PDP 11/45 light chaser

[Jim Beacon]

Jay,

this is the one I used:

Location    Content Op-code            comment
001000    012700    mov #1,r0        load ro with 1
001002    000001
001004    006100    rol                    rotate r1 left
001006    012701    mov delay r1    load register r1 with delay
001010    007777    delay
001012    005301    dec r1                decrement register 1
001014    001376    bne -2                continue to decrement r1 until
r1=0
001016    000772    br -12                back to 001002 (dec r0)

it's not elegant, but you do get to see the lamps light, you can change the
speed by altering the "delay" value. It doesn't work to well, as the data
display will show the load of r1 as well.

Yo should be able to alter it to put the lght chaser into the console
display register (you'll have to re-calculate the value of the final
branch - it will need an extra two memory loactions, one for the mov display
register instruction, and one for the location of the register). I haven't
got this to work on my 11/45, as I get a memory address error when I try to
write to the display register, though I'm told I should be able to write to
it - I think there is a processor fault lurking in there somewhere, or
possibly a fault in the memory management module, though this is less
likely, as I can read and write to the DL11W serial port.

Jim.
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