Mail Archives: djgpp/1997/12/15/19:00:48
Michael Krause <mhkrause AT umich DOT edu> wrote in article
<3494C7D5 DOT 9305B6CA AT umich DOT edu>...
> You're writing to video memory. Video memory accesses can take from two
> to ten times longer than regular memory accesses. Try to point edi to
> something else instead, and time it.
>
Hi again!
Thanks for the answers, I got a fair speedup :-)
As you recommended me to, I did the graphic operation somewhere else, and
then copied to VRAM (rep movsl), and yes, it ran on about double speed.
Drawing a pixel (on my PC):
to VideoRam takes about 20 clocks
to a buffer takes about 9 clocks
The buffer is allocated this way: (the only way I know of)
char *mybuffer[64000];
Drawing to it still takes some time, and I like to do it even faster.
Can I allocate my buffer on a better way?
Could I possibly take advantage of the internal cache?
Thank you
-Lars
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