDS variant is not implemented");
+	}
 	if (inst.gds &&
 	    (inst.opcode == Opcode::DS_SWIZZLE_B32 || inst.opcode == Opcode::DS_PERMUTE_B32 ||
 	     inst.opcode == Opcode::DS_BPERMUTE_B32 ||

src/graphics/shader/recompiler/frontend/decode/ShaderDecoder.cpp

@@ -718,6 +718,7 @@ std::string InstructionToString(const Instruction& inst) {
 		case Opcode::DS_MAX_U32:
 		case Opcode::DS_MAX_RTN_U32:
 		case Opcode::DS_MAX_RTN_U64:
+		case Opcode::DS_CMPST_RTN_B32:
 		case Opcode::DS_CMPST_RTN_B64:
 		case Opcode::DS_AND_B32:
 		case Opcode::DS_AND_RTN_B32:

src/graphics/shader/recompiler/frontend/decode/ShaderDecoder.h

@@ -632,6 +632,7 @@ enum class Opcode {
 	DS_MAX_U32,
 	DS_MAX_RTN_U32,
 	DS_MAX_RTN_U64,
+	DS_CMPST_RTN_B32,
 	DS_CMPST_RTN_B64,
 	DS_AND_B32,
 	DS_AND_RTN_B32,

src/graphics/shader/recompiler/frontend/translate/Memory.cpp

@@ -1085,6 +1085,8 @@ void Translator::EmitMemory(const Decoder::Instruction& inst) {
 			return DS_ATOMIC(inst, IR::ValueOpcode::SharedAtomicUMax32, true);
 		case Decoder::Opcode::DS_MAX_RTN_U64:
 			return DS_ATOMIC(inst, IR::ValueOpcode::SharedAtomicUMax64, true);
+		case Decoder::Opcode::DS_CMPST_RTN_B32:
+			return DS_ATOMIC(inst, IR::ValueOpcode::SharedAtomicCmpSwap32, true);
 		case Decoder::Opcode::DS_CMPST_RTN_B64:
 			return DS_ATOMIC(inst, IR::ValueOpcode::SharedAtomicCmpSwap64, true);
 		case Decoder::Opcode::DS_AND_B32:

src/graphics/shader/recompiler/ir/opcodes/ValueOpcodes.cpp

@@ -178,6 +178,7 @@ SharedAccess SharedAccessOf(ValueOpcode opcode) {
 		case ValueOpcode::SharedAtomicSMax32:
 		case ValueOpcode::SharedAtomicUMax32:
 		case ValueOpcode::SharedAtomicUMax64:
+		case ValueOpcode::SharedAtomicCmpSwap32:
 		case ValueOpcode::SharedAtomicCmpSwap64:
 		case ValueOpcode::SharedAtomicAnd32:
 		case ValueOpcode::SharedAtomicOr32:

src/graphics/shader/recompiler/ir/opcodes/ValueOpcodes.inc

@@ -307,6 +307,7 @@ VALUE_OPCODE(SharedAtomicUMin32, U32, U32, U32, U1)
 VALUE_OPCODE(SharedAtomicSMax32, U32, U32, U32, U1)
 VALUE_OPCODE(SharedAtomicUMax32, U32, U32, U32, U1)
 VALUE_OPCODE(SharedAtomicUMax64, U64, U32, U64, U1)
+VALUE_OPCODE(SharedAtomicCmpSwap32, U32, U32, U32, U32, U1)
 VALUE_OPCODE(SharedAtomicCmpSwap64, U64, U32, U64, U64, U1)
 VALUE_OPCODE(SharedAtomicAnd32, U32, U32, U32, U1)
 VALUE_OPCODE(SharedAtomicOr32, U32, U32, U32, U1)

src/kernel/fileSystem.cpp

@@ -338,14 +338,20 @@ static bool HasWindowsForbiddenFilenameCharacter(const std::string& relative_pat
 std::filesystem::path MountPoints::ResolvePath(const std::string& mounted_name) {
 	Common::LockGuard lock(m_mutex);
 
