mirrors/flac
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

libFLAC/cpu.c: Eliminate a branch in cpu_info_x86

Browse Source 
Inverting all the if statements allows us to move the common code of
setting all the registers to zero outside the #if statement.
This commit is contained in:
Julian Calaby 2016-06-27 22:37:45 +10:00 committed by Erik de Castro Lopo
parent e58a6e7549
commit 79ca23ece3
1 changed files with 9 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/libFLAC/cpu.c
View File

@ -457,25 +457,23 @@ void FLAC__cpu_info_x86(FLAC__uint32 level, FLAC__uint32 *eax, FLAC__uint32 *ebx
int cpuinfo[4];
int ext = level & 0x80000000;
__cpuid(cpuinfo, ext);
if((unsigned)cpuinfo[0] < level) {
*eax = *ebx = *ecx = *edx = 0;
if((unsigned)cpuinfo[0] >= level) {
cpu_id_ex (cpuinfo, ext);
*eax = cpuinfo[0]; *ebx = cpuinfo[1]; *ecx = cpuinfo[2]; *edx = cpuinfo[3];
return;
}
cpu_id_ex (cpuinfo, ext);
*eax = cpuinfo[0]; *ebx = cpuinfo[1]; *ecx = cpuinfo[2]; *edx = cpuinfo[3];
#elif defined __GNUC__ && defined HAVE_CPUID_H
FLAC__uint32 ext = level & 0x80000000;
__cpuid(ext, *eax, *ebx, *ecx, *edx);
if (*eax < level) {
*eax = *ebx = *ecx = *edx = 0;
if (*eax >= level) {
__cpuid_count(level, 0, *eax, *ebx, *ecx, *edx);
return;
}
__cpuid_count(level, 0, *eax, *ebx, *ecx, *edx);
#else
*eax = *ebx = *ecx = *edx = 0;
#endif
*eax = *ebx = *ecx = *edx = 0;
}
#endif /* (FLAC__CPU_IA32 || FLAC__CPU_X86_64) && FLAC__HAS_X86INTRIN */