Sender: root AT delorie DOT com
Message-ID: <378365EE.208B74E7@inti.gov.ar>
Date: Wed, 07 Jul 1999 11:36:31 -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:
>
> > > So we need to change the value in Binutils, to get proper alignment.
> >
> > Yes but then we will bloat libc.
>
> I was thinking about doing the equivalent of ".balign 16,,7" between the
> objects, if that's possible.  That should bloat the library about 7K at
> the maximum (we have less than 1000 modules).

Ok, but currently binutils just align, I don't know how hard will be to achieve
it.

> Btw, won't ".balign 16,,7" near the entry into every function do the
> same, without changing Binutils?  (Of course, this leaves us with code
> produced by GCC.)

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.
The fact is that:

"The  aligment between modules is equal the maximun effective aligment you can
get in the .text section"

You can better, but just accidentally. So .balign 16,,7 needs binutils using 16
as aligment between modules.

SET

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