[avr-gcc-list] RE: [Bug target/31786] error: unable to find a register to spill in class 'BASE_POINTER_REGS'

[Eric Weddington]

> -----Original Message-----
> From: Joel Sherrill [mailto:address@hidden 
> Sent: Thursday, May 03, 2007 10:48 AM
> To: Eric Weddington
> Cc: 'Ralf Corsepius'; address@hidden
> Subject: Re: [Bug target/31786] error: unable to find a 
> register to spill in class 'BASE_POINTER_REGS'
> 
> Eric Weddington wrote:

> > I would strongly suggest that you and Joel take a look at 
> avr-libc again: it
> > has printf, many string functions, etc.
> >   
> Does it support file IO?

Avr-libc user manual online:
<http://www.nongnu.org/avr-libc/user-manual/>

Stdio specific docs:
<http://www.nongnu.org/avr-libc/user-manual/group__avr__stdio.html>

 
> At the bottom of the implementation of the stdio library what gets 
> called?  write() or
> an output character function? 

Output character function. This allows the end user to write to just about
anything, uarts, lcds, etc.
 
> I'm not saying it is impossible.  Only that RTEMS has a lot of POSIX 
> functionality and that
> we try to leverage newlib as much as possible for that support.  The 
> behavior of RTEMS is
> the same on every port and switching C libraries for a single target 
> decreases the cross
> platform value RTEMS offers.

Sure. Putting an OS (any of them) on a small 8-bit micro such as the AVR can
almost be overkill, depending upon the situation. You have to give it some
thought about what kinds of functionality do you really need on an AVR.

The upside is that avr-libc supports every single AVR device under the sun,
plus it contains AVR-specific functions (e.g. bootloader API).

I would also think that it depends on what your business case is; how many
customers do you have really wanting RTEMS on AVR?

Eric