[PATCH] x86: allow suffix-less sign-extending movsb, movsw, and movsl

[Jan Beulich]

>>> On 01.07.16 at 15:43, <jonas-devlists@watlock.be> wrote:

> Jan Beulich wrote on Fri, 01 Jul 2016:
> 
>> Nor do we support (prior to this patch) the respective movsb and
>> movsw. Adding support for them (and then consistently, i.e.
>> including movsl) is the purpose of this patch.
> 
> I think that is a really bad idea. movsb, movsw and movsl are existing  
> mnemonics for completely different opcodes (as in "rep movsb"). It  
> also seems to be against the spirit of AT&T syntax, which normally  
> requires you to explicitly specify all operand sizes fully with the  
> mnemonic in all cases, even if the assembler could in theory deduce  
> them from the operands.

Where's that written down please? As said in the movz patch
description yesterday, movz{b,w} and movs{b,w,l} really are
the odd ones - everything else gets accepted without suffixes when
they're deducible from operands. And I'm of the strong opinion
that such inconsistencies should be eliminated. (And btw., no-one's
going to be forced to omit the suffixes, if they like them.)

Jan