Re: [avr-libc-dev] [bug #12739] Gcc assumes that target libc provides ffs function

[Björn Haase]

Am Dienstag, 19. April 2005 21:41 schrieb E. Weddington:
> Joerg Wunsch wrote:
> >As Eric Weddington wrote:
> >>For reference, the ffs function can be found in newlib.
> >><http://sources.redhat.com/newlib/libc.html#SEC187>
> >
> >Which probably took it straight from the BSD lib. ;-)
> >
> >As the function is so simple, and the BSD copyright matches our
> >copyright (clause 3 may officially be omitted), we can easily import
> >it.
>
> As a side note, I find it odd that the GCC test suite would require such
> a non-ANSI standard function to be in the libc. But yeah, it's easy
> enough to add.
>
> Eric
I think the background is that for some targets there is a special instruction 
for this purpose. Gcc has special support for a RTL instruction pattern that 
is then matched to a built-in function. The test cases seem to be useful for 
testing this feature.

Yours,

Björn