MMX instruction usefull?

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7 total messages Started by ADS Wed, 04 Sep 2002 14:17

#386

Author: ADS
Date: Wed, 04 Sep 2002 14:17

42 lines
1834 bytes

Hello,

I have to apply the some Mathematical function to 3 variables and I have
heard that with MMX we can do at the same time multiple functions :

Different cases :

here Value is an integer,

and CMY               : array[0..9] of cmsCMY;  where

 cmsCMY = packed record
    C, M, Y: Double
  end;

addition and multiplication

CMY[J].C := CMY[J].C + CMY[k].C * Value;
CMY[J].M := CMY[J].M + CMY[k].M * Value;
CMY[J].Y := CMY[J].Y + CMY[k].Y * Value;

division

CMY[J].C := CMY[k].C  /  Value;
CMY[J].M := CMY[k].M  /  Value;
CMY[J].Y := CMY[k].Y / Value;

multiplication

CMY[J].C := CMY[k].C  *  Value;
CMY[J].M := CMY[k].M  *  Value;
CMY[J].Y := CMY[k].Y * Value;


if the operation can be done in one step instead of three it could improve
speed a lot I think.

any idea?

thanks

Armindo

Re: MMX instruction usefull?

#390

Author: Andrew Rybenkov
Date: Wed, 04 Sep 2002 15:03

11 lines
1316 bytes

Not with MMX. For doubles you need SSE2 (PIII Tualatin or P4, (Tualatin is faster, btw)).
OTOH, for most of color manipulations singles are more than enough (IMHO).
So it would be SSE (any PIII and P4, naturally, too).

--
Andrew Rybenkov.

create labels, logos, image lists
for your programs and websites with
  "Imagizer: Click and Get It",
  http://www.geocities.com/arybenkov/imagizer/

Re: MMX instruction usefull?

#389

Author: Robert Lee
Date: Wed, 04 Sep 2002 15:14

19 lines
1426 bytes

ADS wrote:

> Hello,
>
> I have to apply the some Mathematical function to 3 variables and I have
> heard that with MMX we can do at the same time multiple functions :

>  cmsCMY = packed record
>     C, M, Y: Double
>   end;

MMX doesn't do floating point...and SSE and 3dNow can only do simultaneous
math on singles IIRC.  In short, you have to get all the way to SSE2 before
you can really do what you want to do.

--
Bob Lee
High Performance Delphi - http://www.optimalcode.com/

Re: MMX instruction usefull?

#392

Author: ADS
Date: Wed, 04 Sep 2002 15:26

8 lines
1112 bytes

Thanks Andrew and Robert for your reply,

So if I decide to do it in SSE and 3DNow, what would instruction should I
use?

thanks

Armindo

Re: MMX instruction usefull?

#391

Author: ADS
Date: Wed, 04 Sep 2002 15:26

9 lines
1194 bytes


>
> So if I decide to do it in SSE and 3DNow, what would instruction should I
> use?
>


in this case I will use singles of course

Re: MMX instruction usefull?

#393

Author: Guido Gybels
Date: Wed, 04 Sep 2002 17:23

17 lines
1534 bytes

"ADS" <nospam@wanadoo.fr> wrote in message
news:3d76260a@newsgroups.borland.com...
> So if I decide to do it in SSE and 3DNow, what would instruction should I
> use?

These are the SSE arithmetic instructions for addition, division,
multiplication and substraction:

ADD?S, DIV?S, MUL?S, SUB?S

Their SSE2 double equivalents are similar:

ADD?D, DIV?D, MUL?D, SUB?D

The ? is either P for packed doubles or S for the scalar version.

Guido

Re: MMX instruction usefull?

#51

Author: ADS
Date: Wed, 04 Sep 2002 17:46

16 lines
1439 bytes

Thanks Guido
>
> These are the SSE arithmetic instructions for addition, division,
> multiplication and substraction:
>
> ADD?S, DIV?S, MUL?S, SUB?S
>
> Their SSE2 double equivalents are similar:
>
> ADD?D, DIV?D, MUL?D, SUB?D
>
> The ? is either P for packed doubles or S for the scalar version.
>
> Guido
>
>

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