Re: [Nasm-devel] [PATCH] Add np and similar prefixes to instructions that should have them

[H. P. A. <hp...@zy...>]

On 02/19/2013 09:39 PM, Ben Rudiak-Gould wrote:
> This adds "np" to a bunch of SSE-style instructions that should have
> it, "norep" (which was implemented but unused) on quasi-SSE
> instructions that use F2 and F3 as instruction extensions but 66 for
> operand size, "nof3" (newly implemented) on a few instructions,
> "norexw" on some instructions that have only 32-bit and 64-bit
> versions, and one NOLONG. It also removes some incorrect "np"s,
> changes some "f3"s to "f3i"s, and fixes the decoding of the
> XCHG/NOP/PAUSE mess: F390 is always PAUSE even when rex.b=1 (at least
> according to XED).

It should have been REX.R not REX.B, to prevent:

	[rep] xchg r8,rax

... from being treated as NOP or PAUSE.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.