Re: Fix fr30 libgloss build

[Jeff Johnston <jjohnstn@redhat.com>]

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Looks fine.  Feel free to push.

-- Jeff J.

On Thu, Dec 14, 2023 at 9:47 AM Jeff Law <jeffreyalaw@gmail.com> wrote:

>
> gcc-14 will default to c99 and as a result a fair amount of old code in
> newlib (particularly libgloss) is failing to build.  I don't offhand
> know how many patches will be necessary to fix the various failures.
> I'll just pick them off one by one from my tree.
>
> This particular patch works around the return-mismatch problem
> syscalls.c for fr30.
>
> That file is a bit odd in that most functions are declared as returning
> an integer, but the implementations look like:
>
> > int
> > _read (file, ptr, len)
> >      int    file;
> >      char * ptr;
> >      int    len;
> > {
> >   asm ("ldi:8 %0, r0" :: "i" (SYS_read) : "r0");
> >   asm ("int   #10");
> >
> >   return;
> > }
>
>
> Note the lack of a value on the "return" statement.  The assumption is
> that the interrupt handler implementing syscalls will put the return
> value into the proper register, so falling off the end of the C function
> or returning with no value works in the expected way.  It's not good
> code, but it probably works.
>
> Working from that assumption I decided to just use a pragma to disable
> the upgraded diagnostic from GCC -- essentially preserving existing
> behavior.
>
> This is the only fr30 specific issue that needs to be resolved and the
> only issue (so far) I've seen of this specific nature.
>
> OK for the trunk?
>
> jeff
>