Path: utzoo!attcan!uunet!mcsun!ukc!harrier.ukc.ac.uk!dac
From: dac@ukc.ac.uk (David Clear)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: What do the Bombs mean?
Message-ID: <5600@harrier.ukc.ac.uk>
Date: 4 Oct 90 10:40:30 GMT
References: <`$R%X?_@rpi.edu>
Reply-To: dac@ukc.ac.uk (David Clear)
Organization: Computing Lab, University of Kent at Canterbury, UK.
Lines: 31

In article <`$R%X?_@rpi.edu> onders@degas.ipl.rpi.edu (Timothy E. Onders) writes:
>In particular, what do 3 bombs mean? Does anyone have a list of the
>different bombs?  I used to have one but I can not find it now.

This seems to be a regular question so I'm posting this list.

Bombs	Meaning				Possible cause
  2	Bus error			Access non-existent memory
  3	Address error			Word/Long access to an odd address
  4	Illegal Instruction		Bad opcodes (JMPing into data!)
  5	Divide by zero			Left as an exercise for the reader :-)
  6	CHK Instruction			Ditto
  7	TRAPV Instruction		Ditto
  8	Priviledge violation		Priviledge instructions in user mode
  9	Trace				Trace!
 10	Line A Trap			$Axxx opcode - used be system
 11	Line F Trap			$Fxxx opcode - used by system
 >11	Unassigned/Interrupt/Trap	Bad interrupt/trap

 On my old ST (1986), addresses up to $3fffff (4Mb) are accepted even if
 the memory doesn't actually exist - so you may not get a bus error
 even if you're expecting one.

 Hope this helps alot of people.

 Dave.
-- 
% cc life.c                      | David Clear dac@ukc.ac.uk +44 227 764000x7592
% a.out                          | Local Area Networks, Computing Laboratory,
Segmentation fault (core dumped) | University of Kent, Canterbury, England.
>>> Kernel R0M. His Mission: To rid the world of wobbly ZX-81 16K RAM packs. <<<