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assemblypdp-11

clock on pdp-11

I'm a little bit confused about simple program which I wrote, can You please explain why it quits after printing only one character, I expected it will print me character every 5 seconds, thanks in advance

tks = 177560
tkb = 177562
tps = 177564
tpb = 177566
lcs = 177546
. = torg + 2000

main:   mov #main, sp

        mov #clock, @#100  ; vector interrupt of the clock 100-102
        mov #300, @#102    ; 

        mov #100, @#lcs    ; here I enable interrupt-enable of the clock

prog:   clr r0             ; here endless loop
        beq prog
        halt

clock:  inc count
        cmp count, timeout
        bne clk_end
        clr count
        mov #'*, @#tpb
clk_end:rti

. = torg + 3000
timeout: .word 300000
count: .word 0
Solution

  • This is surely a simulator-related problem, since I tried to run you code, and it works fine!

    Are you by chance a student at the Technion?