+	// Guests join mount points and names with extra slashes (e.g. "/addcont0//file").
+	std::string normalized = Common::FixFilenameSlash(mounted_name);
+	normalized.erase(std::unique(normalized.begin(), normalized.end(),
+	                             [](char a, char b) { return a == '/' && b == '/'; }),
+	                 normalized.end());
+
 	// Match the entire guest path so a mount root works with or without a trailing slash.
-	const auto mounted_path = Common::FixDirectorySlash(mounted_name);
+	const auto mounted_path = Common::FixDirectorySlash(normalized);
 	const auto it           = std::find_if(
 	    m_mount_pairs.begin(), m_mount_pairs.end(),
 	    [&mounted_path](const MountPair& p) { return mounted_path.starts_with(p.point); });
 	if (it != m_mount_pairs.end()) {
 		const auto& p = *it;
-		auto rel_path = Common::RemoveFirst(Common::FixFilenameSlash(mounted_name), p.point.size());
+		auto rel_path = Common::RemoveFirst(normalized, p.point.size());
 		while (rel_path.starts_with('/')) {
 			rel_path = Common::RemoveFirst(rel_path, 1);
 		}

src/libs/libAmpr.cpp

@@ -25,6 +25,9 @@
 #include <string>
 #include <thread>
 #include <unordered_map>
+#include <atomic>
+#include <cinttypes>
+#include <iterator>
 #include <variant>
 #include <vector>
 
@@ -176,6 +179,14 @@ static int GetHostPathStat(const std::filesystem::path& host_path, LibKernel::Fi
 	return OK;
 }
 
+// Mounts can appear after a failed lookup (e.g. additional content), so forget negative results.
+void InvalidateFailedResolves() {
+	std::scoped_lock lock(g_mutex);
+	for (auto it = g_resolved_paths.begin(); it != g_resolved_paths.end();) {
+		it = it->second.result != OK ? g_resolved_paths.erase(it) : std::next(it);
+	}
+}
+
 static int ResolveOnePath(const char* guest_path, uint32_t* id, uint64_t* size) {
 	if (guest_path == nullptr || guest_path[0] == '\0') {
 		return LibKernel::KERNEL_ERROR_EINVAL;
@@ -225,6 +236,10 @@ static int ResolveOnePath(const char* guest_path, uint32_t* id, uint64_t* size)
 				log_missing = true;
 			}
 		}
+		if (!log_missing && info.result == OK && path.starts_with("/addcont")) {
+			LOGF("\tAPR resolve: %s -> %s (%" PRIu64 " bytes)\n", guest_path,
+			     Common::PathToString(info.host_path).c_str(), info.file_size);
+		}
 		if (log_missing) {
 			LOGF("\tAPR resolve missing path: %s -> %s\n", guest_path, Common::PathToString(info.host_path).c_str());
 		}
@@ -1181,6 +1196,13 @@ static int ExecuteCommand(const CommandBufferState::Command& entry) {
 		uint64_t bytes_read = 0;
 		auto     result = ReadHostFileToGuest(host_path, command.file_offset, command.destination,
 		                                      command.size, &bytes_read);
+		static std::atomic<uint32_t> s_logged_dlc_reads {0};
+		if (host_path.filename() == "re_dlc_000.pak" && s_logged_dlc_reads.fetch_add(1) < 32) {
+			LOGF("\tAPR read dlc: id=0x%08" PRIx32 ", offset=0x%016" PRIx64 ", size=0x%016" PRIx64
+			     ", read=0x%016" PRIx64 ", result=0x%08" PRIx32 "\n",
+			     command.file_id, command.file_offset, command.size, bytes_read,
+			     static_cast<uint32_t>(result));
+		}
 		if (result != OK) {
 			LOGF("\tAPR submit read failed: id=0x%08" PRIx32 ", result=0x%08" PRIx32 ", path=%s\n",
 			     command.file_id, static_cast<uint32_t>(result), Common::PathToString(host_path).c_str());

src/libs/libAppContent.cpp

@@ -22,13 +22,16 @@
 
 namespace Libs {
 
+namespace AprShared {
+void InvalidateFailedResolves();
+}
+
 LIB_VERSION("AppContent", 1, "AppContentUtil", 1, 1);
 
