Gas can't handle prefix generated by gcc

[H. J. Lu]

On Fri, Jul 23, 2004 at 01:43:33PM -0700, Zack Weinberg wrote:
> "H. J. Lu" <hjl@lucon.org> writes:
> 
> > On Fri, Jul 23, 2004 at 12:49:48PM -0700, Zack Weinberg wrote:
> >> Zack Weinberg <zack@codesourcery.com> writes:
> >> 
> >> > "H. J. Lu" <hjl@lucon.org> writes:
> >> >
> >> >> It seems that gcc uses a prefix syntax which gas doesn't handle. Does
> >> >> gcc always use " ; " as prefix separator?
> >> >
> >> > Yes.  It does that for cs/ds on branch hints, it does that for "rep"
> >> > on string instructions, it does that for "lock" on atomic updates.
> >> 
> >> Correction - it uses either " ; " or \n\t in all the above cases.
> >> 
> >
> > It looks like a gcc bug to me. Assembler has a way to define prefixes
> > for an instruction. Unfortunately, gcc uses something else. I will
> > close the assembler bug.
> 
> Not so fast.  Is the PREFIX_SEPARATOR mechanism (a) supported by GAS
> since time immemorial, and (b) supported by all other i386 assemblers
> since time immemorial?  If *either* of those is not true, GCC can't
> change.

It was added to gas on Jun 8, 1998. It is trivial to add a configure
test before using it. Gcc has many feature tests for assembler.


H.J.