Path: utzoo!attcan!uunet!xavax!jat
From: jat@xavax.com (John Tamplin)
Newsgroups: comp.sys.m88k
Subject: Re: Some basic questions regarding use of 88000
Message-ID: <1990Jul26.023748.4148@xavax.com>
Date: 26 Jul 90 02:37:48 GMT
Organization: Xavax
Lines: 23

In article <1990Jul24.032416.13340@cec1.wustl.edu> kapoor@wuee1.wustl.edu (Sanjay Kapoor) writes:
>Here are a few basic questions regarding the 88000.
>
>Q1: How does the 88000 handle interrupts? the sparc architecture helps
>reduce the overhead for critical interrupts by reserving a register window for
>trap handling. What about M88000?

At exception time, the processor state is saved in shadow registers.  The
exception handler can examine them, correct the problem, and resume execution
without any memory accesses if the exception is simple.  Running Unix, though,
the overhead can be quite large.

>Q2: What precautions are need to interface to a standard bus eg VME? Is this
>bus (VME) the best option?

You really don't want your memory on VME.  You should be able to get quite a
bit faster throughput with memory sitting directly on the MBus.  As far as
peripherals, well VME is one of several choices each with tradeoffs.

-- 
John Tamplin						Xavax
jat@xavax.COM						2104 West Ferry Way
...!uunet!xavax!jat					Huntsville, AL 35801