Re: [Tinycc-devel] Merging patches...

[Rob Landley]

On Monday 09 October 2006 2:00 pm, Daniel Glöckner wrote:
> On Sun, Oct 08, 2006 at 11:49:53PM -0400, Rob Landley wrote:
> > Would someone please explain to me why stdarg.h says the va_args macros 
> > are "only correct for i386", but we have an arm eabi patch pending that 
> > doesn't touch this file?  Which is wrong?
> 
> The both are wrong.
> The macros are correct for non-EABI ARM as well.
> EABI ARM needs something like:
> 
> #define va_arg(ap,type) ( \
>         *(type *)((ap = (va_list)((ap + (((sizeof(type) + 3) & ~3) \
>                                          + (__alignof__(type) > 4) \
>                                            * (__alignof__(type) - 1)) \
>                                         - (va_list)0) \
>                                   & - (1 + (__alignof__(type) > 4) \
>                                            * (__alignof__(type) - 1)))) \
>                   - ((sizeof(type) + 3) & ~3)))
> 
> This "thing" generates the shortest instruction sequence.
> Feel free to reformat it :-)

Is that the only one that needs per-arch tweaking?

I need to figure out how to handle config-specific headers.  (Is there some "I 
am currently building for this architecture" #ifdef I can check?  And it's 
too bad unifdef isn't part of the standard build environment, but I can 
probably do something evil with sed...)

Alas, I don't yet have a good enough mental model of the tcc build process to 
know where to whack it with the big hammers yet...

Rob
-- 
Never bet against the cheap plastic solution.