11/45 front panel question
ard at p850ug1.demon.co.uk
Tue Mar 1 18:02:03 CST 2005
> ok, two questions. In at least the docs I have (11/45 service manual, user
> manual, and handbook), I can't find a clear description of how to toggle a
> program into memory.
> I'm assuming that when you enter an address in the front panel switches and
> hit "load addrs", that the data lights aren't supposed to automatically show
> the data value at that location. I'm assuming you must hit "exam" first. Is
> this correct? If not, I'd be autoincrementing and seeing the next data
> value. Can someone give me a good example of just how to enter two or three
Actually, the 11/45 gets this right (and the appropriate bit of
logic/microcode is not trivial). If you EXAM, then DEP, you'll deposit at
the same location (ditto for DEP, then EXAM). It increments the address
between successive DEPs or EXAMs (but not between a DEP and an EXAM or
The easiest way to think of it (and this is what the machine actually
does) is that it increments the address before each EXAM or DEP in a
sequence of identical operations _apart from the first one_.
> words starting at a given location? I think I can figure this out, but I'd
> rather be sure so I don't skip over something that isn't working correctly.
But you don't need to worry about that. Just do this :
Stick the address on the switchs, hit LOAD ADDR
Stick the first word of your program on the switches, hit DEP
Stick the next word on the switches, DEP again
and so on.
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