Macintosh-Tools/dingusppc
1
0
Fork 0
mirror of https://github.com/dingusdev/dingusppc.git synced 2024-06-10 13:29:42 +00:00
Code Issues Projects Releases Wiki Activity

ppcopcodes: fix cntlzw with __builtin_clz.

Browse Source 
The result of __builtin_clz is undefined when the source operand
is zero. Add a check for this case and handle it accordingly.
This commit is contained in:
Maxim Poliakovski 2020-12-07 14:26:55 +01:00
parent 5cba9c1dae
commit 99641b1b5e
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
cpu/ppc/ppcopcodes.cpp
View File

@ -516,15 +516,15 @@ void dppc_interpreter::ppc_neg() {
void dppc_interpreter::ppc_cntlzw() {
ppc_grab_regssa();
uint32_t lead = 0;
uint32_t lead;
uint32_t bit_check = ppc_result_d;
#ifdef USE_GCC_BUILTINS
lead = __builtin_clz(bit_check);
lead = !bit_check ? 32 : __builtin_clz(bit_check);
#elif defined USE_VS_BUILTINS
lead = __lzcnt(bit_check);
#else
for (uint32_t mask = 0x80000000UL; mask; lead++, mask >>= 1) {
for (uint32_t mask = 0x80000000UL, lead = 0; mask; lead++, mask >>= 1) {
if (bit_check & mask)
break;
}