how to divide in MMX?

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3 total messages Started by ADS Mon, 09 Sep 2002 07:17

#201

Author: ADS
Date: Mon, 09 Sep 2002 07:17

22 lines
1337 bytes

Hello,

I have a code to do a addition in MMX.

how can I do a divide? I have not found a MMX equivalent.


type T16bit = array[0..3] of word;

procedure AdditionMMX(A,B : T16bit; var resultat : T16bit); register;
// adresse de A dans EAX
// adresse de B dans EDX
// adresse de resultat dans ECX
asm
  movq mm0,[EAX]
  paddw mm0,[EDX]
  movq [ECX],mm0
end;

thanks

Armindo

Re: how to divide in MMX?

#203

Author: Guido Gybels
Date: Mon, 09 Sep 2002 07:47

14 lines
1352 bytes

"ADS" <nospam@wanadoo.fr> wrote in message
news:3d7c4b0c$1@newsgroups.borland.com...
> how can I do a divide? I have not found a MMX equivalent.

The MMX set does not have a division instruction. You'll have to use
div/idiv. For division by a power of 2, use shifts.

Guido

--
Guido Gybels
http://www.optimalcode.com/Guido
(Disclaimer: all remarks made apply to Intel processors unless specified
otherwise)

Re: how to divide in MMX?

#205

Author: ADS
Date: Mon, 09 Sep 2002 09:07

14 lines
1359 bytes


>
> The MMX set does not have a division instruction. You'll have to use
> div/idiv. For division by a power of 2, use shifts.
>


So if I understand well I have to do the divide for each for words instead
of doing one operation (MMX advantage)?

thanks Guido

Armindo

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