11/45 front panel question

Paul Koning pkoning at equallogic.com
Tue Mar 1 15:40:34 CST 2005


>>>>> "Jay" == Jay West <jwest at classiccmp.org> writes:

 Jay> ok, two questions. In at least the docs I have (11/45 service
 Jay> manual, user manual, and handbook), I can't find a clear
 Jay> description of how to toggle a program into memory.

 Jay> I'm assuming that when you enter an address in the front panel
 Jay> switches and hit "load addrs", that the data lights aren't
 Jay> supposed to automatically show the data value at that
 Jay> location. I'm assuming you must hit "exam" first. Is this
 Jay> correct? If not, I'd be autoincrementing and seeing the next
 Jay> data value. Can someone give me a good example of just how to
 Jay> enter two or three words starting at a given location? I think I
 Jay> can figure this out, but I'd rather be sure so I don't skip over
 Jay> something that isn't working correctly.

The way it works is this:

- Load address sets the address you're working from
- Exam shows what's in the working address
- Deposit changes the contents at the working address
- If you do exam and exam again, then the second exam increments the
  working address first.
- Ditto on deposit and deposit
- However, exam then deposit don't change the working address

So, for example
- load address 1000
- exam exam exam
shows you locations 1000, 1002, 1004, and
- load address 1000
- exam
- deposit 20
looks at location 1000, then changes location 1000 (NOT 1002) to 20.

 Jay> Second, since it's been over 20 years since I did any MACRO-11
 Jay> programming, could someone post a simple few line machine code
 Jay> program I can enter and run to see if the machine will even go
 Jay> into execute mode correctly. Maybe something that just adds two
 Jay> constants and stores them in another memory location.

Here's a lovely hack -- a one instruction program.  Load it at the
last location of your memory.  For example, in a machine with 28 kW or
more, load it into 157776.  The instruction word is 014747.  Deposit
it and start it.  If the machine is working right, you'll end up with
014747 in all your memory from 157776 down to zero.

An exercise for the student is why this is so.

      paul




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