Re: [ros-dev] Re: [ros-svn] [royce] 14523: patch by kjk::hyperion, fix syntax of gcc inline asm

[Hartmut Birr]

Filip Navara wrote:

>   royce(a)svn.reactos.com wrote:
>
> >   patch by kjk::hyperion, fix syntax of gcc inline
> > asm
> >
> >
> >  Updated files:
> >  trunk/reactos/hal/halx86/include/hal.h
> >   
> >  
>  This is not acceptable solution IMHO...there are problems with certain
>  GCC versions assigning AMD64 registers on i386. See revision 13587 and
>  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10153.
>
>  - Filip 
Hi,

I think that the "0" in the output operand is the problem (same register
like input).

__asm__ __volatile__("movb %%fs:(%1),%0":"=q" (b):"0"
(offset));

Gas is sometimes a little bit buggy and puts the same value frome the
first operand the second. This results in message like this:

{standard input}: Assembler messages:
{standard input}:2474: Error: `%fs:(%bl)' is not a valid base/index
expression

The correct workeround is something like this:

__asm__ __volatile__("movb %%fs:(%1),%0":"=q" (b):"r"
(offset));

or

__asm__ __volatile__("movb %%fs:(%1),%0":"=r" (b):"r"
(offset));

- Hartmut