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Re: r4600 flag

Subject: Re: r4600 flag
From: Thiemo Seufer <>
Date: Tue, 31 Jul 2001 09:28:22 +0200
In-reply-to: <>
User-agent: Mutt/1.3.18i
Pete Popov wrote:
> in arch/mips/Makefile, we use the -mcpu=r4600 flag for MIPS32. What's 
> interesting is that the use of this flag can cause the toolchain to 
> generate incorrect code.

Which toolchain versions, what patches applied to it?

> For example:
> la k0, 1f
> nop
> 1: nop
> The la macro is split into a lui and a daddiu. The daddiu is not correct 
> for a mips32 cpu. Getting rid of the -mcpu=4600 fixes the problem and 
> the daddiu is then changed addiu.

This is IIRC a known bug in at least current binutils CVS, a patch
to fix it really was already discussed.

> Is there a truly correct -mcpu option for a mips32 cpu?

In theory, no -mcpu option (which is to be deprecated in
favor of -march/-mtune) and -mips32 as ISA flag _should_ work.

In practice, the patch which adds this to gas was discussed on the
binutils list the last days and is likely to go in CVS
today or tomorrow.


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