Sender: root AT delorie DOT com
Message-ID: <37836D80.940DCA74@inti.gov.ar>
Date: Wed, 07 Jul 1999 12:08:48 -0300
From: salvador <salvador AT inti DOT gov DOT ar>
Organization: INTI
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To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
CC: djgpp-workers AT delorie DOT com
Subject: Re: .align directives in libc.a
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Reply-To: djgpp-workers AT delorie DOT com

Eli Zaretskii wrote:

> On Wed, 7 Jul 1999, salvador wrote:
>
> > Nope, binutils assumes the current module starts at address 0 and doesn't know
> > anything about the previous. This "address 0" is in fact aligned to an 8 bytes
> > boundary. So now suppose you say .balign 16 before the first function and the
> > real adress is 00008, now as the binutils thinks this address is 0 will not put
> > any padding instructions and you'll end with an 8 bytes aligment and not 16 as
> > you asked.
>
> So this means that all the .align directives in the current libc sources
> are useless, right?

No if they are 8 or less ;-). But yes if you use 16.

>  And the same goes for the .align directives emitted
> by GCC, for function entry points and labels?

They are normally 8 bytes or less for djgpp.
Let me see what about gcc 2.96 new experimental optimization branch ....
Wow! it uses .align 16 by default for Linux (-O9 just in case ;-), let me see a loop
...
.p2align 4! for entry points of loops.
I know for sure gcc 2.95 for DOS doesn't do it, this compiler I'm testing is very
experimental and according to people in the egcs list should beat MSVC 6.0. I didn't
time to run the benchmarks with it.
Is not very smart with the function starts (pushing all :-(

SET

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