Hi Simon -- and sorry for the dupe.
On Wed, 17 Apr 2013 11:28:07 -0700, Simon Glass sjg@chromium.org wrote:
I tried using:
#ifdef USE_HOSTCC crc = htobe32(crc); #else crc = cpu_to_be32(crc); #endif memcpy(output, &crc, sizeof(crc));
This is one instruction (4 bytes, 16%) smaller, but I suspect quite a lot slower due to the overhead of a very small memcpy().
43e2c1d8: e28d1008 add r1, sp, #8 43e2c1dc: e3a02004 mov r2, #4 43e2c1e0: e6bf0f30 rev r0, r0 43e2c1e4: e5210004 str r0, [r1, #-4]! 43e2c1e8: e1a00004 mov r0, r4 43e2c1ec: eb001af7 bl 43e32dd0 <memcpy>
How about replacing the memcpy with an explicit put_unaligned(), similar to what was done in
http://www.mail-archive.com/u-boot@lists.denx.de/msg109555.html
with get_unaligned()? The code will be longer than above, but shorter than the above plus the memcpy(), and faster too -- actually, I'm surprised that the compiler does not unroll the memcpy() on its own, considering the size argument is a constant.
Regards, Simon
Amicalement,