Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!apple!well!sjm
From: sjm@well.UUCP (Stephen Moehle)
Newsgroups: comp.sys.amiga.tech
Subject: Help with Supervisor State
Keywords: supervisor state
Message-ID: <10510@well.UUCP>
Date: 28 Jan 89 07:37:53 GMT
Distribution: comp
Lines: 34


    Well, since no one saw fit to help me out with using the 68851 on the
A2620 board, I have been blindly trying to figure it out.  I actually think
that I can get the 68851 to do what I want, but I cannot even try it.  Since
PMOVE is a privileged instruction, I have to get the 68020 into the supervisor
state first.  I have tried the following test:

#include <stdio.h>

long SuperState();

int i = 0;

main()
{
    long stack;

    stack = SuperState();
    i = 55;
    UserState(stack);
    printf("%d\n", i);
}

    The machine always GURUs with exception #3, Address Error, whether I run
it on the 68020 or the 68010.  I think it is dying in SuperState().  At least
the debugger never gets to the breakpoint at "i = 55".  What am I doing wrong?
How can I get the machine into supervisor state?  Please.

    My system consists of an A2000, A2620, WorkBench 1.3, 1.2 ROMS, and
Manx C 3.6.  I also run SetPatch.  Thanks.

Stephe
{ucbvax,pacbell,hplabs}!well!sjm     or     well!sjm@lll-winken.arpa
"You heard the weirdo man.  What is truth?"