* Andi Kleen ([EMAIL PROTECTED]) wrote: > Jeremy Fitzhardinge <[EMAIL PROTECTED]> writes: > > > > It's a pity that gas seems to generate plain 0x90 nops rather than > > long-nop forms here. I thought it could do that. > > .p2align does it. >
Sadly, p2align does not apply well to my context. I have to align on 4 bytes boundaries - 1 for the 4 bytes mov, so, if I would use p2align, I would end up aligning on 4 bytes with p2align and then add 3 bytes (worse case: adding 3 + 3 = 6 bytes of nops). However, with the .org arithmetic, I can simply add then quantity of nops needed to make my alignment on 4 bytes - 1, so the worse case becomes adding 3 bytes. The example is: originally: address & 3 = 1 * p2align p2align adds 3 bytes to align on 4 bytes boundaries we add 3 bytes to align on the next 4 bytes - 1, so the immediate value within the instruction is aligned on 4 bytes boundaries * org we add 2 bytes to be aligned on the next 4 bytes - 1. And yes, it's a pity there is no way to produce the long-nops there. :( Mathieu > -Andi -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/