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PowerPC: Properly unset the overflow bit

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The OV bit is non-sticky. Therefore, after an overflow-enabled
instruction executes, if an overflow does *not* occur, then OV is
cleared. SO is sticky however, so it staying set in this case is
correct.
This commit is contained in:
Lioncash 2018-03-21 23:51:31 -04:00
parent 23bc50704a
commit e53fffeb90
2 changed files with 19 additions and 21 deletions
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38
Source/Core/Core/PowerPC/Interpreter/Interpreter_Integer.cpp
View file

@ -492,16 +492,12 @@ void Interpreter::addzex(UGeckoInstruction inst)
void Interpreter::divwx(UGeckoInstruction inst)
{
s32 a = rGPR[inst.RA];
s32 b = rGPR[inst.RB];
const s32 a = rGPR[inst.RA];
const s32 b = rGPR[inst.RB];
const bool overflow = b == 0 || ((u32)a == 0x80000000 && b == -1);
if (b == 0 || ((u32)a == 0x80000000 && b == -1))
if (overflow)
{
if (inst.OE)
{
SetXER_OV(true);
}
if (((u32)a & 0x80000000) && b == 0)
rGPR[inst.RD] = UINT32_MAX;
else
@ -512,22 +508,21 @@ void Interpreter::divwx(UGeckoInstruction inst)
rGPR[inst.RD] = (u32)(a / b);
}
if (inst.OE)
SetXER_OV(overflow);
if (inst.Rc)
Helper_UpdateCR0(rGPR[inst.RD]);
}
void Interpreter::divwux(UGeckoInstruction inst)
{
u32 a = rGPR[inst.RA];
u32 b = rGPR[inst.RB];
const u32 a = rGPR[inst.RA];
const u32 b = rGPR[inst.RB];
const bool overflow = b == 0;
if (b == 0)
if (overflow)
{
if (inst.OE)
{
SetXER_OV(true);
}
rGPR[inst.RD] = 0;
}
else
@ -535,6 +530,9 @@ void Interpreter::divwux(UGeckoInstruction inst)
rGPR[inst.RD] = a / b;
}
if (inst.OE)
SetXER_OV(overflow);
if (inst.Rc)
Helper_UpdateCR0(rGPR[inst.RD]);
}
@ -572,8 +570,8 @@ void Interpreter::mullwx(UGeckoInstruction inst)
rGPR[inst.RD] = static_cast<u32>(result);
if (inst.OE && (result < -0x80000000LL || result > 0x7FFFFFFFLL))
SetXER_OV(true);
if (inst.OE)
SetXER_OV(result < -0x80000000LL || result > 0x7FFFFFFFLL);
if (inst.Rc)
Helper_UpdateCR0(rGPR[inst.RD]);
@ -588,8 +586,8 @@ void Interpreter::negx(UGeckoInstruction inst)
if (inst.Rc)
Helper_UpdateCR0(rGPR[inst.RD]);
if (inst.OE && a == 0x80000000)
SetXER_OV(true);
if (inst.OE)
SetXER_OV(a == 0x80000000);
}
void Interpreter::subfx(UGeckoInstruction inst)

2
Source/Core/Core/PowerPC/PowerPC.h
View file

@ -434,7 +434,7 @@ inline u32 GetXER_OV()
inline void SetXER_OV(bool value)
{
PowerPC::ppcState.xer_so_ov |= static_cast<u32>(value);
PowerPC::ppcState.xer_so_ov = (PowerPC::ppcState.xer_so_ov & 0xFE) | static_cast<u32>(value);
SetXER_SO(value);
}