From: mlsoftware AT aol DOT com (Mlsoftware)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: 32 bit Memory Operations
Date: 4 Jun 1997 06:02:10 GMT
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References: <865393956 DOT 26276 AT dejanews DOT com>
To: djgpp AT delorie DOT com
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The following macros are about as fast as you're going to get. They accept
words rather than bytes, as they copy 4 bytes at a time.
1 WORD =  4 BYTES, so when you tell it how many words to copy, make sure
it's the (# OF BYTES/4)

The following are stolen from Brennan's AT&T Assembly FAQ, I think.

#define quad_memcpy(src, dest, numwords) \
__asm__ __volatile__ ( \
  "cld\n\t" \
  "rep\n\t" \
  "movsl" \
  : : "S" (src), "D" (dest), "c" (numwords) \
  : "%ecx", "%esi", "%edi" )

#define quad_memset(value, dest, numwords) \
__asm__ __volatile__ ( \
  "cld\n\t" \
  "rep\n\t" \
  "stosl" \
  : : "a" (value), "D" (dest), "c" (numwords) \
  : "%ecx", "%edi" )