Subject: Re: The ELF ABI issue
To: None <Richard.Earnshaw@arm.com>
From: Reinoud Zandijk <firstname.lastname@example.org>
Date: 03/27/2002 12:20:12
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