mirrors
/
flac
mirror of https://github.com/xiph/flac
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

libFLAC/cpu.c : Detect SSE correctly on Windows when compiling with MinGW. 

Patch-from: lvqcl <lvqcl.mail@gmail.com>
This commit is contained in:
Erik de Castro Lopo 2014-03-14 15:40:53 +11:00
parent 47bd9964fa
commit 99d5154f43
1 changed files with 66 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
src/libFLAC/cpu.c
View File

@ -151,6 +151,23 @@ static const unsigned FLAC__CPUINFO_IA32_CPUID_EXTENDED_AMD_EXTMMX = 0x00400000;
return EXCEPTION_CONTINUE_SEARCH;
}
# endif
# elif defined(_WIN32) && defined(__GNUC__)
# undef USE_FXSR_FLAVOR
# ifdef USE_FXSR_FLAVOR
/* not guaranteed to work on some unknown future Intel CPUs */
# else
/* exception handler is process-wide; not good for a library */
# include <windows.h>
LONG WINAPI sigill_handler_sse_os(EXCEPTION_POINTERS *ep); /* to suppress GCC warning */
LONG WINAPI sigill_handler_sse_os(EXCEPTION_POINTERS *ep)
{
if(ep->ExceptionRecord->ExceptionCode == EXCEPTION_ILLEGAL_INSTRUCTION) {
ep->ContextRecord->Eip += 3 + 3 + 6;
return EXCEPTION_CONTINUE_EXECUTION;
}
return EXCEPTION_CONTINUE_SEARCH;
}
# endif
# endif
#endif
@ -332,6 +349,55 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
if(!sse)
info->ia32.fxsr = info->ia32.sse = info->ia32.sse2 = info->ia32.sse3 = info->ia32.ssse3 = info->ia32.sse41 = info->ia32.sse42 = false;
# endif
#elif defined(_WIN32) && defined(__GNUC__)
# ifdef USE_FXSR_FLAVOR
int sse = 0;
/* Based on the idea described in Agner Fog's manual "Optimizing subroutines in assembly language" */
/* In theory, not guaranteed to detect lack of OS SSE support on some future Intel CPUs, but in practice works (see the aforementioned manual) */
if (info->ia32.fxsr && info->ia32.sse) {
struct {
FLAC__uint32 buff[128];
} __attribute__((aligned(16))) fxsr;
FLAC__uint32 old_val, new_val;
asm volatile ("fxsave %0" : "=m" (fxsr) : "m" (fxsr));
old_val = fxsr.buff[50];
fxsr.buff[50] ^= 0x0013c0de; /* change value in the buffer */
asm volatile ("fxrstor %0" : "=m" (fxsr) : "m" (fxsr)); /* try to change SSE register */
fxsr.buff[50] = old_val; /* restore old value in the buffer */
asm volatile ("fxsave %0 " : "=m" (fxsr) : "m" (fxsr)); /* old value will be overwritten if SSE register was changed */
new_val = fxsr.buff[50]; /* == old_val if FXRSTOR didn't change SSE register and (old_val ^ 0x0013c0de) otherwise */
fxsr.buff[50] = old_val; /* again restore old value in the buffer */
asm volatile ("fxrstor %0" : "=m" (fxsr) : "m" (fxsr)); /* restore old values of registers */
if ((old_val^new_val) == 0x0013c0de)
sse = 1;
}
if(!sse)
info->ia32.fxsr = info->ia32.sse = info->ia32.sse2 = info->ia32.sse3 = info->ia32.ssse3 = info->ia32.sse41 = info->ia32.sse42 = false;
# else
int sse = 0;
LPTOP_LEVEL_EXCEPTION_FILTER save = SetUnhandledExceptionFilter(sigill_handler_sse_os);
/* see MSVC version above for explanation */
asm volatile (
"xorps %%xmm0,%%xmm0\n\t"
"incl %0\n\t"
"nop\n\t" /* SIGILL jump lands here if "inc" is 9 bytes */
"nop\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
"nop" /* SIGILL jump lands here if "inc" is 1 byte */
: "=r"(sse)
: "0"(sse)
);
SetUnhandledExceptionFilter(save);
if(!sse)
info->ia32.fxsr = info->ia32.sse = info->ia32.sse2 = info->ia32.sse3 = info->ia32.ssse3 = info->ia32.sse41 = info->ia32.sse42 = false;
# endif
#else
/* no way to test, disable to be safe */
info->ia32.fxsr = info->ia32.sse = info->ia32.sse2 = info->ia32.sse3 = info->ia32.ssse3 = info->ia32.sse41 = info->ia32.sse42 = false;