[PATCH] x86: Add .nop directive to assembler

[Maciej W. Rozycki]

On Fri, 16 Feb 2018, H.J. Lu wrote:

> All fixed.  Here is the updated patch.  OK for master?

 I skimmed over briefly only.  I think the convention for the manual is to 
use the generic term `no-op instruction' rather than `@code{NOP}'.  

 Firstly, not all targets we support have an actual NOP mnemonic.  And 
even with x86 the encodings you choose are not true architectural NOP 
instructions, but just machine code encodings which happen to execute 
quickly and with no visible effects (and e.g. for MIPS `addiu $0, $3, -1' 
yields no observable effect, however nobody calls that `nop'; there are 
millions of such MIPS machine code encodings).

  Maciej