From:	ajps AT mail DOT telepac DOT pt (aperes)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Assembly routine
Date:	Sat, 03 Jul 1999 08:36:01 GMT
Lines:	73
Message-ID:	<377dc388.147090@news.telepac.pt>
References:	<377b163a DOT 2813653 AT news DOT telepac DOT pt> <930893937 DOT 855103 AT kyle DOT inet DOT net DOT nz>
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To:	djgpp AT delorie DOT com
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On Fri, 2 Jul 1999 17:12:22 +1200, "David Mitchell"
<dmitchell AT inet DOT net DOT nz> wrote:

>aperes wrote in message <377b163a DOT 2813653 AT news DOT telepac DOT pt>...
>>
>>Please help me!
>>
>>I'm trying to write a routine that transfers the contents of a buffer
>>to video memory. This is my routine:
>>
>>    FlipAsm(_my_ds(), (int) virtual_screen);
>
>you want to call it by:
>    FlipAsm(_my_ds(), &virtual_screen);
>
>also:
>>  asm("
>>       MOVW %0, %%ES  /* ES= video (%0)  */
>>       MOVW %1, %%DS  /* DS= buffer (%1) = segmento dados */
>>
>>       MOVL $0xA0000, %%EAX
>>       MOVL %%EAX, %%EDI /* EDI = Ax0000, ES:DI
>>       MOVL %2, %%EAX
>>       MOVL %%EAX, %%ESI /* ESI = source, DS:SI */
>
>
>This code is wrong.  You are moving the Data segment to ES, whereas you want
>to move 0x0a000 to ES, and xorw %%si, %%si
>Then it should work.  You don't need the video variable.
>
>David
>
>

Thanks for your help, David but didn't worked or maybe i didn't not
understood your explication.
Put diferentely, what i want is use the assembly instruction MOVS to
move the data in DS:SI (my virtual screen) onto ES:DI (my destiny, the
video memory). If in my C program my virtual screen is, for example,
VS[64000] how i set up  DS, SI to pointer to VS and ES, DI to pointer
to video memory?

main() {

unsigned char VS[64000];
             ....
             ....

       flip(VS) ;
          
             ....

}

void flip(char *buffer) 
{
      .....
/* how to set up DS:SI to pointer to  buffer? */
/* how to set up ES:DI to pointer to video memory? */

MOVW $32000, %%CX 
REP
MOVW

    ...
}

Excuse me my poor english and thanks for your help and
patient.

APeres

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