RE: [avr-gcc-list] C code calling ASM functions

[Weddington, Eric]

> -----Original Message-----
> From: 
> address@hidden 
> [mailto:address@hidden
> org] On Behalf Of Gre7g Luterman
> Sent: Friday, January 25, 2008 9:48 AM
> To: address@hidden
> Subject: Re: [avr-gcc-list] C code calling ASM functions
> 
> --- David Brown <address@hidden> wrote:
> 
> > You really should do some basic search, and read the
> > avr gcc and 
> > avr-libc documentation before posting - you might
> > not find all your 
> > answers, but it will cover most things.
> > 
> >
> http://www.nongnu.org/avr-libc/user-manual/FAQ.html#faq_reg_usage
> >
> http://www.nongnu.org/avr-libc/user-manual/group__asmdemo.html
> >
> http://www.nongnu.org/avr-libc/user-manual/assembler.html
> >
> http://www.nongnu.org/avr-libc/user-manual/inline_asm.html
> 
> Hey!  That's a great list of resources.  However, I
> was reading through the first one and I think there's
> an error in the FAQ near the end.  It says:
> 
> "...8-bit return values are zero/sign-extended to 16
> bits by the caller..."
> 
> IIRC, it is actually the responsibility of the called
> function (the callee) to clear r25 when returning an
> unsigned byte.  The caller can presume this to be
> clear already.
> 
> Can someone correct this?
> 

Could you submit a bug report to the avr-libc project? Emails get
lost...

Thanks,
Eric W.