From b331f241645fce74a4377863baa3a2135854c457 Mon Sep 17 00:00:00 2001
From: offtkp <parisoplop@gmail.com>
Date: Mon, 2 Sep 2024 04:47:11 +0300
Subject: [PATCH] Implement S_SUB_I32 and flags for S_SUB_U32

---
 .../frontend/translate/scalar_alu.cpp          | 18 +++++++++++++++---
 .../frontend/translate/translate.h             |  1 +
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/shader_recompiler/frontend/translate/scalar_alu.cpp b/src/shader_recompiler/frontend/translate/scalar_alu.cpp
index 8193193a1..8e25790bc 100644
--- a/src/shader_recompiler/frontend/translate/scalar_alu.cpp
+++ b/src/shader_recompiler/frontend/translate/scalar_alu.cpp
@@ -70,8 +70,9 @@ void Translator::EmitScalarAlu(const GcnInst& inst) {
         case Opcode::S_ADDC_U32:
             return S_ADDC_U32(inst);
         case Opcode::S_SUB_U32:
-        case Opcode::S_SUB_I32:
             return S_SUB_U32(inst);
+        case Opcode::S_SUB_I32:
+            return S_SUB_I32(inst);
         case Opcode::S_MIN_U32:
             return S_MIN_U32(inst);
         case Opcode::S_MAX_U32:
@@ -519,8 +520,19 @@ void Translator::S_SUB_U32(const GcnInst& inst) {
     const IR::U32 src0{GetSrc(inst.src[0])};
     const IR::U32 src1{GetSrc(inst.src[1])};
     SetDst(inst.dst[0], ir.ISub(src0, src1));
-    // TODO: Carry out
-    ir.SetScc(ir.Imm1(false));
+    ir.SetScc(ir.IGreaterThan(src1, src0, false));
+}
+
+void Translator::S_SUB_I32(const GcnInst& inst) {
+    const IR::U32 src0{GetSrc(inst.src[0])};
+    const IR::U32 src1{GetSrc(inst.src[1])};
+    const IR::U32 result = ir.ISub(src0, src1);
+    SetDst(inst.dst[0], result);
+    const IR::U32 sign_mask = ir.Imm32(1 << 31);
+    const IR::U32 sign0 = ir.BitwiseAnd(src0, sign_mask);
+    const IR::U32 sign1 = ir.BitwiseAnd(src1, sign_mask);
+    const IR::U32 signr = ir.BitwiseAnd(result, sign_mask);
+    ir.SetScc(ir.LogicalAnd(ir.INotEqual(sign0, sign1), ir.INotEqual(sign0, signr)));
 }
 
 void Translator::S_GETPC_B64(u32 pc, const GcnInst& inst) {
diff --git a/src/shader_recompiler/frontend/translate/translate.h b/src/shader_recompiler/frontend/translate/translate.h
index f1619e810..e29f98384 100644
--- a/src/shader_recompiler/frontend/translate/translate.h
+++ b/src/shader_recompiler/frontend/translate/translate.h
@@ -95,6 +95,7 @@ public:
     void S_NOT_B64(const GcnInst& inst);
     void S_BREV_B32(const GcnInst& inst);
     void S_ADD_U32(const GcnInst& inst);
+    void S_SUB_I32(const GcnInst& inst);
     void S_SUB_U32(const GcnInst& inst);
     void S_GETPC_B64(u32 pc, const GcnInst& inst);
     void S_ADDC_U32(const GcnInst& inst);