Re: [U-Boot] [PATCH 1/3] memcpy: use 32-bit copies if possible

Dear Alessandro Rubini,

In message 20091008074114.GA30203@mail.gnudd.com you wrote:

Since int is 32 also on 64bit systems, I used unsigned long.

Note that this is not guaranteed, though. It could be 64 bit as well.

	/* do it one word at a time (32 bits or 64 bits) if possible */
	if ( ((count | (int)s) & (sizeof(long) - 1)) == 0) {
		count /= sizeof(long);
		cl = (c & 0xff) | ((c & 0xff) << 8);
		cl |= cl << 16;
		if (sizeof(long) > 4)
			cl |= cl << 32;

How about:

cl = 0; for (i=0; i<sizeof(long); ++i) { cl <<= 8; cl |= c & 0xff; }

GCC optimization will do the rest...

Best regards,

Wolfgang Denk