1 files changed, 133 insertions, 0 deletions
diff --git a/src/Ryujinx.Cpu/LightningJit/Arm32/Target/Arm64/InstEmitVfpCompare.cs b/src/Ryujinx.Cpu/LightningJit/Arm32/Target/Arm64/InstEmitVfpCompare.cs
new file mode 100644
index 00000000..f5f30609
--- /dev/null
+++ b/src/Ryujinx.Cpu/LightningJit/Arm32/Target/Arm64/InstEmitVfpCompare.cs
@@ -0,0 +1,133 @@
+using Ryujinx.Cpu.LightningJit.CodeGen;
+using System;
+using System.Diagnostics;
+
+namespace Ryujinx.Cpu.LightningJit.Arm32.Target.Arm64
+{
+    static class InstEmitVfpCompare
+    {
+        public static void VcmpI(CodeGenContext context, uint cond, uint rd, uint size)
+        {
+            EmitVcmpVcmpe(context, cond, rd, 0, size, zero: true, e: false);
+        }
+
+        public static void VcmpR(CodeGenContext context, uint cond, uint rd, uint rm, uint size)
+        {
+            EmitVcmpVcmpe(context, cond, rd, rm, size, zero: false, e: false);
+        }
+
+        public static void VcmpeI(CodeGenContext context, uint cond, uint rd, uint size)
+        {
+            EmitVcmpVcmpe(context, cond, rd, 0, size, zero: true, e: true);
+        }
+
+        public static void VcmpeR(CodeGenContext context, uint cond, uint rd, uint rm, uint size)
+        {
+            EmitVcmpVcmpe(context, cond, rd, rm, size, zero: false, e: true);
+        }
+
+        private static void EmitVcmpVcmpe(CodeGenContext context, uint cond, uint rd, uint rm, uint size, bool zero, bool e)
+        {
+            Debug.Assert(size == 1 || size == 2 || size == 3);
+
+            bool singleRegs = size != 3;
+            uint ftype = size ^ 2u;
+            uint opc = zero ? 1u : 0u;
+
+            using ScopedRegister rdReg = InstEmitNeonCommon.MoveScalarToSide(context, rd, singleRegs);
+            ScopedRegister rmReg;
+            Operand rmOrZero;
+
+            if (zero)
+            {
+                rmReg = default;
+                rmOrZero = new Operand(0, RegisterType.Vector, OperandType.V128);
+            }
+            else
+            {
+                rmReg = InstEmitNeonCommon.MoveScalarToSide(context, rm, singleRegs);
+                rmOrZero = rmReg.Operand;
+            }
+
+            using ScopedRegister oldFlags = context.RegisterAllocator.AllocateTempGprRegisterScoped();
+
+            bool canPeepholeOptimize = CanFuseVcmpVmrs(context, cond);
+            if (!canPeepholeOptimize)
+            {
+                InstEmitCommon.GetCurrentFlags(context, oldFlags.Operand);
+            }
+
+            if (e)
+            {
+                context.Arm64Assembler.FcmpeFloat(rdReg.Operand, rmOrZero, opc, ftype);
+            }
+            else
+            {
+                context.Arm64Assembler.FcmpFloat(rdReg.Operand, rmOrZero, opc, ftype);
+            }
+
+            // Save result flags from the FCMP operation on FPSCR register, then restore the old flags if needed.
+
+            WriteUpdateFpsrNzcv(context);
+
+            if (!canPeepholeOptimize)
+            {
+                InstEmitCommon.RestoreNzcvFlags(context, oldFlags.Operand);
+            }
+
+            if (!zero)
+            {
+                rmReg.Dispose();
+            }
+        }
+
+        private static void WriteUpdateFpsrNzcv(CodeGenContext context)
+        {
+            using ScopedRegister fpsrRegister = context.RegisterAllocator.AllocateTempGprRegisterScoped();
+            using ScopedRegister flagsRegister = context.RegisterAllocator.AllocateTempGprRegisterScoped();
+
+            Operand ctx = InstEmitSystem.Register(context.RegisterAllocator.FixedContextRegister);
+
+            context.Arm64Assembler.LdrRiUn(fpsrRegister.Operand, ctx, NativeContextOffsets.FpFlagsBaseOffset);
+
+            InstEmitCommon.GetCurrentFlags(context, flagsRegister.Operand);
+
+            context.Arm64Assembler.Bfi(fpsrRegister.Operand, flagsRegister.Operand, 28, 4);
+            context.Arm64Assembler.StrRiUn(fpsrRegister.Operand, ctx, NativeContextOffsets.FpFlagsBaseOffset);
+        }
+
+        private static bool CanFuseVcmpVmrs(CodeGenContext context, uint vcmpCond)
+        {
+            // Conditions might be different for the VCMP and VMRS instructions if they are inside a IT block,
+            // we don't bother to check right now, so just always skip if inside an IT block.
+            if (context.InITBlock)
+            {
+                return false;
+            }
+
+            InstInfo nextInfo = context.PeekNextInstruction();
+
+            // We're looking for a VMRS instructions.
+            if (nextInfo.Name != InstName.Vmrs)
+            {
+                return false;
+            }
+
+            // Conditions must match.
+            if (vcmpCond != (nextInfo.Encoding >> 28))
+            {
+                return false;
+            }
+
+            // Reg must be 1, Rt must be PC indicating VMRS to PSTATE.NZCV.
+            if (((nextInfo.Encoding >> 16) & 0xf) != 1 || ((nextInfo.Encoding >> 12) & 0xf) != RegisterUtils.PcRegister)
+            {
+                return false;
+            }
+
+            context.SetSkipNextInstruction();
+
+            return true;
+        }
+    }
+}