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(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
This commit is contained in:
sudonim1@gmail.com 2011-10-11 13:03:24 +00:00
parent ae5ee1376c
commit 2e276316c6
1 changed files with 31 additions and 18 deletions
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49
pcsx2/R5900OpcodeImpl.cpp
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@ -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;
}
return result.SD[0];
ret = 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;
}