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Re: accept 64-bit constant addresses in mips n32
- From: Thiemo Seufer <ica2_ts at csv dot ica dot uni-stuttgart dot de>
- To: binutils at sources dot redhat dot com
- Date: Tue, 8 Apr 2003 05:06:16 +0200
- Subject: Re: accept 64-bit constant addresses in mips n32
- References: <orbrzknwnm.fsf@free.redhat.lsd.ic.unicamp.br>
Alexandre Oliva wrote:
> Even though n32 has a 32-bit address space, sometimes it is important
> to be able to reference uncached memory regions or so in n32,
(C)KSEG can be accessed, and 64-bit addressing is out of spec.
> and
> having the assembler drop the upper 32 bits of such addresses surely
> doesn't help. This patch fixes the problem. Approved by Eric
> Christopher. I'm checking it in.
After thinking a bit about this, I'm still not sure if the 'fix' is ok.
n32 normally guarantees properly sign-extended 32-bit addresses, and
people may rely on it for pointer arithmethics (in broken code).
IMHO the assembler should complain about attempted 64-bit addressing
in order to catch compiler bugs.
For what actual usage scenario was this patch developed?
Thiemo