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Miroslav's patch to add run-time detection of operating system support for SSE/SSE2 instructions

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This commit is contained in:
Josh Coalson
2001-08-13 22:32:40 +00:00
parent 4ca5ec9940
commit a60231f436
3 changed files with 35 additions and 22 deletions
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37
src/libFLAC/cpu.c
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@@ -21,6 +21,12 @@
#include<stdlib.h>
#include<stdio.h>
#if !defined(FLAC__NO_ASM) && defined(FLAC__CPU_IA32) && defined(FLAC__HAS_NASM) && !defined(FLAC__SSE_OS) && !defined(NO_VFORK)
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#endif
const unsigned FLAC__CPUINFO_IA32_CPUID_CMOV = 0x00008000;
const unsigned FLAC__CPUINFO_IA32_CPUID_MMX = 0x00800000;
const unsigned FLAC__CPUINFO_IA32_CPUID_FXSR = 0x01000000;
@@ -44,17 +50,36 @@ void FLAC__cpu_info(FLAC__CPUInfo *info)
info->data.ia32.mmx = (cpuid & FLAC__CPUINFO_IA32_CPUID_MMX)? true : false;
info->data.ia32.fxsr = (cpuid & FLAC__CPUINFO_IA32_CPUID_FXSR)? true : false;
info->data.ia32.sse = (cpuid & FLAC__CPUINFO_IA32_CPUID_SSE)? true : false;
info->data.ia32.sse2 = (cpuid & FLAC__CPUINFO_IA32_CPUID_SSE2)? true : false; /* @@@ also need to check for operating system support? */
info->data.ia32.sse2 = (cpuid & FLAC__CPUINFO_IA32_CPUID_SSE2)? true : false;
#ifndef FLAC__SSE_OS
#ifndef NO_VFORK
if(info->data.ia32.sse == true || info->data.ia32.sse2 == true) {
int pid, status, sse;
pid = vfork();
if(!pid) {
FLAC__cpu_info_sse_test_asm_ia32();
exit(0);
}
sse = 0;
if(pid > 0) {
waitpid(pid, &status, 0);
if(WIFEXITED(status) && WEXITSTATUS(status) == 0)
sse = 1; /* there was normal exit, no SIGILL */
}
if(!sse)
info->data.ia32.sse = info->data.ia32.sse2 = false;
}
#else
/* we are assuming OS isn't supporting SSE */
info->data.ia32.sse = info->data.ia32.sse2 = false;
#endif
#endif
cpuid = FLAC__cpu_info_extended_amd_asm_ia32();
info->data.ia32._3dnow = (cpuid & FLAC__CPUINFO_IA32_CPUID_EXTENDED_AMD_3DNOW)? true : false;
info->data.ia32.ext3dnow = (cpuid & FLAC__CPUINFO_IA32_CPUID_EXTENDED_AMD_EXT3DNOW)? true : false;
info->data.ia32.extmmx = (cpuid & FLAC__CPUINFO_IA32_CPUID_EXTENDED_AMD_EXTMMX)? true : false;
#ifndef FLAC__SSE_OS
if(!FLAC__cpu_info_sse_os_asm_ia32()) /* this function currently always returns false */
info->data.ia32.fxsr = info->data.ia32.sse = info->data.ia32.sse2 = false;
#endif
}
#else
info->use_asm = false;

18
src/libFLAC/ia32/cpu_asm.nasm
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@@ -22,7 +22,7 @@
cglobal FLAC__cpu_info_asm_ia32
cglobal FLAC__cpu_info_extended_amd_asm_ia32
cglobal FLAC__cpu_info_sse_os_asm_ia32
cglobal FLAC__cpu_info_sse_test_asm_ia32
code_section
@@ -81,20 +81,8 @@ cident FLAC__cpu_info_extended_amd_asm_ia32
pop ebx
ret
;WATCHOUT - DO NOT call this function until you have verified CPU support of
; SSE by inspecting the return value from FLAC__cpu_info_asm_ia32
;NOTE - Since we're not in priv level 0 we can't just check CR4 bits 9 & 10,
; so right now we just assume there is no OS support. If you know
; how to write code to trap a #UD exception in nasm so we can implement
; this function correctly, let us know!
cident FLAC__cpu_info_sse_os_asm_ia32
push ebx
mov eax, 1
cpuid
mov eax, 0 ;we would like to 'move eax, cr4'
shr eax, 9
and eax, 3
cident FLAC__cpu_info_sse_test_asm_ia32
xorps xmm0, xmm0
pop ebx
ret
end

2
src/libFLAC/include/private/cpu.h
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@@ -63,7 +63,7 @@ void FLAC__cpu_info(FLAC__CPUInfo *info);
#ifdef FLAC__HAS_NASM
unsigned FLAC__cpu_info_asm_ia32();
unsigned FLAC__cpu_info_extended_amd_asm_ia32();
unsigned FLAC__cpu_info_sse_os_asm_ia32();
unsigned FLAC__cpu_info_sse_test_asm_ia32();
#endif
#endif
#endif