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

Fix division edge cases and prevent crash

This commit is contained in:
Kellan Clark 2022-10-23 20:22:21 -04:00
parent 739f3162d5
commit b5b7f29255
1 changed files with 15 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
desmume/src/MMU.cpp
View File

@ -1068,7 +1068,6 @@ static void execsqrt() {
} }
static void execdiv() { static void execdiv() {
s64 num,den; s64 num,den;
s64 res,mod; s64 res,mod;
u8 mode = MMU_new.div.mode; u8 mode = MMU_new.div.mode;
@ -1096,15 +1095,29 @@ static void execdiv() {
break; break;
} }
if(den==0) if(den == 0)
{ {
res = ((num < 0) ? 1 : -1); res = ((num < 0) ? 1 : -1);
mod = num; mod = num;
// when the result is 32bits, the upper 32bits of the sign-extended result are inverted
if (mode == 0)
res ^= 0xFFFFFFFF00000000;
// the DIV0 flag in DIVCNT is set only if the full 64bit DIV_DENOM value is zero, even in 32bit mode // the DIV0 flag in DIVCNT is set only if the full 64bit DIV_DENOM value is zero, even in 32bit mode
if ((u64)T1ReadQuad(MMU.ARM9_REG, 0x298) == 0) if ((u64)T1ReadQuad(MMU.ARM9_REG, 0x298) == 0)
MMU_new.div.div0 = 1; MMU_new.div.div0 = 1;
} }
else if((mode != 0) && (num == 0x8000000000000000) && (den == -1))
{
res = 0x8000000000000000;
mod = 0;
}
else if((mode == 0) && (num == (s64) (s32) 0x80000000) && (den == -1))
{
res = 0x80000000;
mod = 0;
}
else else
{ {
res = num / den; res = num / den;