3 ms·
> the Honeywell 1800 with two program counters that can go forward or backward Wow! What is the point of that? How is it used?
by TedDoesntTalk 5y ago
> the Honeywell 1800 with two program counters that can go forward or backward
Wow! What is the point of that? How is it used?
- kens 5y agoThe two program counters were first introduced in the National Bureau of Standards' SWAC computer. The idea was that you would use the second program counter for a subroutine call, and then switch back to the first program counter to return to your original code. I don't think anyone really used the backward counting on the program counter; as far as I can tell, that was a side-effect of all the registers being able to auto-increment or auto-decrement.