Re: [patch 2.6.17-rc5 1/2] i386 memcpy: use as few moves as possiblefor I/O

[H. Peter Anvin]

One concern: this is not the standard return value for memcpy().  It either needs a 
comment to that effect (stating it returns a pointer to the end of the area), or just make 
it return void.

Also, the formatting looks nonstandard.

>  
>  /*
> + * Do memcpy with as few moves as possible (for transfers to/from IO space.)
> + */
> +static inline void * __minimal_memcpy(void * to, const void * from, size_t n)
> +{
> +int d0, d1, d2;
> +__asm__ __volatile__(
> +	"rep ; movsl\n\t"
> +	"testb $2,%b4\n\t"
> +	"jz 1f\n\t"
> +	"movsw\n"
> +	"1:\n\t"
> +	"testb $1,%b4\n\t"
> +	"jz 2f\n\t"
> +	"movsb\n"
> +	"2:"
> +	: "=&c" (d0), "=&D" (d1), "=&S" (d2)
> +	:"0" (n/4), "q" (n), "1" ((long) to), "2" ((long) from)
> +	: "memory");
> +return to;
> +}


	-hpa
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