 namespace AppContent {
 
 constexpr uint32_t APP_CONTENT_APPPARAM_SKU_FLAG_FULL = 3;
 constexpr int      APP_CONTENT_ERROR_PARAMETER        = -2133262334; /* 0x80D90002 */
-constexpr int      APP_CONTENT_ERROR_BUSY             = -2133262333; /* 0x80D90003 */
 constexpr int      APP_CONTENT_ERROR_NOT_MOUNTED      = -2133262332; /* 0x80D90004 */
 constexpr int      APP_CONTENT_ERROR_NOT_FOUND        = -2133262331; /* 0x80D90005 */
 constexpr int      APP_CONTENT_ERROR_MOUNT_FULL       = -2133262330; /* 0x80D90006 */
@@ -207,7 +210,10 @@ int KYTY_SYSV_ABI AppContentAddcontMount(uint32_t                         servic
 
 	for (const auto& m: g_addcont_mounts) {
 		if (m.label == entry->entitlement_label) {
-			return APP_CONTENT_ERROR_BUSY;
+			const auto guest_point = m.point.substr(0, m.point.size() - 1);
+			std::strncpy(mount_point->data, guest_point.c_str(), sizeof(mount_point->data) - 1);
+			LOGF("\t already mounted %s\n", guest_point.c_str());
+			return OK;
 		}
 	}
 
@@ -232,7 +238,15 @@ int KYTY_SYSV_ABI AppContentAddcontMount(uint32_t                         servic
 	LOGF("\t mounted %s -> %s\n", mount.point.c_str(),
 	     Common::PathToString(entry->mount_dir).c_str());
 
-	std::strncpy(mount_point->data, mount.point.c_str(), sizeof(mount_point->data) - 1);
+	AprShared::InvalidateFailedResolves();
+
+	// Titles scan /download0/pdlc for downloaded content; it must exist even when empty.
+	if (const auto pdlc = LibKernel::FileSystem::GetRealFilename("/download0/pdlc"); !pdlc.empty()) {
+		std::filesystem::create_directories(pdlc, ec);
+	}
+
+	const auto guest_point = mount.point.substr(0, mount.point.size() - 1);
+	std::strncpy(mount_point->data, guest_point.c_str(), sizeof(mount_point->data) - 1);
 	g_addcont_mounts.push_back(std::move(mount));
 
 	return OK;
@@ -251,8 +265,8 @@ int KYTY_SYSV_ABI AppContentAddcontUnmount(const AppContentMountPoint* mount_poi
 		return APP_CONTENT_ERROR_NOT_MOUNTED;
 	}
 
-	const std::string point(mount_point->data,
-	                        strnlen(mount_point->data, sizeof(mount_point->data)));
+	const std::string point = Common::FixDirectorySlash(
+	    std::string_view(mount_point->data, strnlen(mount_point->data, sizeof(mount_point->data))));
 
 	std::lock_guard lock(g_addcont_mutex);
 
@@ -263,6 +277,7 @@ int KYTY_SYSV_ABI AppContentAddcontUnmount(const AppContentMountPoint* mount_poi
 	}
 	LibKernel::FileSystem::Umount(point);
 	g_addcont_mounts.erase(it);
+	AprShared::InvalidateFailedResolves();
 
 	return OK;
 }

src/libs/libPlayGo.cpp

@@ -221,11 +221,17 @@ int KYTY_SYSV_ABI PlayGoGetChunkId(int handle, uint16_t* out_chunk_id_list,
 	if (out_entries == nullptr) {
 		return PLAYGO_ERROR_BAD_POINTER;
 	}
-	if (number_of_entries != 0 && out_chunk_id_list == nullptr) {
-		return PLAYGO_ERROR_BAD_POINTER;
+	if (out_chunk_id_list != nullptr && number_of_entries == 0) {
+		return PLAYGO_ERROR_BAD_SIZE;
 	}
 	ensure_chunks_loaded();
 
+	// A null output buffer asks for the total chunk count.
+	if (out_chunk_id_list == nullptr) {
+		*out_entries = g_chunks_num;
+		return OK;
+	}
+
 	const uint32_t entries = std::min(number_of_entries, g_chunks_num);
 	for (uint32_t i = 0; i < entries; i++) {
 		out_chunk_id_list[i] = static_cast<uint16_t>(i);

