23 Jun
2004
23 Jun
'04
10:51 a.m.
On Wed, 23 Jun 2004, Tony Duell wrote:
And presumably stage 3 is to grab
a VAX11/7xx printset, figure out the
microinstruction word, then disassemble the appropriate bit of the
microocde and understand how it works. Actually, I've never done this for
VAX microcode, I did comment the entire HP98x0 calculator CPU micorocode
source, though (256 locations of 28 bits each).
I think that we are getting more than a little past what I can
realistically teach beginners in one semester.
Ten or twenty years ago, we could add followup, more advanced
classes into the schedule. Now I'm in a [losing] fight for
survival, trying to keep programming classes alive. If they
ask me to teach Microsoft Weird again, I might not survive.
Well, you might actually be able to show them the same
simple
program for the IBM-1401, PDP-8, PDP-10, PDP-11, VAX, ... to
get an idea of the different architectures. Something simple,
like calculating a polynomial (VAX = 1 instruction,
PDP-8=aaak! You expect me to type that in?).
Presumably for stage two you have
them explain
why the POLYx instructions (which are in microcode
in the early VAXen) were subsetted out later on.