Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

another pdp8-e "processor flow control" question

3 views
Skip to first unread message

Me

unread,
Jan 8, 2008, 11:52:32 AM1/8/08
to
I'm not familiar with what appears to be a boolean logic symbol in the IOT
section.

What do the upper and lower carat symbols mean?

ex.: c1 ^ c0 or c1 v c0

Rich Alderson

unread,
Jan 8, 2008, 5:19:22 PM1/8/08
to
Me <M...@right-here.com> writes:

^ = Boolean AND
v = Boolean INCLUSIVE OR

--
Rich Alderson "You get what anybody gets. You get a lifetime."
ne...@alderson.users.panix.com --Death, of the Endless

Johnny Billquist

unread,
Jan 8, 2008, 7:03:13 PM1/8/08
to
Rich Alderson skrev:

> Me <M...@right-here.com> writes:
>
>> I'm not familiar with what appears to be a boolean logic symbol in the IOT
>> section.
>
>> What do the upper and lower carat symbols mean?
>
>> ex.: c1 ^ c0 or c1 v c0
>
> ^ = Boolean AND
> v = Boolean INCLUSIVE OR

And those are the mathematical symbols (as close as you can represent them in
ASCII) if I remember right. So it's not really that much PDP-8ish about it.

Johnny

--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol

Me

unread,
Jan 11, 2008, 10:49:19 AM1/11/08
to
Johnny Billquist <b...@update.uu.se> wrote in
news:fm12vb$qft$1...@Tempo.Update.UU.SE:

> Rich Alderson skrev:
>> Me <M...@right-here.com> writes:
>>
>>> I'm not familiar with what appears to be a boolean logic symbol in
>>> the IOT section.
>>
>>> What do the upper and lower carat symbols mean?
>>
>>> ex.: c1 ^ c0 or c1 v c0
>>
>> ^ = Boolean AND
>> v = Boolean INCLUSIVE OR
>
> And those are the mathematical symbols (as close as you can represent
> them in ASCII) if I remember right. So it's not really that much
> PDP-8ish about it.
>
> Johnny
>

you guys are such kidders!
dec used the standard ascii . (dot) for boolean logic and, and + (plus
sign) for boolean logic or, just like everyone else.

please refer me to a web page that has dec documentation showing ^ and v
used as boolean logic and and boolean logic or.

Don North

unread,
Jan 11, 2008, 2:25:43 PM1/11/08
to

Ok, look at the bottom of this page:

http://www.jfc.org.uk/documents/scandoc.php?dir=pdp11%2Fpdp11

'official' DEC documentation

Johnny Billquist

unread,
Jan 11, 2008, 9:04:01 PM1/11/08
to
Me skrev:

Web page??? How could I show you some DEC documentation on a web page, when DEC
didn't produce documentation as web pages.

I have, however, in my hand a copy of the pdp11 programming card. Under
"LEGEND:" you have "Boolean", where you have the mathematical symbols for
boolean operations listed.
^ = AND
v = inclusive OR
v (with a dash through it) = exclusive OR
~ = NOT


How about that?

Digital Equipment Corporation
Maynard Massachusetts July 1975

Me

unread,
Jan 12, 2008, 9:28:19 AM1/12/08
to
Johnny Billquist <b...@update.uu.se> wrote in
news:fm9769$kdh$1...@Tempo.Update.UU.SE:

Great referances from both, many thanks.
It doesn't explain why my document for pdp8/e has . and + in some places
and ^ and v in others. I'll have to figure out where I found it. Probably
on bitsavers or some link I got thru them.
I don't have it with me but basically it reads something like the
following fictional example:


|
__ __ |
____C0^C1______v____C0vC1__
| |
_________v_______ ______v______
| md(5).md(6)=1 | | |
| + | | |
| md(7).(md(11) |
| I->L |
-----------------
|
v
with a box of how a instruction is decoded using . and +
while the ^ and v are used in routing you to the correct path
(instruction group in this case)

0 new messages