Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ncis.llnl.gov!ncis!helios.ee.lbl.gov!pasteur!ucbvax!UOTTAWA.BITNET!451061
From: 451061@UOTTAWA.BITNET (Valentin Pepelea)
Newsgroups: comp.sys.amiga.tech
Subject: Exception Processing
Message-ID: <8901190614.AA18557@jade.berkeley.edu>
Date: 19 Jan 89 05:15:53 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 29


In message 3703@crash.cts.com, billk@pnet01.cts.com (Bill Kelly) writes:
> Well, I guess that about wraps it up for Amiga Interrupts...
> Next question, please?  :-)

What about about exception processing, oh venerable Guru? I need to
simulate a 680x0 coprocessor interface, and therefore need to do some
F-line instruction emulation. I *have* to use the autovectors rather
than the Exec interrupt facility, so please don t suggest an alternative.

The question is, what happens to the 68000 then? I understand that a7
gets switched with the exception stack pointer. Now, is my Amiga still
multitasking, can I call an AmigaDOS function in order load a file from
disk?

If we are still multitasking, what if another task encounters an F-line
instruction simoultaneously? Will then both tasks have their A7 register
loaded with the same exception stack pointer?

The problem I have is that I will absolutely need to do some disk I/O
during exception processing.

                                                    Valentin
_________________________________________________________________________
"An  operating  system  without         Name: Valentin Pepelea
 virtual memory is an operating         Phone: (613) 233-1821
 system without virtue."                Bitnet: 451061@uottawa
                                        Usenet: Look at the header
         - Ancient Inca Proverb         Planet: Earth