Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!sdd.hp.com!decwrl!shelby!neon!kaufman
From: kaufman@Neon.Stanford.EDU (Marc T. Kaufman)
Newsgroups: comp.sys.m68k
Subject: Re: Interpretation of 68000 Function Code Outputs
Message-ID: <1990Oct3.160343.401@Neon.Stanford.EDU>
Date: 3 Oct 90 16:03:43 GMT
References: <1057@tharr.UUCP>
Organization: Computer Science Department, Stanford University
Lines: 20

In article <1057@tharr.UUCP> chris@tharr.UUCP (Chris Allen) writes:

-Can anyone explain the interpretation of the function code
-outputs on the 68000 (FC0-FC2). The manual says that they can
-represent

-User Program
-User Data
-Supervisor Program
-Supervisor Data
-[.. some others which are not important]

-What is the difference between program and data? 

"Program" is instruction fetches.  Data is anything else.  But I beg to differ
with you about the unimportance of other codes.  In particular, FC7 is the
interrupt acknowledge cycle.  You want to make sure all memory and IO
addressing is turned off, especially if you have memory-mapped IO registers.

Marc Kaufman (kaufman@Neon.stanford.edu)