From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: mem copies
Date:	Mon, 14 Jul 1997 22:06:06 +0000
Organization:	Two pounds of chaos and a pinch of salt
Lines:	27
Message-ID:	<33CAA2CE.6099@cs.com>
References:	<33C98EA7 DOT 1A09 AT wanadoo DOT fr>
Reply-To:	fighteer AT cs DOT com
NNTP-Posting-Host:	ppp202.cs.com
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Alan Poppleton wrote:
> 
> I have allocated two memory blocks with the malloc function.  What is
> the fastest method of copying from one to the other?  Would assembler
> help? If so what is the code?  I am currently using memcpy to copy but I
> need to be as fast as possible.  Also is there are faster method of
> setting a chunk of memory to a certain value than the memset function.

With optimizations on ('-O' switch or its variants '-O1', '-O2', '-O3',
etc.), memset() and memcpy() should compile to very efficient code.  If
you doubt this, try using the '-S' switch to generate assembly code, and
read it to see what the compiler produced.  The '-m486' option might
produce faster code on 486 computers as well.

If you're using a Pentium, then you may want to do some assembly coding
to get optimal speed, or try downloading PGCC, a version of gcc that
incorporates Pentium optimizations.  Visit
<http://www.delorie.com/djgpp/> to get the URL - it's right at the top
of the page.

-- 
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|      John M. Aldrich       | "Always listen to experts.  They'll  |
|       aka Fighteer I       | tell you what can't be done, and why.|
|   mailto:fighteer AT cs DOT com   | Then do it."                         |
| http://www.cs.com/fighteer |                - Lazarus Long        |
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