From:	"Thomas Harte" <T DOT Harte AT btinternet DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Graphics under DJGPP V2.01
Date:	11 Dec 1996 18:37:28 GMT
Organization:	Dell Computer Corporation
Lines:	26
Message-ID:	<01bbe78f$57f16cc0$LocalHost@default>
NNTP-Posting-Host:	host-73-37-212.btinternet.com
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

	I am fairly new to this compiler, but so far I have liked everything I
have seen. My previous C compiler was a Borland DOS version, so I am very
new to protected mode. As such, I am having trouble with graphics. At the
minute (in DJGPP) I access the VGA board using the code :-

   for(temp=0;temp<64000;temp++)
     {
      _farpokeb(_dos_ds, 0xA0000 + temp, doublebuffer[temp]);
      doublebuffer[temp]=background[temp];
     }    

which, as I'm sure you can imagine is VERY slow, in that it copies each
pixel individually. Anyway, my question is :-

	Which faster methods can I use to copy the contents of an integer into the
video ram, starting at 0xA0000 ?

Also :-

	How would I switch graphic modes (to and from mode 13h) under DJGPP ? (at
the moment I have code from the old compiler which changes modes running
before and after the new programs in a batch file) 

Thanks,

		-Thomas

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