CPU/Recompiler: Implement slt/sltu/slti/sltiu

src/core/cpu_recompiler_code_generator.cpp

@@ -101,15 +101,20 @@ bool CodeGenerator::CompileInstruction(const CodeBlockInstruction& cbi)
       result = Compile_Branch(cbi);
       break;
 
-    case InstructionOp::lui:
-      result = Compile_lui(cbi);
-      break;
-
     case InstructionOp::addi:
     case InstructionOp::addiu:
       result = Compile_Add(cbi);
       break;
 
+    case InstructionOp::slti:
+    case InstructionOp::sltiu:
+      result = Compile_SetLess(cbi);
+      break;
+
+    case InstructionOp::lui:
+      result = Compile_lui(cbi);
+      break;
+
     case InstructionOp::funct:
     {
       switch (cbi.instruction.r.funct)
@@ -151,6 +156,11 @@ bool CodeGenerator::CompileInstruction(const CodeBlockInstruction& cbi)
           result = Compile_Multiply(cbi);
           break;
 
+        case InstructionFunct::slt:
+        case InstructionFunct::sltu:
+          result = Compile_SetLess(cbi);
+          break;
+
         case InstructionFunct::jr:
         case InstructionFunct::jalr:
           result = Compile_Branch(cbi);
@@ -1148,6 +1158,43 @@ bool CodeGenerator::Compile_Multiply(const CodeBlockInstruction& cbi)
   return true;
 }
 
+bool CodeGenerator::Compile_SetLess(const CodeBlockInstruction& cbi)
+{
+  InstructionPrologue(cbi, 1);
+
+  const bool signed_comparison =
+    (cbi.instruction.op == InstructionOp::slti ||
+     (cbi.instruction.op == InstructionOp::funct && cbi.instruction.r.funct == InstructionFunct::slt));
+
+  Reg dest;
+  Value lhs, rhs;
+  if (cbi.instruction.op == InstructionOp::slti || cbi.instruction.op == InstructionOp::sltiu)
+  {
+    // rt <- rs < {z,s}ext(imm)
+    dest = cbi.instruction.i.rt;
+    lhs = m_register_cache.ReadGuestRegister(cbi.instruction.i.rs, true, true);
+    rhs = Value::FromConstantU32(cbi.instruction.i.imm_sext32());
+  }
+  else
+  {
+    // rd <- rs < rt
+    dest = cbi.instruction.r.rd;
+    lhs = m_register_cache.ReadGuestRegister(cbi.instruction.r.rs, true, true);
+    rhs = m_register_cache.ReadGuestRegister(cbi.instruction.r.rt);
+  }
+
+  // flush the old value which might free up a register
+  m_register_cache.InvalidateGuestRegister(dest);
+
+  Value result = m_register_cache.AllocateScratch(RegSize_32);
+  EmitCmp(lhs.host_reg, rhs);
+  EmitSetConditionResult(result.host_reg, result.size, signed_comparison ? Condition::Less : Condition::Below);
+  m_register_cache.WriteGuestRegister(dest, std::move(result));
+
+  InstructionEpilogue(cbi);
+  return true;
+}
+
 bool CodeGenerator::Compile_Branch(const CodeBlockInstruction& cbi)
 {
   // Force sync since we branches are PC-relative.
@@ -1211,7 +1258,7 @@ bool CodeGenerator::Compile_Branch(const CodeBlockInstruction& cbi)
       EmitCmp(lhs.host_reg, Value::FromConstantU32(0));
 
       const Condition condition =
-        (cbi.instruction.op == InstructionOp::bgtz) ? Condition::Greater : Condition::LessOrEqual;
+        (cbi.instruction.op == InstructionOp::bgtz) ? Condition::Greater : Condition::LessEqual;
       EmitBranch(condition, Reg::count, false, std::move(branch_target));
     }
     break;
@@ -1253,4 +1300,5 @@ bool CodeGenerator::Compile_lui(const CodeBlockInstruction& cbi)
   InstructionEpilogue(cbi);
   return true;
 }
+
 } // namespace CPU::Recompiler

src/core/cpu_recompiler_code_generator.h

@@ -61,6 +61,7 @@ public:
   void EmitXor(HostReg to_reg, const Value& value);
   void EmitTest(HostReg to_reg, const Value& value);
   void EmitNot(HostReg to_reg, RegSize size);
+  void EmitSetConditionResult(HostReg to_reg, RegSize to_size, Condition condition);
 
