From 2e276316c6adcbe879e1dd6d10845365b54e91d1 Mon Sep 17 00:00:00 2001
From: "sudonim1@gmail.com"
<sudonim1@gmail.com@96395faa-99c1-11dd-bbfe-3dabce05a288>
Date: Tue, 11 Oct 2011 13:03:24 +0000
Subject: [PATCH] (Patch from firnis) R5900int: As per MIPS documentation, do
not modify the destination register if an overflow exception occurs.
git-svn-id: http://pcsx2.googlecode.com/svn/trunk@4932 96395faa-99c1-11dd-bbfe-3dabce05a288
---
pcsx2/R5900OpcodeImpl.cpp | 49 +++++++++++++++++++++++++--------------
1 file changed, 31 insertions(+), 18 deletions(-)
diff --git a/pcsx2/R5900OpcodeImpl.cpp b/pcsx2/R5900OpcodeImpl.cpp
index 10b1180698..0b3f5c834a 100644
--- a/pcsx2/R5900OpcodeImpl.cpp
+++ b/pcsx2/R5900OpcodeImpl.cpp
@@ -24,7 +24,7 @@
#include "R5900Exceptions.h"
-static __fi s64 _add64_Overflow( s64 x, s64 y )
+static __fi bool _add64_Overflow( s64 x, s64 y, s64 &ret )
{
const s64 result = x + y;
@@ -32,18 +32,21 @@ static __fi s64 _add64_Overflow( s64 x, s64 y )
// which apparently works, and generates compact/fast x86 code too (the
// other method below is like 5-10 times slower).
- if( ((~(x^y))&(x^result)) < 0 )
+ if( ((~(x^y))&(x^result)) < 0 ) {
cpuException(0x30, cpuRegs.branch); // fixme: is 0x30 right for overflow??
+ return true;
+ }
// the not-as-fast style!
//if( ((x >= 0) && (y >= 0) && (result < 0)) ||
// ((x < 0) && (y < 0) && (result >= 0)) )
// cpuException(0x30, cpuRegs.branch);
- return result;
+ ret = result;
+ return false;
}
-static __fi s64 _add32_Overflow( s32 x, s32 y )
+static __fi bool _add32_Overflow( s32 x, s32 y, s64 &ret )
{
GPR_reg64 result; result.SD[0] = (s64)x + y;
@@ -52,10 +55,14 @@ static __fi s64 _add32_Overflow( s32 x, s32 y )
// against bit 31 (leftmost of the lower word).
// If bit32 != bit31 then we have an overflow.
- if( (result.UL[0]>>31) != (result.UL[1] & 1) )
+ if( (result.UL[0]>>31) != (result.UL[1] & 1) ) {
cpuException(0x30, cpuRegs.branch);
+ return true;
+ }
+
+ ret = result.SD[0];
- return result.SD[0];
+ return false;
}
@@ -266,8 +273,9 @@ void COP1_Unknown() { Console.Warning("Unknown FPU/COP1 opcode called"); }
// Rt = Rs + Im signed [exception on overflow]
void ADDI()
{
- s64 result = _add32_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], _Imm_ );
- if (!_Rt_) return;
+ s64 result;
+ bool overflow = _add32_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], _Imm_, result );
+ if (overflow || !_Rt_) return;
cpuRegs.GPR.r[_Rt_].SD[0] = result;
}
@@ -285,8 +293,9 @@ void ADDIU()
// of at 32 bits.
void DADDI()
{
- s64 result = _add64_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], _Imm_ );
- if (!_Rt_) return;
+ s64 result;
+ bool overflow = _add64_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], _Imm_, result );
+ if (overflow || !_Rt_) return;
cpuRegs.GPR.r[_Rt_].SD[0] = result;
}
@@ -312,31 +321,35 @@ void SLTIU() { if (!_Rt_) return; cpuRegs.GPR.r[_Rt_].UD[0] = (cpuRegs.GPR.r[
// Rd = Rs + Rt (Exception on Integer Overflow)
void ADD()
{
- s64 result = _add32_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], cpuRegs.GPR.r[_Rt_].SD[0] );
- if (!_Rd_) return;
+ s64 result;
+ bool overflow = _add32_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], cpuRegs.GPR.r[_Rt_].SD[0], result );
+ if (overflow || !_Rd_) return;
cpuRegs.GPR.r[_Rd_].SD[0] = result;
}
void DADD()
{
- s64 result = _add64_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], cpuRegs.GPR.r[_Rt_].SD[0] );
- if (!_Rd_) return;
+ s64 result;
+ bool overflow = _add64_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], cpuRegs.GPR.r[_Rt_].SD[0], result );
+ if (overflow || !_Rd_) return;
cpuRegs.GPR.r[_Rd_].SD[0] = result;
}
// Rd = Rs - Rt (Exception on Integer Overflow)
void SUB()
{
- s64 result = _add32_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], -cpuRegs.GPR.r[_Rt_].SD[0] );
- if (!_Rd_) return;
+ s64 result;
+ bool overflow = _add32_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], -cpuRegs.GPR.r[_Rt_].SD[0], result );
+ if (overflow || !_Rd_) return;
cpuRegs.GPR.r[_Rd_].SD[0] = result;
}
// Rd = Rs - Rt (Exception on Integer Overflow)
void DSUB()
{
- s64 result = _add64_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], -cpuRegs.GPR.r[_Rt_].SD[0] );
- if (!_Rd_) return;
+ s64 result;
+ bool overflow = _add64_Overflow( cpuRegs.GPR.r[_Rs_].SD[0], -cpuRegs.GPR.r[_Rt_].SD[0], result );
+ if (overflow || !_Rd_) return;
cpuRegs.GPR.r[_Rd_].SD[0] = result;
}