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libFLAC/cpu.c : Bundle of minor fixes.

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Includes:

* Replace 'CALLBACK' with 'WINAPI' because the signature of an unhandled
  exception filter uses 'WINAPI'.
* Improvements to OS SSE testing code.
* Improvements to GCC asm code.
* Comment fixes.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
This commit is contained in:
Erik de Castro Lopo
2014-03-27 19:30:43 +11:00
parent 1e0856664d
commit ac940e4175
1 changed files with 12 additions and 11 deletions
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23
src/libFLAC/cpu.c
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@@ -142,7 +142,7 @@ static const unsigned FLAC__CPUINFO_IA32_CPUID_EXTENDED_AMD_EXTMMX = 0x00400000;
# define USE_TRY_CATCH_FLAVOR /* sigill_handler flavor resulted in several crash reports on win32 */
# ifdef USE_TRY_CATCH_FLAVOR
# else
LONG CALLBACK sigill_handler_sse_os(EXCEPTION_POINTERS *ep)
LONG WINAPI sigill_handler_sse_os(EXCEPTION_POINTERS *ep)
{
if(ep->ExceptionRecord->ExceptionCode == EXCEPTION_ILLEGAL_INSTRUCTION) {
ep->ContextRecord->Eip += 3 + 3 + 6;
@@ -245,9 +245,9 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
#endif
/*
* now have to check for OS support of SSE/SSE2
* now have to check for OS support of SSE instructions
*/
if(info->ia32.fxsr || info->ia32.sse || info->ia32.sse2) {
if(info->ia32.sse) {
#if defined FLAC__NO_SSE_OS
/* assume user knows better than us; turn it off */
info->ia32.fxsr = info->ia32.sse = info->ia32.sse2 = info->ia32.sse3 = info->ia32.ssse3 = info->ia32.sse41 = info->ia32.sse42 = false;
@@ -292,7 +292,6 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
/* http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html */
/* see sigill_handler_sse_os() for an explanation of the following: */
asm volatile (
"xorl %0,%0\n\t" /* for some reason, still need to do this to clear 'sse' var */
"xorps %%xmm0,%%xmm0\n\t" /* will cause SIGILL if unsupported by OS */
"incl %0\n\t" /* SIGILL handler will jump over this */
/* landing zone */
@@ -306,7 +305,7 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
"nop\n\t"
"nop" /* SIGILL jump lands here if "inc" is 1 byte */
: "=r"(sse)
: "r"(sse)
: "0"(sse)
);
sigaction(SIGILL, &sigill_save, NULL);
@@ -327,11 +326,12 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
}
# else
int sse = 0;
/* From MSDN: SetUnhandledExceptionFilter replaces the existing top-level exception filter for all threads in the calling process */
/* So sigill_handler_sse_os() is process-wide and affects other threads as well (not a good thing for a library in a multi-threaded process) */
LPTOP_LEVEL_EXCEPTION_FILTER save = SetUnhandledExceptionFilter(sigill_handler_sse_os);
/* see GCC version above for explanation */
/* http://msdn2.microsoft.com/en-us/library/4ks26t93.aspx */
/* http://www.codeproject.com/cpp/gccasm.asp */
/* http://www.hick.org/~mmiller/msvc_inline_asm.html */
/* http://msdn.microsoft.com/en-us/library/4ks26t93.aspx */
/* http://www.codeproject.com/Articles/5267/Inline-Assembly-in-GCC-Vs-VC */
__asm {
xorps xmm0,xmm0
inc sse
@@ -354,7 +354,7 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
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) {
if (info->ia32.fxsr) {
struct {
FLAC__uint32 buff[128];
} __attribute__((aligned(16))) fxsr;
@@ -403,10 +403,11 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
info->ia32.fxsr = info->ia32.sse = info->ia32.sse2 = info->ia32.sse3 = info->ia32.ssse3 = info->ia32.sse41 = info->ia32.sse42 = false;
#endif
#ifdef DEBUG
fprintf(stderr, " SSE OS sup . %c\n", info->ia32.sse ? 'Y' : 'n');
fprintf(stderr, " SSE OS sup . %c\n", info->ia32.sse ? 'Y' : 'n');
#endif
}
else /* info->ia32.sse == false */
info->ia32.fxsr = info->ia32.sse = info->ia32.sse2 = info->ia32.sse3 = info->ia32.ssse3 = info->ia32.sse41 = info->ia32.sse42 = false;
}
#else
info->use_asm = false;