Re: feature request: detect CPU instruction set

[Bruno Haible]

Sam,

> >   AH_TOP([/* CPU and C ABI indicator */
> > #ifndef __i386__
> > #undef __i386__
> > #endif
> > ...
> > #ifndef __sparc64__
> > #undef __sparc64__
> > #endif
> > ])
> 
> what is this?

It's a set of preprocessor commands that get copied into config.h.in.
So that config.h will define the appropriate symbol (say, on 64-bit
SPARC systems, the __sparc64__ symbol), if the compiler does not already
define it.

> how is it supposed to be used?

#include <config.h>

#ifdef __sparc64__
  asm ("mulu64 ...");
#elif __sparc__
  asm ("mulu ...");

> does it somehow replace
> =================================================
> /* CPU */
> #ifndef __i386__
> #undef __i386__
> #endif
> ...
> #ifndef __x86_64__
> #undef __x86_64__
> #endif
> =================================================
> in, e.g., vacall.h.in?

If vacall.h.in includes config.h, then yes, you can remove that piece from
vacall.h.in.

Bruno