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
