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From: Richard Sandiford <rdsandiford@googlemail.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Mail-Followup-To: "Maciej W. Rozycki" <macro@linux-mips.org>,binutils@sourceware.org, rdsandiford@googlemail.com
Cc: binutils@sourceware.org
Subject: Re: [PATCH 1/2] MIPS/GAS: Fix o32 LD to the base register
References: <alpine.LFD.2.00.1010130023180.15889@eddie.linux-mips.org>
Date: Mon, 18 Oct 2010 07:48:00 -0000
In-Reply-To: <alpine.LFD.2.00.1010130023180.15889@eddie.linux-mips.org>	(Maciej W. Rozycki's message of "Sun\, 17 Oct 2010 17\:22\:31 +0100	\(BST\)")
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"Maciej W. Rozycki" <macro@linux-mips.org> writes:
>  Here's another one:
>
> $ cat ld-base.s
> 	ld	$4, ($4)
> $ mips-linux-as -o ld-base.o ld-base.s
> $ mips-linux-objdump -d ld-base.o
>
> ld-base.o:     file format elf32-tradbigmips
>
>
> Disassembly of section .text:
>
> 00000000 <.text>:
>    0:	8c840000 	lw	a0,0(a0)
>    4:	00000000 	nop
>    8:	8c850004 	lw	a1,4(a0)
>
> Ouch!
>
>  Fixed thus and regression tested for mips-linux, mips64-linux, 
> mipstx39-elf, mipsisa64-elf and mips-ecoff targets and their little-endian 
> counterparts.  The new code produced looks like this:
>
> $ mips-linux-objdump -d ld-base.o
>
> ld-base.o:     file format elf32-tradbigmips
>
>
> Disassembly of section .text:
>
> 00000000 <.text>:
>    0:	00800821 	move	at,a0
>    4:	8c240000 	lw	a0,0(at)
>    8:	8c250004 	lw	a1,4(at)

Why are you doing it this way, rather than reversing the loads?
Seems a shame to use $at when we don't need to.

Richard