The alignment logic for reverse moves is reversed, because the initial
edi, and therefore edx, points to the last byte, not to one byte
beyond the end.  Therefore, in the fully aligned case it will end in
11 binary, not in 00 binary as for the forward case.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Aligning versions of memcpy/memmove/mempcpy/memset for libcom32.

Replace the C version of memmove() with a slightly more optimized
assembly version that at least can do dword-sized rep moves.