From: Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Graphics under DJGPP V2.01
Date: Thu, 12 Dec 1996 20:19:53 +0000
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Message-ID: <+I7MVFApjGsyEwWj@talula.demon.co.uk>
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To: djgpp AT delorie DOT com
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Thomas Harte writes:
>   for(temp=0;temp<64000;temp++)
>     {
>      _farpokeb(_dos_ds, 0xA0000 + temp, doublebuffer[temp]);
>      doublebuffer[temp]=background[temp];
>     }    
>
>       Which faster methods can I use to copy the contents of an
> integer into the video ram, starting at 0xA0000 ?

Try dosmemput(), or dosmemputl(). These are described in the info docs,
and should use a 'rep ; movsl' instruction which is about as fast as it
possible to do the transfer.

>       How would I switch graphic modes (to and from mode 13h) under DJGPP ? 

The same way as in real mode: call BIOS interrupt 0x10. The only
difference is that you have to use a DPMI function to call the BIOS, eg:

     __dpmi_regs r;
     r.x.ax = 0x13;
     __dpmi_int(0x10, &r);

For some excellent introductory tutorials to graphics coding under
djgpp, take a look at Brennan's pages:

        http://www.rt66.com/~brennan/djgpp/

/*
 *  Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
 *  Ghoti: 'gh' as in 'enough', 'o' as in 'women', and 'ti' as in 'nation'.
 */