"Nobody teaches assembly language"

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Wed Jun 23 17:02:49 2004

>
> > 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.

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).

-tony
Received on Wed Jun 23 2004 - 17:02:49 BST