Re: fixing i386 gas for 16-bit code

[Ian Lance Taylor <ian@cygnus.com>]

   Date: Wed, 19 Jun 1996 00:41:40 -0500
   From: VaX#n8 <vax@linkdead.paranoia.com>

   I was wondering if you know how hard it would be (for me) to fix gas
   to create 16-bit code properly, especially in the case of SIB (scaled
   indexed based) addressing modes on the i386.

I don't know much about the i386 myself, so I'm CC'ing your note to
the gas developers list, gas2@cygnus.com.  Perhaps somebody on the
list will have some useful information.

   I have to hand code things like:

   movb 1(%si), %dh

   because it flubs the Mod-R/M byte.

   Another cool thing would be 8-bit offset addressing.  Coding all this by
   hand is hair-pulling material.  It is so ugly I chose not to do it :)

I used to hand code stuff when I was a kid, but it's pretty horrifying
to think that anybody still has to do it.

I believe that there are some 16 bit i386 assemblers out there.

   Would I have to learn bfd?  It confused the heck outta me when I looked
   at the bfd source last time :-/

You shouldn't have to look at BFD for this sort of thing.

Ian