From: "Maciej W. Rozycki" <macro@linux-mips.org>
To: Richard Sandiford <rdsandiford@googlemail.com>
Cc: binutils@sourceware.org
Subject: Re: [PATCH 1/2] MIPS/GAS: Fix o32 LD to the base register
Date: Mon, 18 Oct 2010 17:05:00 -0000 [thread overview]
Message-ID: <alpine.LFD.2.00.1010181752570.15889@eddie.linux-mips.org> (raw)
In-Reply-To: <g48w1w2b8a.fsf@richards-desktop.stglab.manchester.uk.ibm.com>
On Mon, 18 Oct 2010, Richard Sandiford wrote:
> > 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?
Because I've got a hole in my imagination here? :/
> Seems a shame to use $at when we don't need to.
Indeed, although we're no better elsewhere, consider e.g.:
$ cat ld-base-1.s
.comm foo, 1024
ld $4, foo
$ as -32 -o ld-base-1.o ld-base-1.s
$ objdump -dr ld-base-1.o
ld-base-1.o: file format elf32-tradbigmips
Disassembly of section .text:
00000000 <.text>:
0: 3c010000 lui at,0x0
0: R_MIPS_HI16 foo
4: 8c240000 lw a0,0(at)
4: R_MIPS_LO16 foo
8: 8c250004 lw a1,4(at)
8: R_MIPS_LO16 foo
c: 00000000 nop
where $a1 could be used in place of $at, couldn't it?
I'll cook up something, though I only have worms to offer it would seem.
Maciej
next prev parent reply other threads:[~2010-10-18 17:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-17 16:22 Maciej W. Rozycki
2010-10-18 7:48 ` Richard Sandiford
2010-10-18 17:05 ` Maciej W. Rozycki [this message]
2010-10-31 22:46 ` [PATCH 1/5] " Maciej W. Rozycki
2010-11-01 21:28 ` Richard Sandiford
2010-11-01 21:34 ` Richard Sandiford
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