tests/KernelFileSystemTests.cpp

@@ -413,7 +413,9 @@ void TestAddContent(const std::filesystem::path& root) {
   Check(mount(0, nullptr, &point) == static_cast<int>(0x80d90002u) &&
             list(0, nullptr, 0, nullptr) == static_cast<int>(0x817d0002u),
         "null add-on parameters return parameter errors");
-  Check(mount(0, &info[3].label, &point) == OK, "mount owned add-on");
+  Check(mount(0, &info[3].label, &point) == OK &&
+            !std::string_view(point.data).ends_with('/'),
+        "mount owned add-on without trailing slash");
   const std::string mounted_file = std::string(point.data) + "/payload.txt";
   const int fd = FileSystem::KernelOpen(mounted_file.c_str(), 0, 0);
   std::array<char, 11> payload {};
@@ -422,8 +424,9 @@ void TestAddContent(const std::filesystem::path& root) {
             FileSystem::KernelClose(fd) == OK,
         "guest reads files from the selected title's add-on");
   MountPoint repeated {};
-  Check(mount(0, &info[3].label, &repeated) == static_cast<int>(0x80d90003u),
-        "duplicate mount returns BUSY");
+  Check(mount(0, &info[3].label, &repeated) == OK &&
+            std::strcmp(repeated.data, point.data) == 0,
+        "duplicate mount returns the same mount point");
   Check(unmount(&point) == OK && FileSystem::GetRealFilename(mounted_file).empty() &&
             unmount(&point) == static_cast<int>(0x80d90004u),
         "unmount removes mapping and repeated unmount reports NOT_MOUNTED");

tests/ShaderRecompilerComputeTests.cpp

@@ -21015,6 +21015,7 @@ CoverageClass ClassifyOpcode(ShaderOpcode opcode,
   case Opcode::DS_ADD_U32:
   case Opcode::DS_ADD_U64:
   case Opcode::DS_MAX_RTN_U64:
+  case Opcode::DS_CMPST_RTN_B32:
   case Opcode::DS_CMPST_RTN_B64:
   case Opcode::DS_ADD_RTN_U32:
   case Opcode::DS_SUB_U32:
@@ -34698,6 +34699,60 @@ TestCase DsAtomicReturn64() {
   return test;
 }
 
+TestCase DsCompareStoreReturn32() {
+  using O = ShaderOpcode;
+  TestCase test;
+  test.name = "DsCompareStoreReturn32";
+  auto &code = test.code;
+  const auto result = [&](u32 reg, u32 value) {
+    AppendStoreVgpr(&code, reg, static_cast<u32>(test.expected.size()));
+    test.expected.push_back(value);
+  };
+  struct Case { u32 before, compare, replacement; };
+  constexpr std::array cases{Case{0x12345678u, 0x12345678u, 0x9abcdef0u},
+                             Case{0x12345678u, 0x9abcdef0u, 0x12345678u},
+                             Case{0x80000000u, 0u, 0x7fffffffu},
+                             Case{UINT32_MAX, UINT32_MAX, 0u}};
+  AppendVMovU32(&code, 7, 0);
+  for (const auto &item : cases) {
+    AppendVMovLiteral(&code, 2, item.before);
+    code.push_back(EncodeDs0(0x0d, 8));
+    code.push_back(EncodeDs1(0, 2, 7));
+    AppendVMovLiteral(&code, 5, item.compare);
+    AppendVMovLiteral(&code, 19, item.replacement);
+    AppendVMovU32(&code, 4, 8);
+    // CS04b812daaacd532f pc 0x3e8: DATA compares, DATA2 replaces, VDst aliases ADDR.
+    code.insert(code.end(), {0xd8c00000u, 0x04130504u});
+    result(4, item.before);
+    code.push_back(EncodeDs0(0x36, 8));
+    code.push_back(EncodeDs1(8, 0, 7));
+    result(8, item.before == item.compare ? item.replacement : item.before);
+  }
+  AppendVMovU32(&code, 5, 0);
+  AppendVMovU32(&code, 4, 12); // Past the three LDS DWORDs.
+  code.insert(code.end(), {0xd8c00000u, 0x04130504u});
+  result(4, 0);
+  AppendVMovLiteral(&code, 2, 0x12345678u);
+  code.push_back(EncodeDs0(0x0d, 8));
+  code.push_back(EncodeDs1(0, 2, 7));
+  AppendVMovLiteral(&code, 5, 0x12345678u);
+  AppendVMovU32(&code, 4, 8);
+  code.push_back(EncodeSMovB32(126, InlineU32(0)));
+  code.insert(code.end(), {0xd8c00000u, 0x04130504u});
+  code.push_back(EncodeSMovB32(126, InlineU32(1)));
+  result(4, 8); // An inactive lane keeps its destination and leaves memory alone.
+  code.push_back(EncodeDs0(0x36, 8));
+  code.push_back(EncodeDs1(8, 0, 7));
+  result(8, 0x12345678u);
+  AppendEnd(&code);
+  test.compute_info.lds_size_dwords = 3;
+  test.opcodes = {O::V_MOV_B32, O::S_MOV_B32, O::DS_WRITE_B32, O::DS_CMPST_RTN_B32,
+                  O::DS_READ_B32, O::BUFFER_STORE_DWORD, O::S_ENDPGM};
+  test.required_spirv = {"OpAtomicCompareExchange %uint"};
+  test.forbidden_spirv = {"OpLoopMerge"};
+  return test;
+}
+
 TestCase DsAtomic64Contention(bool add, u32 wave_size) {
   using O = ShaderOpcode;
   TestCase test;
@@ -42276,6 +42331,7 @@ std::vector<TestCase> MakeCases() {
   }
   AddCase(DsAtomicReturnVariants);
   AddCase(DsAtomicReturn64);
+  AddCase(DsCompareStoreReturn32);
   for (bool add : {false, true}) {
     cases.push_back(DsAtomic64Bounds(add));
     for (u32 wave_size : {32, 64}) {
@@ -47800,7 +47856,8 @@ int main(int argc, char **argv) {
     RunCase(&vulkan, DsWideLdsPartialBounds());
     RunCase(&vulkan, DsAtomic64Bounds(false));
     RunCase(&vulkan, DsAtomic64Bounds(true));
-    for (auto test : {DsWideLdsPartialBounds(), DsAtomic64Bounds(false), DsAtomic64Bounds(true), DsAtomicReturn64()}) {
+    for (auto test : {DsWideLdsPartialBounds(), DsAtomic64Bounds(false), DsAtomic64Bounds(true), DsAtomicReturn64(),
+                      DsCompareStoreReturn32()}) {
       test.compute_info.lds_storage = true;
       std::erase(test.required_spirv, "WorkgroupMemoryExplicitLayoutKHR");
       test.required_spirv.push_back("StorageBuffer");

