From 96787690c7e01120cc3575d2190d0ffe27372cc1 Mon Sep 17 00:00:00 2001
From: zilmar <zilmar@pj64-emu.com>
Date: Mon, 20 Mar 2023 12:09:06 +1030
Subject: [PATCH] Core: Fix CoprocessorUnitNumber on exception

---
 .../N64System/Mips/Register.cpp               | 23 +++++++++----------
 .../Project64-core/N64System/Mips/Register.h  |  4 +++-
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/Source/Project64-core/N64System/Mips/Register.cpp b/Source/Project64-core/N64System/Mips/Register.cpp
index 4b41ce391..1c82fa055 100644
--- a/Source/Project64-core/N64System/Mips/Register.cpp
+++ b/Source/Project64-core/N64System/Mips/Register.cpp
@@ -553,6 +553,7 @@ void CRegisters::DoAddressError(bool DelaySlot, uint64_t BadVaddr, bool FromRead
     {
         CAUSE_REGISTER.ExceptionCode = EXC_WADE;
     }
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     BAD_VADDR_REGISTER = BadVaddr;
     CONTEXT_REGISTER.BadVPN2 = BadVaddr >> 13;
     XCONTEXT_REGISTER.BadVPN2 = BadVaddr >> 13;
@@ -607,6 +608,7 @@ void CRegisters::DoBreakException(bool DelaySlot)
     }
 
     CAUSE_REGISTER.ExceptionCode = EXC_BREAK;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     if (DelaySlot)
     {
         CAUSE_REGISTER.BranchDelay = 1;
@@ -624,6 +626,7 @@ void CRegisters::DoBreakException(bool DelaySlot)
 void CRegisters::DoFloatingPointException(bool DelaySlot)
 {
     CAUSE_REGISTER.ExceptionCode = EXC_FPE;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     if (DelaySlot)
     {
         EPC_REGISTER = (int64_t)((int32_t)m_PROGRAM_COUNTER - 4);
@@ -641,6 +644,7 @@ void CRegisters::DoFloatingPointException(bool DelaySlot)
 void CRegisters::DoTrapException(bool DelaySlot)
 {
     CAUSE_REGISTER.ExceptionCode = EXC_TRAP;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     if (DelaySlot)
     {
         EPC_REGISTER = (int64_t)((int32_t)m_PROGRAM_COUNTER - 4);
@@ -669,18 +673,7 @@ void CRegisters::DoCopUnusableException(bool DelaySlot, int32_t Coprocessor)
     }
 
     CAUSE_REGISTER.ExceptionCode = EXC_CPU;
-    if (Coprocessor == 1)
-    {
-        CAUSE_REGISTER.Value |= 0x10000000;
-    }
-    else if (Coprocessor == 2)
-    {
-        CAUSE_REGISTER.Value |= 0x20000000;
-    }
-    else if (Coprocessor == 3)
-    {
-        CAUSE_REGISTER.Value |= 0x30000000;
-    }
+    CAUSE_REGISTER.CoprocessorUnitNumber = Coprocessor;
     if (DelaySlot)
     {
         CAUSE_REGISTER.BranchDelay = 1;
@@ -718,6 +711,7 @@ bool CRegisters::DoIntrException(bool DelaySlot)
     }
 
     CAUSE_REGISTER.ExceptionCode = EXC_INT;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
 
     if (DelaySlot)
     {
@@ -738,6 +732,7 @@ bool CRegisters::DoIntrException(bool DelaySlot)
 void CRegisters::DoIllegalInstructionException(bool DelaySlot)
 {
     CAUSE_REGISTER.ExceptionCode = EXC_II;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     if (DelaySlot)
     {
         CAUSE_REGISTER.BranchDelay = 1;
@@ -755,6 +750,7 @@ void CRegisters::DoIllegalInstructionException(bool DelaySlot)
 void CRegisters::DoOverflowException(bool DelaySlot)
 {
     CAUSE_REGISTER.ExceptionCode = EXC_OV;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     if (DelaySlot)
     {
         CAUSE_REGISTER.BranchDelay = 1;
@@ -772,6 +768,7 @@ void CRegisters::DoOverflowException(bool DelaySlot)
 void CRegisters::DoTLBReadMiss(bool DelaySlot, uint64_t BadVaddr)
 {
     CAUSE_REGISTER.ExceptionCode = EXC_RMISS;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     BAD_VADDR_REGISTER = BadVaddr;
     CONTEXT_REGISTER.BadVPN2 = BadVaddr >> 13;
     ENTRYHI_REGISTER = (BadVaddr & 0xFFFFE000);
@@ -810,6 +807,7 @@ void CRegisters::DoTLBReadMiss(bool DelaySlot, uint64_t BadVaddr)
 void CRegisters::DoTLBWriteMiss(bool DelaySlot, uint64_t BadVaddr)
 {
     CAUSE_REGISTER.ExceptionCode = EXC_WMISS;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     BAD_VADDR_REGISTER = BadVaddr;
     CONTEXT_REGISTER.BadVPN2 = BadVaddr >> 13;
     ENTRYHI_REGISTER = (BadVaddr & 0xFFFFE000);
@@ -860,6 +858,7 @@ void CRegisters::DoSysCallException(bool DelaySlot)
     }
 
     CAUSE_REGISTER.ExceptionCode = EXC_SYSCALL;
+    CAUSE_REGISTER.CoprocessorUnitNumber = 0;
     if (DelaySlot)
     {
         CAUSE_REGISTER.BranchDelay = 1;
diff --git a/Source/Project64-core/N64System/Mips/Register.h b/Source/Project64-core/N64System/Mips/Register.h
index 4aa20f939..0aaffd0f8 100644
--- a/Source/Project64-core/N64System/Mips/Register.h
+++ b/Source/Project64-core/N64System/Mips/Register.h
@@ -29,7 +29,9 @@ union COP0Cause
         unsigned ExceptionCode : 5;
         unsigned : 1;
         unsigned PendingInterrupts : 8;
-        unsigned : 15;
+        unsigned : 12;        
+        unsigned CoprocessorUnitNumber : 2;
+        unsigned : 1;
         unsigned BranchDelay : 1;
     };
 };