PiDP-8

History:

The PDP-8, developed in 1964, was the first mass produced minicomputer. It was developed at the DEC plant in Reading, England. It sold for about $18,500 to $20,000.

The PDP-8 was a 16-bit machine. The PDP-8 was also known as the "Classic 8." It used the newly announced R Series logic.

So you've built a PiDP-8, now what? Here are some things I've learned.

When you first boot the PiDP-8 you will see something like the following:

PDP-8 simulator V4.0-0 Current        git commit id: 4e0450cf

PiDP-8/I pi4-gpio-hack:id[bd10d4dde2] [pi4b] [ils] [stdpcb] [gpio] [rt]Loading OS/8 from the RK05 cartridge disk...


PiDP-8/I pi4-gpio-hack:id[bd10d4dde2] - OS/8 V3D - KBM V3Q - CCL V1F

Configured by pi@raspberrypi on 2020.02.18 at 12:35:20 PST


Restart address = 07600


Type:

    .DIR                -  to get a list of files on DSK:

    .DIR SYS:           -  to get a list of files on SYS:

    .R PROGNAME         -  to run a system program

    .HELP FILENAME      -  to type a help file

If you type DIR at the prompt you will get a listing of files, which are games and their supporting files. Those games ending in .BA (meaning BASIC) can be run by typing:

Wumpus

.R BASIC

NEW OR OLD--OLD


FILE NAME--RKB0:WUMPUS   [or whatever game file]

RUN


However, Chess is run by just typing:


Chess

.R CHESS

    

Finally about Adventure. 

.R FRTS

*ADVENT$          ⇠ $ = Escape keypress



Run Adventure

.R RFTS 

*ADVENT$       ⇠ The $ sign is produced by pressing the Esc key


to quit

SUSPEND

to save game

.SA SYS ADV

to re-run

.R ADV

If you run into errors or issues running Adventure then what you need to do is restore the ADVENT.LD file.  In order to restore its:

From within the simulator, press Ctrl-E to get out to the SIMH command prompt, then follow this script:

sim> att dt0 /opt/pidp8i/share/media/os8/subsys/advent.tu56

sim> cont

.COPY DSK:<DTA0:ADVENT.LD


Manually program in a timer 

Do the following entry:

First we choose an address. The address can be arbitrary, but let's enter 10, then  Load Add.

Enter the accumulator command. 7001, Dep.

Delay instruction to slow down: 2034

Jump back to previous instruction for delay: 5011

2035

5013

2036

5015

2037

5017

Jump to first instruction: 5010

Now let's enter the halt command. 7402, Dep.

So we can then go back to the address, push on Single Step, Start and Cont to see each step.