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CPU: Don't stall until GTE completion on write 

Apparently this is what the real CPU does, and some very optimized
code can run slower if we stall early.

Obviously if you write to a register being read by the command,
things are going to break.
This commit is contained in:
Stenzek 2025-02-14 23:34:10 +10:00
parent 7d80a74dc3
commit 8772c336ec
No known key found for this signature in database
2 changed files with 8 additions and 6 deletions
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8
src/core/cpu_core.cpp
View File

@ -1851,8 +1851,6 @@ restart_instruction:
return;
}
StallUntilGTEComplete();
if (inst.cop.IsCommonInstruction())
{
// TODO: Combine with cop0.
@ -1860,6 +1858,8 @@ restart_instruction:
{
case CopCommonInstruction::cfcn:
{
StallUntilGTEComplete();
const u32 value = GTE::ReadRegister(static_cast<u32>(inst.r.rd.GetValue()) + 32);
WriteRegDelayed(inst.r.rt, value);
@ -1880,6 +1880,8 @@ restart_instruction:
case CopCommonInstruction::mfcn:
{
StallUntilGTEComplete();
const u32 value = GTE::ReadRegister(static_cast<u32>(inst.r.rd.GetValue()));
WriteRegDelayed(inst.r.rt, value);
@ -1906,6 +1908,7 @@ restart_instruction:
}
else
{
StallUntilGTEComplete();
GTE::ExecuteInstruction(inst.bits);
}
}
@ -1925,7 +1928,6 @@ restart_instruction:
if (!ReadMemoryWord(addr, &value))
return;
StallUntilGTEComplete();
GTE::WriteRegister(ZeroExtend32(static_cast<u8>(inst.i.rt.GetValue())), value);
if constexpr (pgxp_mode >= PGXPMode::Memory)

6
src/core/cpu_recompiler.cpp
View File

@ -1301,8 +1301,8 @@ void CPU::Recompiler::Recompiler::CompileInstruction()
{
case CopCommonInstruction::mfcn: if (inst->r.rt != Reg::zero) { CompileTemplate(nullptr, &Recompiler::Compile_mfc2, nullptr, TF_GTE_STALL); } break;
case CopCommonInstruction::cfcn: if (inst->r.rt != Reg::zero) { CompileTemplate(nullptr, &Recompiler::Compile_mfc2, nullptr, TF_GTE_STALL); } break;
case CopCommonInstruction::mtcn: CompileTemplate(nullptr, &Recompiler::Compile_mtc2, PGXPFN(CPU_MTC2), TF_GTE_STALL | TF_READS_T | TF_PGXP_WITHOUT_CPU); break;
case CopCommonInstruction::ctcn: CompileTemplate(nullptr, &Recompiler::Compile_mtc2, PGXPFN(CPU_MTC2), TF_GTE_STALL | TF_READS_T | TF_PGXP_WITHOUT_CPU); break;
case CopCommonInstruction::mtcn: CompileTemplate(nullptr, &Recompiler::Compile_mtc2, PGXPFN(CPU_MTC2), TF_READS_T | TF_PGXP_WITHOUT_CPU); break;
case CopCommonInstruction::ctcn: CompileTemplate(nullptr, &Recompiler::Compile_mtc2, PGXPFN(CPU_MTC2), TF_READS_T | TF_PGXP_WITHOUT_CPU); break;
default: Compile_Fallback(); break;
}
}
@ -1314,7 +1314,7 @@ void CPU::Recompiler::Recompiler::CompileInstruction()
}
break;
case InstructionOp::lwc2: CompileLoadStoreTemplate(&Recompiler::Compile_lwc2, MemoryAccessSize::Word, false, false, TF_GTE_STALL | TF_READS_S | TF_LOAD_DELAY); break;
case InstructionOp::lwc2: CompileLoadStoreTemplate(&Recompiler::Compile_lwc2, MemoryAccessSize::Word, false, false, TF_READS_S | TF_LOAD_DELAY); break;
case InstructionOp::swc2: CompileLoadStoreTemplate(&Recompiler::Compile_swc2, MemoryAccessSize::Word, true, false, TF_GTE_STALL | TF_READS_S); SpecExec_swc2(); break;
// swc0/lwc0/cop1/cop3 are essentially no-ops