README.ALTOS

Since COFF-encapsulation is obsolete, this may not be needed anymore.

Return-Path: <jkp@sauna.hut.fi>
Date: Mon, 10 Apr 89 10:13:45 +0300
From: Jyrki Kuoppala <jkp@sauna.hut.fi>
Sender: jkp@sauna.hut.fi
To: info-gcc@prep.ai.mit.edu
Subject: Kernel fix needed for Altos 3068 to get coff-encapsulation working right
Organization: Helsinki University of Technology, Finland.

Here's a description how to fix a kernel bug in Altos 3068 and get
gcc-compiled programs working.

Author: Jyrki Kuoppala (jkp@cs.hut.fi)
Last modified: Mon Apr 10 09:28:40 1989

There's a bug in the Altos 3068 kernel that causes gcc-compiled
programs to fail in certain situations when the machine has a heavy
load and also in some other situations.  The bug exists at least in
SVR 2.2 1.0gT1 and SVR 2.2 1.0e.

If you have source code to your system, apply the following change to
os/exec.c (function gethead):

Change the lines containing

		u.u_exdata.ux_tstart = sizeof(struct naout) +
			sizeof(struct filhd) + (ep->ef.nscns * sizeof(struct scnhdr));

to

		u.u_exdata.ux_tstart = u.u_exdata.ux_txtorg;

If you only have binary, use sdb to find out the address of the
previous lines (on our system it's gethead+0x140) and use your
favourite binary editor to change the bytes '3036 0162 fffc 0002 0280
0000' to '23f9 01fb f4ca 01fb f4c2 6016'.  This may or may not work in
your case, depending on the version of the operating system and the
phase of the moon.

Here's what is just before gethead+0x140 to ease finding out the right place:

0x9224 (gethead+0x122):         23f9 01fb f4ca 01fb f4ce mov.l &0x1fbf4ca.L,&0
x1fbf4ce.L      []
0x922e (gethead+0x12c):         23f9 01fb f4c6 01fb f4ca mov.l &0x1fbf4c6.L,&0
x1fbf4ca.L      []
0x9238 (gethead+0x136):         23f9 01fb f4c2 01fb f4c6 mov.l &0x1fbf4c2.L,&0
x1fbf4c6.L      []

Good luck !

//Jyrki

jkp@cs.hut.fi