Loop program for the PDP-11
I have used this loop program on both the PDP-11\23 and the 11\34 and assum it will work on just about any PDP useing just the built in ODT code.
1000 005000 CLR R0
1002 12701 MOV #177564 to R1
1006 105711 Loop TSTB R1
1010 100376 BPL Loop
1012 110061 MOVB R0, 2(R1)
1016 005200 INC R0
1020 000137 JMP #1006
Use L to load the starting address, D to deposit to that address and E to examine the contents of that address. When your depositing new data in each address you only have to enter the starting address and the ODT will advance to the next memory location on its own, then go back to location 1000 and enter G for go.
Used this little loop on a number of systems and its always fun!
ODT or Console Emulator Functions
In most of the stuff I have played around with the ODT or Console Emulator are built into the Bios of the system, so getting out of the Boot prompt dumps you into that system. Remember the emulator only operates in Octal! And all addresses must be even.
L Load address
E Examine address
D Deposits entered data into loaded or examined address
S Start at loaded address
DL11-W Serial Line Unit Fun and games!
The DL11 Unibus communications card along with any of the Qbus or second source communications cards will always have the same addresses for the input and output register, 777560 for the receiver (Keyboard) and 777566 for the send (display).
By entering L 777560 and then E you can see the last character sent from the CON keyboard to the system.
By entering L 777566 and then D you can push that out the transmit buffer and see it displayed on the CON
I know this is stupid but hours can be wasted this way, remember that the numbers in the registers will be in Octal.
YouTube Video of loop on PDP-11/23
YouTube Video of loo on PDP-11/34
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