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Re: GCC and memory segments

From: Jim Wilson <wilson at specifixinc dot com>
To: Bernd Jendrissek <berndfoobar at users dot sourceforge dot net>
Cc: gcc at gcc dot gnu dot org
Date: Thu, 25 Sep 2003 23:30:41 -0700
Subject: Re: GCC and memory segments
References: <001701c381b1$13819600$7303230a@PTR> <20030925084217.GB30219@prism.co.za>

Bernd Jendrissek wrote:

I believe DJ Delorie has done some work on realmode x86 code generation.


This is off the link I gave.  To be a little more precise
	http://www.delorie.com/djgpp/16bit

So how do I work with segments?

I would suggest making Pmode be PSImode. This will let you distinguish pointers from integers. You can then write PSImode patterns that know how to load the upper part of an address into a segment register. This effectively makes every pointer a far pointer. After you get this working, you can worry about optimizing it to avoid redundant segment register loads.

Or you could make pointers HImode, then every pointer is a near pointer.

Gcc only supports one size of pointer, so you either have to make all pointers near pointers or all pointers far pointers. If you need both, you are out of luck. -- Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com

Follow-Ups:
- Re: GCC and memory segments
  - From: Bernd Jendrissek

References:
- GCC and memory segments
  - From: Petar Penchev
- Re: GCC and memory segments
  - From: Bernd Jendrissek

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