Xref:	news2.mv.net comp.os.msdos.djgpp:4511
From:	leathm AT gbrmpa DOT gov DOT au (Leath Muller)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Are near pointers worth it?
Date:	3 Jun 1996 01:46:15 GMT
Lines:	22
Message-ID:	<4otg57$qh1@news.mel.aone.net.au>
References:	<Pine DOT SGI DOT 3 DOT 91 DOT 960602091339 DOT 1316A-100000 AT sgi16 DOT york DOT ac DOT uk>
NNTP-Posting-Host:	solwarra.gbrmpa.gov.au
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

>> I have managed to get graphics to work in DJGPP by doing all the work
>> on an off screen buffer, and the copying the whole thing to VGA memory
>> in one go. So I only have to set the selector once, and the use a rep
>> movsb command. I have also made this work with SVGA graphics, VESA 1.2
>> and VESA 2 linear frame buffers. If I were to use near pointers would
>> it make it any faster?

>I think not. I got about a 5% speedup of my putpixel() function from 
>using near pointers, and that is the absolute worst case becuase it 
>involves a segment load per pixel. If you are just setting the selector 
>once for any more significant drawing tasks, the overhead is so small as 
>to be totally insignificant.

Ummm...just one question about this... :)

If you are running a 640x480 screen, and you want to run at 30fps, isnt
this 9,216,000 pixels? A saving of 5% in this case is about 460,800 pixels.

I might be being picky, but this is still significant if your after maximum
performace, no? (Its actually the equivalent of 7.2 320x200 screens... :)

Leathal.

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