Re: Where is it written?

[Andrea Arcangeli <andrea@suse.de>]

On Sat, Nov 11, 2000 at 05:17:49PM -0600, Peter Samuelson wrote:
> I'd say go for it -- set up a mailing list and flesh out a better x86
> ABI. [..]

I think it doesn't worth to break binary compatilibity at this late stage.

> design such.)  One issue: ideally you want to use 64-bit regs on AMD
> Hammer for long longs, but then you leave out all legacy x68s. :(

We can't in compatibilty mode because the rex regs are available _only_ in
64bit mode and even assuming the hardware would support that I would not
recommend that since as you said that binary would not run anymore on any other
x86 so causing pain.  Recompiling a program with native x86-64 gcc 64bit (that
uses the 64bit ABI) is the right way to go in that case (64bit mode uses 1
64bit register for long long as all other 64bit architectures of course).

> AIUI gcc can cope OK with multiple ABIs to be chosen at runtime, am I
> right?  IRIX, HP-UX and AIX all have both 32-bit and 64-bit ABIs.

Yes as in other systems, 32bit mode and 64bit mode needs different ABI and they
will coexist in the same system.

Andrea
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/