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thecf

Joined: 23 Dec 2006
Posts: 23

thecf 24 Dec 2006, 14:17

how do i check for mmx support?

24 Dec 2006, 14:17

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 24 Dec 2006, 14:24

Code:

; http://www.sandpile.org/ia32/cpuid.htm
mmx_detect: ; Returns 1 if MMX present, 0 otherwise
mov eax, 1
cpuid
test edx, 800000h
setnz al
ret

I'm assuming that CPU supports CPUID (support starts from late 486 CPUs)

24 Dec 2006, 14:24

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 24 Dec 2006, 14:29

This one checks for CPUID presence first

Code:

mmx_detect: ; Returns 1 if MMX present, 0 otherwise 
  pushf
  pop   eax

  pushf
  xor   byte [esp+2], $20
  popf

  pushf
  pop   edx
  cmp   eax, edx
  je    .return

  mov eax, 1 
  cpuid 
  test edx, 800000h 
.return:
  setnz al 
  ret

24 Dec 2006, 14:29

thecf

Joined: 23 Dec 2006
Posts: 23

thecf 29 Dec 2006, 13:20

thanks guys it works fine

29 Dec 2006, 13:20

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