tests/shaderCfgTests.cpp

@@ -8119,6 +8119,24 @@ void TestDsReturningAtomic64Decoder() {
         "captured DS_CMPST_RTN_B64 lost its comparison/replacement pairs or aliases");
 }
 
+void TestDsCompareStore32Decoder() {
+  using namespace ShaderRecompiler::Decoder;
+  // CS04b812daaacd532f pc 0x3e8 (AC Valhalla, #281).
+  const uint32_t words[] = {0xd8c00000u, 0x04130504u};
+  Instruction decoded;
+  DecodeInstruction(words, 0u, decoded);
+  Check(decoded.opcode == Opcode::DS_CMPST_RTN_B32 && decoded.word_count == 2u &&
+            decoded.data_dwords == 1u && decoded.src_count == 3u && decoded.src0.reg == 4u &&
+            decoded.src1.reg == 5u && decoded.src2.reg == 19u && decoded.dst.reg == 4u &&
+            decoded.offset == 0u && !decoded.gds,
+        "captured DS_CMPST_RTN_B32 lost its comparison/replacement order or aliases");
+
+  const uint32_t gds_words[] = {words[0] | (1u << 17u), words[1]};
+  DecodeInstruction(gds_words, 0u, decoded);
+  Check(decoded.opcode == Opcode::UNSUPPORTED && decoded.word_count == 2u && decoded.gds,
+        "DS_CMPST_RTN_B32 must reject the unimplemented GDS variant");
+}
+
 void TestDsFloatMinMaxDecoder() {
   using namespace ShaderRecompiler::Decoder;
   for (bool max_value : {false, true}) {
@@ -16480,6 +16498,7 @@ int main() {
   TestScalarAshrI64Decoder();
   TestImageAtomicWidthDecoder();
   TestDsReturningAtomic64Decoder();
+  TestDsCompareStore32Decoder();
   TestDsFloatMinMaxDecoder();
   TestNewShaderDecoderArchitecture();
   TestImageAddressOperands();