Skip to main content

All Questions

Tagged with
11 votes
2 answers
645 views

IMPI Instruction set: is there any reference?

I've had an IBM 9404 B-10 for some time and I'm curious about its assembly language. I'm fully aware the AS lines were designed with portability in mind as much IBM didn't seem to provide assembly ...
Borg Drone's user avatar
14 votes
2 answers
612 views

What is the purpose of the "difference of absolute values" instruction?

The IBM NORC computer, among others, had an arithmetic instruction computing the difference of the absolute values of its operands (|x|-|y|, see NORC Programming Manual, page 11, opcode 28), which ...
Leo B.'s user avatar
  • 19.4k
29 votes
3 answers
4k views

Why does an instruction include the address of the next instruction on the IBM 650?

The IBM 650 seems to be a load-store machine. One advantage of a load-store machine is that the instruction can be shorter because there's less pressure to pack more information into it. But the IBM ...
Omar and Lorraine's user avatar