From: peter willy krause <wklux@yahoo.co.uk>
To: Martin <asmfreshmeat@gmx.de>
Cc: linux-assembly@vger.kernel.org, linux-assembly@mlists.in-berlin.de
Subject: Re: GAS/GCC Assembler Code Modification
Date: Sat, 15 May 2004 14:32:01 +0100 [thread overview]
Message-ID: <200405151432.01409.wklux@yahoo.co.uk> (raw)
In-Reply-To: <20040515112807.579e4d89@deepblack>
Am Samstag, 15. Mai 2004 10:28 schrieb Martin:
> Hi folks,
>
> I have a question regarding GAS and GCC.
> Does the GAS modify the Assembler Code? If I try to assemble (for
> example) the following line:
>
> popl %esi
>
> the gas changes that to
>
> pop %esi
though gas 'optimizes', which cannot be configured(!), in your example gas
doesn't, re listing by gas, itself! (my version ex binutils 2.14.90) -
apparently, your disassembler translates differently. compare the code...
the only 'optimization' by gas, which I'm aware of, is branches distance
coding and selection of alignment fill code. branches coding can be
forced to always 'long' (4 bytes) by declaring the destn label '.global'.
while assembling gas tries to deduce the oprands' formats by mnemonics and
register nameing and, tries some correction if the proper size specs were
missing, plus emanating a concerning warning (not an error!) message.
best,
hp
--
mail to 'hp': lx at lxhp : in-berlin : de
next prev parent reply other threads:[~2004-05-15 13:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-15 9:28 GAS/GCC Assembler Code Modification Martin
2004-05-15 10:15 ` sandeep
2004-05-15 13:32 ` peter willy krause [this message]
2004-05-15 20:08 ` Martin
2004-05-15 21:45 ` peter willy krause
2004-05-15 21:01 ` Martin
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