From: Johan Rydberg <jrydberg@rtmk.org>
To: Andreas Schwab <schwab@suse.de>
Cc: Robert Dewar <dewar@gnat.com>, jh@suse.cz, gcc@gcc.gnu.org
Subject: Re: i386 and asm jumping
Date: Tue, 07 May 2002 10:31:00 -0000 [thread overview]
Message-ID: <20020507193239.G25172@cockmaster.bredbandsbolaget.se> (raw)
In-Reply-To: <jehelkaxep.fsf@sykes.suse.de>; from schwab@suse.de on Tue, May 07, 2002 at 15:40:46 +0200
On 2002.05.07 15:40 Andreas Schwab wrote:
: dewar@gnat.com (Robert Dewar) writes:
:
: |> > It is not possible. ASM statements may not jump.
: |> > You may want to use computed goto GCC extension istead.
: |>
: |> Seems a pity, this is quite a serious restriction in capability
: |> compared with Asm inserts in other compilers.
:
: What's wrong with computed goto in this situation?
What I would like to do is to replace the following code
with inline assembler:
if (--cnt == 0)
goto HANDLER;
goto NEXT;
The code above will generate; load cnt into register,
decrement register, store register and jump to HANDLER
if zero flag is set. I would like to replace this with
the following assembler code:
decl cnt
jz HANDLER
jmp NEXT
Speed is everything :)
regards
johan
next prev parent reply other threads:[~2002-05-07 17:29 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-07 5:49 Robert Dewar
2002-05-07 6:48 ` Andreas Schwab
2002-05-07 10:31 ` Johan Rydberg [this message]
2002-05-07 15:23 ` Richard Henderson
2002-05-08 4:15 ` Bernd Jendrissek
2002-05-07 7:45 ` Michael Matz
-- strict thread matches above, loose matches on Subject: below --
2002-05-07 16:33 Erik Schnetter
2002-05-08 2:43 ` Andreas Schwab
2002-05-09 9:01 ` Erik Schnetter
2002-05-07 7:30 Robert Dewar
2002-05-07 9:03 ` Peter Barada
2002-05-07 5:06 Johan Rydberg
2002-05-07 5:15 ` Jan Hubicka
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