Mail Archives: djgpp/1997/08/20/03:03:22
From: | drumc96 AT aol DOT com (DrumC96)
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Newsgroups: | comp.os.msdos.djgpp
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Subject: | Moving data from video memory to main memory?
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Date: | 20 Aug 1997 02:53:07 GMT
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Lines: | 14
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Message-ID: | <19970820025301.WAA12569@ladder02.news.aol.com>
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NNTP-Posting-Host: | ladder02.news.aol.com
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Organization: | AOL http://www.aol.com
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To: | djgpp AT delorie DOT com
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DJ-Gateway: | from newsgroup comp.os.msdos.djgpp
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Hey everybody,
I'm trying to figure this out. I wrote a blit function for svga that
is pretty fast moving dwords at a time when possible. I made a copy
routine that is pretty much exactly the same except the bitmap destination
is edi and the source in video memory is esi (which is opposite for the
blit). I have a selector for video memory. The problem is, I can change es
in a function and have no problems, such as call movsd and having data
moved to video ram. When I change ds to my video memory selector, I can't
use movsd to copy data to main memory from video memory without a gpf.
Please explain why and how I can get around that. If you can understand
what I just tried to explain, then you probably have an answer. Im using
nasm so please if at all possible us intel syntax.
Sincerely,
DrumC96 AT aol DOT com
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