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Re: new triplet for x32 psABI?

From: Michael LIAO
Subject: Re: new triplet for x32 psABI?
Date: Mon, 3 Oct 2011 16:47:57 -0700

On Mon, Oct 3, 2011 at 4:03 PM, Mike Frysinger <address@hidden> wrote:
> On Monday, October 03, 2011 18:57:28 Michael LIAO wrote:
> please don't top post

sorry, it's my first post on mailing.

>> Most examples would be related to tools generating code.
>> Suppose you have a software package with several hard-coded fully
>> optimized assembly file for different targets. Your build system need
>> to know the current target as well as target ABI to select the correct
>> assembly file to build it. It even desirable if it includes a simple
>> script to help generate assembly code (like the one in OpenSSL), you'd
>> better know the target ABI to prepare proper glue code without
>> breaking ABI.
> hjlu posted examples to the x32 site as to handle this.  the only difference
> between x86_64 and x32 is the size of the pointers.

Besides the pointer size, there are other differences like indirect
branch which need different code sequence on x32 and x64. Indirect
branch would be used in assembly code (yeah, concrete example would
valuable here but indirect branch should be used potentially and
possibly in assembly code.) If the assembly code use indirect branch,
it needs to know the target ABI and generate/use difference code path.

> please explain why his example won't cover the OpenSSL's needs.  (side note;
> OpenSSL is a terrible example to use because (1) they don't even use autoconf
> or any autotools and (2) they don't generally use sane tuples like the config
> project).
> -mike

Openssl may not a good example and I just used as I remembered it uses
assembly code.

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