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Re: [PATCH] Introduce abi_word_mode
- From: Richard Sandiford <richard at codesourcery dot com>
- To: Andreas Krebbel <Andreas dot Krebbel at de dot ibm dot com>
- Cc: gcc-patches at gcc dot gnu dot org, David Edelsohn <dje at watson dot ibm dot com>
- Date: Mon, 02 Oct 2006 12:30:41 +0100
- Subject: Re: [PATCH] Introduce abi_word_mode
- References: <20060926111200.GA1983@de.ibm.com>
Andreas Krebbel <Andreas.Krebbel@de.ibm.com> writes:
> I'm currently working on a s390 patch which needs gcc to
> use internally a different word mode than the ABI-visible one.
> More precisely I want 32bit applications to
> make use of 64bit registers without breaking the 32bit ABI.
> I think the only target providing something like that is power
> The problem with this is that gcc is not aware that there
> might be two different word modes one representing the actual
> register width and one to be used whenever the ABI comes into
> play. Ulrichs idea was to introduce an abi_word_mode to address
> this. As the name suggests this would be the mode to be used
> whenever a register or a register-size value is externally
> visible. For everything else word_mode is used as before.
I didn't see any follow-up to this message (apologies if there
was and I missed it), so FWIW...
You don't document your new UNITS_PER_ABI_WORD macro, and the
term seems a bit woolly. What exactly do "word" and "abi word"
mean by your definition? I think we need something fairly
clear-cut so that non-s390 maintainers can tell whether they
should be using word_mode or abi_word_mode.