From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Jackson <mpfj-list@mimc.co.uk>
Date: Fri, 09 Oct 2009 11:11:16 +0100
Subject: [U-Boot] [PATCH V2 1/3] memcpy: copy one word at a
	time	if	possible
In-Reply-To: <4ACEBF19.4010902@free.fr>
References: <cover.1255000877.git.rubini@unipv.it>	<45d5e3a574bf4844f46f50b2c88054a5b28f973b.1255000877.git.rubini@	unipv.it>	<20091008204431.07341E8B31D@gemini.denx.de>
	<4ACEBF19.4010902@free.fr>
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To: u-boot@lists.denx.de

Chris Moore wrote:
> I agree wholeheartedly with the idea but shouldn't it be more like this 
> (untested) code :
> 
> void * memcpy(void *dest, const void *src, size_t count)
> 
> {
> 	char *d8, *s8;
> 	unsigned long *dl = dest, *sl = src;
> 

In here, would it be overkill to add byte copying until data is aligned, and
then fall into the aligned copy code.

In that case, you'd still gain a speed increase if you're starting at an unaligned
address ?

> 	/* while all data is aligned (common case), copy multiple bytes at a time */
> 	if ( (((int)(long)dest | (int)(long)src) & (sizeof(*dl) - 1)) == 0) {
> 		while (count >= sizeof(*dl)) {
> 			*dl++ = *sl++;
> 			count -= sizeof(*dl);
> 		}
> 	}
> 
> 	d8 = (char *)dl;
> 	s8 = (char *)sl;
> 
> 	/* copy any remaining data byte by byte */
> 	while (count--)
> 		*d8++ = *s8++;
> 
> 	return dest;
> }

Regards
Mark