17 Apr
2018
17 Apr
'18
11:52 a.m.
On 04/17/2018 02:21 PM, Chuck Guzis via cctalk wrote:
How many started coding for a machine writing machine
code?
I recall that the IBM 1620 SPS coding forms had two sides--one for
coding assembly (SPS); the other labeled "IBM 1620 Absolute Coding
System". Basically a form with the first 5 positions reserved for the
address, 2 positions for the opcode and 5 positions each for the P and Q
addresses.
You could enter the code from the form right into the console typewriter
or punch it on a keypunch. If you were a real hard-case, you didn't
bother with coding forms, you sat down at the typewriter and did
everything from memory, mentally keeping track of storage addresses and
what referenced them.
Do this for a while and disassembly is easy. After all, you'll have all
of the instructions and their opcodes committed to memory.
I believe that I can still do this for 8080 code, in spite of my
deteriorating wetware.
Well, the first programming I learned was Autocoder on the IBM 1401.
Our instructor gave us a simple project (80/80 Print). Had us write it in
Autocoder and verify that it worked. Then we had to optimize it to
reduce it to fit on a single punched card.? That was done by tweaking
the machine code output by the Autocoder "compiler".? I still have mine
around here somewhere.
bill