cpu support code
#ifndef CPU_SUPPORT_H
#define CPU_SUPPORT_H
#define CPU_SUPPORTS_CPUID (0x00000001L)
#define CPU_SUPPORTS_FPU (0x00000002L)
#define CPU_SUPPORTS_MMX (0x00000004L)
#define CPU_SUPPORTS_INTEGER_SSE (0x00000008L)
#define CPU_SUPPORTS_SSE (0x00000010L)
#define CPU_SUPPORTS_SSE2 (0x00000020L)
#define CPU_SUPPORTS_3DNOW (0x00000040L)
#define CPU_SUPPORTS_3DNOW_EXT (0x00000080L)
long CPUGetSupportedExtensions();
#endif
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#include <wtypes.h>
#include <winnt.h>
#include "cpusupport.h"
static long g_lCPUExtensionsAvailable;
// This is ridiculous ???
static long CPUCheckForSSESupport() {
__try
{
// __asm andps xmm0,xmm0
__asm _emit 0x0f
__asm _emit 0x54
__asm _emit 0xc0
}
__except(EXCEPTION_EXECUTE_HANDLER)
{
// The operating system does not recognize andps. Reset them.
if (_exception_code() == STATUS_ILLEGAL_INSTRUCTION)
g_lCPUExtensionsAvailable &= ~(CPU_SUPPORTS_SSE|CPU_SUPPORTS_SSE2);
}
return g_lCPUExtensionsAvailable;
}
long __declspec(naked) CPUGetSupportedExtensions() {
__asm {
push ebp
push edi
push esi
push ebx
xor ebp,ebp ;cpu flags - if we don't have CPUID, we probably
;won't want to try FPU optimizations.
;check for CPUID.
pushfd ;flags -> EAX
pop eax
or eax,00200000h ;set the ID bit
push eax ;EAX -> flags
popfd
pushfd ;flags -> EAX
pop eax
and eax,00200000h ;ID bit set?
jz done ;nope...
;CPUID exists, check for features register.
mov ebp,00000003h
xor eax,eax
cpuid
or eax,eax
jz done ;no features register?!?
;features register exists, look for MMX, SSE, SSE2.
mov eax,1
cpuid
mov ebx,edx
and ebx,00800000h ;MMX is bit 23
shr ebx,21
or ebp,ebx ;set bit 2 if MMX exists
mov ebx,edx
and edx,02000000h ;SSE is bit 25
shr edx,25
neg edx
and edx,00000018h ;set bits 3 and 4 if SSE exists
or ebp,edx
and ebx,04000000h ;SSE2 is bit 26
shr ebx,21
and ebx,00000020h ;set bit 5
or ebp,ebx
;check for vendor feature register (K6/Athlon).
mov eax,80000000h
cpuid
mov ecx,80000001h
cmp eax,ecx
jb done
;vendor feature register exists, look for 3DNow! and Athlon extensions
mov eax,ecx
cpuid
mov eax,edx
and edx,80000000h ;3DNow! is bit 31
shr edx,25
or ebp,edx ;set bit 6
mov edx,eax
and eax,40000000h ;3DNow!2 is bit 30
shr eax,23
or ebp,eax ;set bit 7
and edx,00400000h ;AMD MMX extensions (integer SSE) is bit 22
shr edx,19
or ebp,edx
done:
mov eax,ebp
mov g_lCPUExtensionsAvailable, ebp
;Full SSE and SSE-2 require OS support for the xmm* registers.
test eax,00000030h
jz nocheck
call CPUCheckForSSESupport
nocheck:
pop ebx
pop esi
pop edi
pop ebp
ret
}
}
