COP0: Preserve read only fields IC and DC in the config register

PCSX2 · Feb 24, 2021 · b088ee6 · b088ee6
1 parent 0a8ac3b
commit b088ee6
Show file tree

Hide file tree

Showing 3 changed files with 22 additions and 2 deletions.
diff --git a/pcsx2/COP0.cpp b/pcsx2/COP0.cpp
@@ -41,10 +41,14 @@ void __fastcall WriteCP0Status(u32 value) {
 	//DMA_LOG("COP0 Status write = 0x%08x", value);
 
 	cpuRegs.CP0.n.Status.val = value;
-    cpuUpdateOperationMode();
     cpuSetNextEventDelta(4);
 }
 
+void __fastcall WriteCP0Config(u32 value) {
+	// Protect the read-only ICacheSize (IC) and DataCacheSize (DC) bits
+	cpuRegs.CP0.n.Config = value & ~0xFC0;
+	cpuRegs.CP0.n.Config |= 0x440;
+}
 
 //////////////////////////////////////////////////////////////////////////////////////////
 // Performance Counters Update Stuff!
@@ -472,6 +476,10 @@ void MTC0()
 			WriteCP0Status(cpuRegs.GPR.r[_Rt_].UL[0]);
 		break;
 
+		case 16:
+			WriteCP0Config(cpuRegs.GPR.r[_Rt_].UL[0]);
+		break;
+
 		case 24:
 			COP0_LOG("MTC0 Breakpoint debug Registers code = %x", cpuRegs.code & 0x3FF);
 		break;

diff --git a/pcsx2/COP0.h b/pcsx2/COP0.h
@@ -17,6 +17,7 @@
 #define __COP0_H__
 
 extern void __fastcall WriteCP0Status(u32 value);
+extern void __fastcall WriteCP0Config(u32 value);
 extern void cpuUpdateOperationMode();
 extern void WriteTLB(int i);
 extern void UnmapTLB(int i);

diff --git a/pcsx2/x86/iCOP0.cpp b/pcsx2/x86/iCOP0.cpp
@@ -212,7 +212,12 @@ void recMTC0()
 		{
 			case 12:
 				iFlushCall(FLUSH_INTERPRETER);
-				xFastCall((void*)WriteCP0Status, g_cpuConstRegs[_Rt_].UL[0] );
+				xFastCall((void*)WriteCP0Status, g_cpuConstRegs[_Rt_].UL[0]);
+			break;
+
+			case 16:
+				iFlushCall(FLUSH_INTERPRETER);
+				xFastCall((void*)WriteCP0Config, g_cpuConstRegs[_Rt_].UL[0]);
 			break;
 
 			case 9:
@@ -265,6 +270,12 @@ void recMTC0()
 				xFastCall((void*)WriteCP0Status, ecx );
 			break;
 
+			case 16:
+				iFlushCall(FLUSH_INTERPRETER);
+				_eeMoveGPRtoR(ecx, _Rt_);
+				xFastCall((void*)WriteCP0Config, ecx);
+			break;
+
 			case 9:
 				xMOV(ecx, ptr[&cpuRegs.cycle]);
 				_eeMoveGPRtoM((uptr)&cpuRegs.CP0.r[9], _Rt_);