On Sat, Nov 10, 2012 at 2:05 AM, rusi <rustompmody at gmail.com> wrote: > In x86 assembler > mov ax, 0 > is 4 bytes Three bytes actually, B8 00 00 if my memory hasn't failed me. BA for DX, B9 ought to be BX and BB CX, I think. But yes, the xor or sub is two bytes and one clock. ChrisA