CPU/Recompiler: Detect move instructions and forward to PGXP

Fixes holes in polygons in Gran Turismo 1 + 2 with PGXP enabled.

src/core/cpu_recompiler_code_generator.cpp

@@ -1301,6 +1301,7 @@ bool CodeGenerator::Compile_Add(const CodeBlockInstruction& cbi)
      (cbi.instruction.op == InstructionOp::funct && cbi.instruction.r.funct == InstructionFunct::add));
 
   Value lhs, rhs;
+  Reg lhs_src;
   Reg dest;
   switch (cbi.instruction.op)
   {
@@ -1309,6 +1310,7 @@ bool CodeGenerator::Compile_Add(const CodeBlockInstruction& cbi)
     {
       // rt <- rs + sext(imm)
       dest = cbi.instruction.i.rt;
+      lhs_src = cbi.instruction.i.rs;
       lhs = m_register_cache.ReadGuestRegister(cbi.instruction.i.rs);
       rhs = Value::FromConstantU32(cbi.instruction.i.imm_sext32());
     }
@@ -1318,6 +1320,7 @@ bool CodeGenerator::Compile_Add(const CodeBlockInstruction& cbi)
     {
       Assert(cbi.instruction.r.funct == InstructionFunct::add || cbi.instruction.r.funct == InstructionFunct::addu);
       dest = cbi.instruction.r.rd;
+      lhs_src = cbi.instruction.r.rs;
       lhs = m_register_cache.ReadGuestRegister(cbi.instruction.r.rs);
       rhs = m_register_cache.ReadGuestRegister(cbi.instruction.r.rt);
     }
@@ -1328,6 +1331,13 @@ bool CodeGenerator::Compile_Add(const CodeBlockInstruction& cbi)
       return false;
   }
 
+  // detect register moves and handle them for pgxp
+  if (g_settings.gpu_pgxp_enable && rhs.HasConstantValue(0))
+  {
+    EmitFunctionCall(nullptr, &PGXP::CPU_MOVE,
+                     Value::FromConstantU32((static_cast<u32>(dest) << 8) | (static_cast<u32>(lhs_src))), lhs);
+  }
+
   Value result = AddValues(lhs, rhs, check_overflow);
   if (check_overflow)
     GenerateExceptionExit(cbi, Exception::Ov, Condition::Overflow);

src/core/pgxp.cpp

@@ -870,6 +870,13 @@ void CPU_SW(u32 instr, u32 rtVal, u32 addr)
   WriteMem(&CPU_reg[rt(instr)], addr);
 }
 
+void CPU_MOVE(u32 rd_and_rs, u32 rsVal)
+{
+  const u32 Rs = (rd_and_rs & 0xFFu);
+  Validate(&CPU_reg[Rs], rsVal);
+  CPU_reg[(rd_and_rs >> 8)] = CPU_reg[Rs];
+}
+
 void CPU_ADDI(u32 instr, u32 rtVal, u32 rsVal)
 {
   // Rt = Rs + Imm (signed)

src/core/pgxp.h

@@ -52,6 +52,7 @@ void CPU_LBx(u32 instr, u32 rtVal, u32 addr);
 void CPU_SB(u32 instr, u8 rtVal, u32 addr);
 void CPU_SH(u32 instr, u16 rtVal, u32 addr);
 void CPU_SW(u32 instr, u32 rtVal, u32 addr);
+void CPU_MOVE(u32 rd_and_rs, u32 rsVal);
 
 // Arithmetic with immediate value
 void CPU_ADDI(u32 instr, u32 rtVal, u32 rsVal);