Subject: Re: The ELF ABI issue
To: None <>
From: Reinoud Zandijk <>
List: port-arm
Date: 03/27/2002 12:20:12
Hiya Richard,

On Wed, Mar 27, 2002 at 10:38:06AM +0000, Richard Earnshaw wrote:
> >  > The TLS register, on the other hand must be fixed (since the value is 
> >  > persistent across the whole thread).  If you pick r8 then you will 
> >  > fragment the register ranges, particularly when not inside a shared 
> >  > library.  There are different reasons why r9 or r10 might be the best 
> >  > choice, but r8 certainly would be a bad choice.
> > 
> > Ah, okay.  Chris Gilbert suggested r11 to me after I posted my message.
> *If* I had complete freedom to implement the ABI from scratch, then r11 
> would probably be my choice too.  However, there is too much legacy use of 
> r11 as a frame pointer to even consider that one now.

In legacy code ok... but still NetBSD could use it as a temp. storage of
the TLS ;) ... and why not use that r11 now in the ABI? ppl. are either 
conforming with it or now ... so i don't think its gonna bite anyway ...

> Note that the new ABI won't require a frame pointer, and I intend turning 
> it's use in the compiler off, just as soon as we can make other tools 
> (such as gdb) manage without it.

Hope so ... allthough a frame pointer is handy at times.... but if it gets 
loaded again and again anyway then its silly to waste a register on it