Mail Archives: djgpp/1999/07/16/05:28:52
From: | robk AT cyberway DOT com DOT sg (Rob Kramer)
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Newsgroups: | comp.os.msdos.djgpp
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Subject: | 386 SX versus DX - 'int' datatransfer
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Date: | Fri, 16 Jul 1999 16:39:31 +0800
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Message-ID: | <MPG.11f97084d7231b29989686@news.cyberway.com.sg>
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Organization: | Infologic Pte Ltd
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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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Reply-To: | djgpp AT delorie DOT com
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Hi all,
One of my applications (involving a GIF-decoder) I recently tried on a
386 SX machine. The decoder is terribly slow in that case. The original
pre-DJGPP obsolete 16-bit version of the application is way faster. (I'm
not sure whether the 32-bit version is faster than the 16-bit version on
a 386 DX)
The 16-bit version uses shorts as working variables in the decoder, the
32-bit version uses ints. Could the big difference between running on a
SX and a DX be caused by the fact that 32-bit transfers are not a nice
thing on a SX databus?
Then would it help if I change back to shorts, or will this harm the
performance of the decoder on 32 bits databus machines. Note that the
decoder doesn't actually need ints, but I thought ints were friendlier to
a Pentium architecture. That's what it normally runs on, but I have to
support 386SX too :(
Cheers!
Rob Kramer
Singapore
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