How CPU's work (was Re: Hi, I'm new...)

[Pete Turnbull]

On Aug 7 2006, 15:14, Roy J. Tellason wrote:

> Well,  that one is a 10 MHz part while the 68000 I have is I think an
8 MHz
> part,  which is a bigger increase than that,  but the clock driving
the thing
> would need to be changed too,  and I don't think they have exactly
the same
> pinout,  though it's been a really long time since I looked at that
material.

They do have the same pinout, and a 68010 is a drop-in replacement for
a 68000.  Except they stopped making it ages ago, and it's easier to
get a 68000 than a 68010.  The 68010 fixed the problem of not being
able to recover from an interrupted instruction, handles double bus
faults correctly, added a few vectors, made the exception vectors
relocatable, and fixed the problem that getting back to supervisor mode
from user mode wasn't privileged in the original 68000 (which made a
nonsense of any protection schemes).  However, it has some other minor
differences that mean it may not be 100% software compatible with a
68000, for example the revised exception stack frames.  I'd have to dig
out some very old course notes to tell you more.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York