allisonp_at_world.std.com wrote:
[stuff deleted]
> The tricks were sometime burried in things like open collector wired OR
> logic that made system like the PDP-8E rather than tristate.
I'm convinced Edson DeCastro has a major hard-on for using OC wire or/wire and
logic; it shows up all over the Nova. Debugging is a real joy; start clipping
leads until you find the problem :-(
[snip]
> We, having done that with 290x stuff the 8080 was weakest in not having an
> orthoginal instruction set. the best example was LXI SP, load SP with
> immediate but, there was no store SP at all. To save the SP(stack
> pointer) you had to save HL pair, Load it with 0000, add SP,HL and then
> you could store the result from the HL pair. YUCK! With holes like that
> filled the z80 really was an improvement.
Absolutly!
Chris
--
Chris Kennedy
chris_at_mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97
Received on Wed Oct 20 1999 - 11:39:46 BST