>Patrick Finnegan wrote:
> I'm trying to get some assembly code to run on my 11/23 by entering it in
> at the ODT, and it seems like I'm having trouble with device I/O
> addresses.
>
> Below is a listing of the assembled code I'm trying - I got the I/O
> address out of a PDP-11 assembly programming book I got from the library.
> Most likely the book was written with a UNIBUS -11 in mind, not a QBUS
> one... is that a problem?
>
> 1 000000 LC=.
> 2 001000 .=LC+1000
> 3
> 4 177564 XSR=177564
> 5 177566 XBUF=177566
> 6
> 7 001000 012767 000110 177566' MOV #110,XBUF
> 8 001006 105767 177564' L1: TSTB XSR
> 9 001012 100375 BPL L1
> 10 001014 012767 000064 177566' MOV #64,XBUF
> 11 001022 105767 177564' L2: TSTB XSR
> 12 001026 100375 BPL L2
> 13 001030 012767 000130 177566' MOV #130,XBUF
> 14 001036 105767 177564' L3: TSTB XSR
> 15 001042 100375 BPL L3
> 16 001044 012767 000060 177566' MOV #60,XBUF
> 17 001052 105767 177564' L4: TSTB XSR
> 18 001056 100375 BPL L4
> 19 001060 012767 000122 177566' MOV #122,XBUF
> 20 001066 105767 177564' L5: TSTB XSR
> 21 001072 100375 BPL L5
> 22 001074 000005 RESET
> 23 001076 000000 HALT
Jerome Fine replies:
I see the string 177564' for XSR and 177566' for XBUF, but the
listing does not have the actual value. Depending on the translation, that
could be the problem.
NORMALLY, in order to avoid problems, I use the code:
001000 112737 000110 177566 MovB #110, _at_#XBUF
which forces the output to 177566 no matter what address is used for the
instruction. Note that I also output ONLY a byte.
Please let us know if this helps.
Sincerely yours,
Jerome Fine
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Received on Mon Sep 16 2002 - 18:48:00 BST