ShuriZma
/
pcsx2
mirror of https://github.com/PCSX2/pcsx2.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

iop: fix division overflow 

So far only on the const path because it is was easy (and free)
but it ought to be done on the recompiler too.
This commit is contained in:
Gregory Hainaut 2016-01-24 21:25:41 +01:00
parent 95be13bc4a
commit 8485a8c654
1 changed files with 13 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
pcsx2/x86/iR3000Atables.cpp
View File

@ -498,6 +498,19 @@ void rpsxDIV_const()
{
u32 lo, hi;
/*
* Normally, when 0x80000000(−2147483648), the signed minimum value, is divided by 0xFFFFFFFF(−1), the
* operation will result in overflow. However, in this instruction an overflow exception does not occur and the
* result will be as follows:
* Quotient: 0x80000000 (−2147483648), and remainder: 0x00000000 (0)
*/
// Of course x86 cpu does overflow !
if (g_psxConstRegs[_Rs_] == 0x80000000u && g_psxConstRegs[_Rt_] == 0xFFFFFFFFu) {
xMOV(ptr32[&psxRegs.GPR.n.hi], 0);
xMOV(ptr32[&psxRegs.GPR.n.lo], 0x80000000);
return;
}
if (g_psxConstRegs[_Rt_] != 0) {
lo = *(int*)&g_psxConstRegs[_Rs_] / *(int*)&g_psxConstRegs[_Rt_];
hi = *(int*)&g_psxConstRegs[_Rs_] % *(int*)&g_psxConstRegs[_Rt_];