test(shader): cover SAshrI64 translation (#914)

tests/SharpEmu.ShaderCompiler.Tests/Gen5ScalarArithmeticShift64Tests.cs

@@ -0,0 +1,67 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Buffers.Binary;
+using SharpEmu.HLE;
+using SharpEmu.ShaderCompiler.Metal;
+using SharpEmu.ShaderCompiler.Tests.Resources;
+using SharpEmu.ShaderCompiler.Vulkan;
+using Xunit;
+using static SharpEmu.ShaderCompiler.Tests.Resources.ResourceTestProgram;
+
+namespace SharpEmu.ShaderCompiler.Tests;
+
+public sealed class Gen5ScalarArithmeticShift64Tests
+{
+    [Fact]
+    public void DecodeGfx10Encoding()
+    {
+        var instruction = Decode(0x91880604);
+        Assert.Equal("SAshrI64", instruction.Opcode);
+        Assert.Equal(Gen5ShaderEncoding.Sop2, instruction.Encoding);
+        Assert.Equal(Gen5Operand.Scalar(4), instruction.Sources[0]);
+        Assert.Equal(Gen5Operand.Scalar(6), instruction.Sources[1]);
+        Assert.Equal(Gen5Operand.Scalar(8), Assert.Single(instruction.Destinations));
+    }
+
+    [Fact]
+    public void CompilesOnBothBackends()
+    {
+        var program = Program(
+            Sop2(0, "SAshrI64", 8, Gen5Operand.Scalar(4), Gen5Operand.Scalar(6)),
+            EndProgram(4));
+        var (plan, resources, layout) = Prepare(program);
+        var request = new ShaderCompileRequest(plan, resources, layout) { LocalSizeX = 1, ThreadCountX = 1 };
+
+        Assert.True(Gen5SpirvTranslator.TryCompileProgram(request, out var spirv, out var spirvError), spirvError);
+        var inspector = new SpirvModuleInspector(spirv.Spirv);
+        Assert.Contains((ushort)SpirvOp.ShiftRightArithmetic, inspector.Opcodes);
+
+        Assert.True(Gen5MslTranslator.TryCompileProgram(request, out var metal, out var metalError), metalError);
+        Assert.Contains("as_type<long>", metal.Source);
+        Assert.Contains("& 63u", metal.Source);
+    }
+
+    private static Gen5ShaderInstruction Decode(uint word)
+    {
+        var bytes = new byte[8];
+        BinaryPrimitives.WriteUInt32LittleEndian(bytes, word);
+        BinaryPrimitives.WriteUInt32LittleEndian(bytes.AsSpan(4), 0xBF810000);
+        var context = new CpuContext(new InstructionMemory(bytes), Generation.Gen5);
+        Assert.True(Gen5ShaderTranslator.TryDecodeProgram(context, 0x1000, out var program, out var error), error);
+        return program.Instructions[0];
+    }
+
+    private sealed class InstructionMemory(byte[] bytes) : ICpuMemory
+    {
+        public bool TryRead(ulong address, Span<byte> destination)
+        {
+            if (address < 0x1000 || destination.Length > bytes.Length ||
+                address - 0x1000 > (ulong)(bytes.Length - destination.Length)) return false;
+            bytes.AsSpan((int)(address - 0x1000), destination.Length).CopyTo(destination);
+            return true;
+        }
+
+        public bool TryWrite(ulong address, ReadOnlySpan<byte> source) => false;
+    }
+}