20 Oct
1999
20 Oct
'99
4:39 a.m.
allisonp(a)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(a)mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97