   void EmitLoadGuestRegister(HostReg host_reg, Reg guest_reg);
   void EmitStoreGuestRegister(Reg guest_reg, const Value& value);
@@ -181,6 +182,7 @@ private:
   bool Compile_Add(const CodeBlockInstruction& cbi);
   bool Compile_Subtract(const CodeBlockInstruction& cbi);
   bool Compile_Multiply(const CodeBlockInstruction& cbi);
+  bool Compile_SetLess(const CodeBlockInstruction& cbi);
   bool Compile_Branch(const CodeBlockInstruction& cbi);
   bool Compile_lui(const CodeBlockInstruction& cbi);
 

src/core/cpu_recompiler_code_generator_x64.cpp

@@ -1081,6 +1081,75 @@ void CodeGenerator::EmitNot(HostReg to_reg, RegSize size)
   }
 }
 
+void CodeGenerator::EmitSetConditionResult(HostReg to_reg, RegSize to_size, Condition condition)
+{
+  switch (condition)
+  {
+    case Condition::Always:
+      m_emit->mov(GetHostReg8(to_reg), 1);
+      break;
+
+    case Condition::NotEqual:
+      m_emit->setne(GetHostReg8(to_reg));
+      break;
+
+    case Condition::Equal:
+      m_emit->sete(GetHostReg8(to_reg));
+      break;
+
+    case Condition::Overflow:
+      m_emit->seto(GetHostReg8(to_reg));
+      break;
+
+    case Condition::Greater:
+      m_emit->setg(GetHostReg8(to_reg));
+      break;
+
+    case Condition::GreaterEqual:
+      m_emit->setge(GetHostReg8(to_reg));
+      break;
+
+    case Condition::Less:
+      m_emit->setl(GetHostReg8(to_reg));
+      break;
+
+    case Condition::LessEqual:
+      m_emit->setle(GetHostReg8(to_reg));
+      break;
+
+    case Condition::Negative:
+      m_emit->sets(GetHostReg8(to_reg));
+      break;
+
+    case Condition::PositiveOrZero:
+      m_emit->setns(GetHostReg8(to_reg));
+      break;
+
+    case Condition::Above:
+      m_emit->seta(GetHostReg8(to_reg));
+      break;
+
+    case Condition::AboveEqual:
+      m_emit->setae(GetHostReg8(to_reg));
+      break;
+
+    case Condition::Below:
+      m_emit->setb(GetHostReg8(to_reg));
+      break;
+
+    case Condition::BelowEqual:
+      m_emit->setbe(GetHostReg8(to_reg));
+      break;
+
+    default:
+      UnreachableCode();
+      break;
+  }
+
+  if (to_size != RegSize_8)
+    EmitZeroExtend(to_reg, to_size, to_reg, RegSize_8);
+}
+
 u32 CodeGenerator::PrepareStackForCall()
 {
   // we assume that the stack is unaligned at this point
@@ -1634,7 +1703,7 @@ static void EmitConditionalJump(Condition condition, bool invert, Xbyak::CodeGen
       invert ? emit->jnl(label) : emit->jl(label);
       break;
 
-    case Condition::LessOrEqual:
+    case Condition::LessEqual:
       invert ? emit->jnle(label) : emit->jle(label);
       break;
 
@@ -1646,6 +1715,22 @@ static void EmitConditionalJump(Condition condition, bool invert, Xbyak::CodeGen
       invert ? emit->js(label) : emit->jns(label);
       break;
 
+    case Condition::Above:
+      invert ? emit->jna(label) : emit->ja(label);
+      break;
+
+    case Condition::AboveEqual:
+      invert ? emit->jnae(label) : emit->jae(label);
+      break;
+
+    case Condition::Below:
+      invert ? emit->jnb(label) : emit->jb(label);
+      break;
+
+    case Condition::BelowEqual:
+      invert ? emit->jnbe(label) : emit->jbe(label);
+      break;
+
     default:
       UnreachableCode();
       break;

src/core/cpu_recompiler_types.h

@@ -32,10 +32,14 @@ enum class Condition: u8
   Overflow,
   Greater,
   GreaterEqual,
-  LessOrEqual,
+  LessEqual,
   Less,
   Negative,
   PositiveOrZero,
+  Above,      // unsigned variant of Greater
+  AboveEqual, // unsigned variant of GreaterEqual
+  Below,      // unsigned variant of Less
+  BelowEqual, // unsigned variant of LessEqual
 
   NotZero = NotEqual,
   Zero = Equal