Sender: root AT delorie DOT com
Message-ID: <3784E681.5F6E7F23@inti.gov.ar>
Date: Thu, 08 Jul 1999 14:57:21 -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, Andris Pavenis <pavenis AT lanet DOT lv>
Subject: Re: .align directives in libc.a
References: <Pine DOT SUN DOT 3 DOT 91 DOT 990708094431 DOT 21287B-100000 AT is>
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Reply-To: djgpp-workers AT delorie DOT com

Eli Zaretskii wrote:

> On Wed, 7 Jul 1999, salvador wrote:
>
> > >  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.
>
> In what version?  2.7.2.1 emits ".align 2", which is 4 bytes with
> Binutils 2.8.1.

I'm talking about the binutils aligment between .o files, nothing related to
gcc.
That's the value that is limiting you (the comment was about the problem you'll
have trying to align to 16 bytes boundaries).

> > 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.
>
> So it seems the GCC maintainers go in that direction also.

At least for the experimental branch.

> Is this alignment specific for Linux, or will GCC do the same in the
> DJGPP configuration?

I had very important problems to compile this branch in DOS. I got an stage 3
compiler but I'm not so sure about how well configured is.
I'll test this compiler this weekend (long for me because this friday is our
independence day).

>  If it won't do so by default for DJGPP, is it
> hard to make it do so?  Andris, is this change, if it is needed, also
> hard, like what you described yesterday for the filler value?  If not,
> I think we should use the same alignment as Linux does.
>
> > I didn't time to run the benchmarks with it.
> > Is not very smart with the function starts (pushing all :-(
>
> If 2.95 is smarter, you could compile the benchmarks with -malign-*
> switches that force 16-byte alignment.  As far as alignment goes, this
> would give you the same effect.  Of course, you will need Binutils
> configured with 16-byte subsection alignment, to really see the
> effect.

I already got the patched 2.9.1.

SET

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