From: Daniel Jacobowitz <drow@mvista.com>
To: Paul Koning <pkoning@equallogic.com>
Cc: aoliva@redhat.com, binutils@sources.redhat.com, echristo@redhat.com
Subject: Re: MIPS assembler branch relaxations
Date: Sat, 14 Sep 2002 16:35:00 -0000 [thread overview]
Message-ID: <20020914212828.GA22770@nevyn.them.org> (raw)
In-Reply-To: <15747.43100.460148.599969@pkoning.akdesign.com>
On Sat, Sep 14, 2002 at 05:21:32PM -0400, Paul Koning wrote:
> >>>>> "Daniel" == Daniel Jacobowitz <drow@mvista.com> writes:
>
> Daniel> On Sat, Sep 14, 2002 at 02:59:45AM -0300, Alexandre Oliva
> Daniel> wrote:
> >> This patch arranges for the MIPS assembler to turn out-of-range
> >> branches into jumps. No regressions are introduced in the
> >> binutils testsuites for a mips-linux build. Details on how it is
> >> done are in comments in the beginning of the patch. Ok to
> >> install?
>
> Daniel> A couple of thoughts:
>
> Daniel> + beql reg1, reg2, 1f + nop + beqzl $0, 2f + nop + 1: j[al]
> Daniel> label + delay slot (executed only if branch taken) + 2:
>
> Daniel> Why beqzl? Admittedly, I don't know much about MIPS
> Daniel> hardware, but I'd think that just "b" would probably be
> Daniel> faster, since that's the normal unconditional branch.
>
> Not only that, but MIPS64 explicitly deprecates all flavors of "branch
> likely" which is why gcc has a way to avoid generating them. So the
> assembler should either have the same conditional stuff, or avoid them
> entirely.
That's not a problem here - Alex's patch only generated branch-likely
in response to existing branch-likely in the source.
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
next prev parent reply other threads:[~2002-09-14 21:28 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-14 4:49 Alexandre Oliva
2002-09-14 14:28 ` Daniel Jacobowitz
2002-09-14 14:46 ` Eric Christopher
2002-09-14 21:33 ` Daniel Jacobowitz
2002-09-14 21:33 ` Eric Christopher
2002-09-14 15:00 ` Paul Koning
2002-09-14 16:35 ` Daniel Jacobowitz [this message]
2002-09-14 18:43 ` Paul Koning
2002-09-14 21:39 ` Thiemo Seufer
2002-09-14 22:18 ` Alexandre Oliva
2002-09-15 2:25 ` Thiemo Seufer
2002-09-15 3:38 ` Alexandre Oliva
2002-09-15 0:49 ` Alexandre Oliva
2002-09-15 9:15 ` Daniel Jacobowitz
2002-09-16 11:56 ` Richard Henderson
2002-09-17 0:09 ` Alexandre Oliva
2002-09-17 0:26 ` Richard Henderson
2002-09-17 0:38 ` Thiemo Seufer
2002-10-09 16:51 ` Alexandre Oliva
2002-10-09 16:54 ` Alexandre Oliva
2002-10-09 17:17 ` H. J. Lu
2002-10-11 13:08 ` Eric Christopher
2002-09-14 14:39 ` H. J. Lu
2002-09-14 23:12 ` Alexandre Oliva
2002-09-15 9:13 ` H. J. Lu
2002-09-15 15:32 ` Eric Christopher
2002-09-15 16:53 ` H. J. Lu
2002-09-15 1:00 ` Alexandre Oliva
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