Enable 32-bit Alignment

[Menezes, Evandro]

HJ, 

> Can you add nops-4.d and x86-64-nops-4.d?

Sure.

> I'd like to see some further changes:
> 
> 1. For N byte alignment padding up to 15 bytes:
>    a. On 32bit,
>       i. Use (N - 1) 66 prefixes + 90 by default.
>       ii. When Pentium Pro or newer is specified, use (N - X) 66
>           prefixes + new nop insn with X bytes.
>       iii. For Pentum or older, use the old padding.

If #2 is for Ppro or newer and #3, for P5 or older, when does #1 come into play?  #1 does seem to be detrimental on 486 and older.

Anyways, I wasn't able to find good information on older processors (before Ppro), so I'd rather leave them as is.  

>    b. On 64bit, use (N - X) 66 prefixes + new nop insn with X bytes.

I.e., no change, right?

> 2.  For alignment padding between 16 and 30 bytes, use 2 x (< 
> 15byte nops).
> 3.  For 31 byte alignment padding, use 2 x (15byte nops) + 1byte nop.

I disagree.  The idea is to keep the number of NOPs down and by doing so there would be some cases that would result in one more NOP than in the way I proposed in my patch.  Other than neatness, is there any reason you're proposing this?

Thanks,

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Evandro Menezes               AMD            Austin, TX