Timeline for Arithmetic operations on multiple words on the PDP-8
Current License: CC BY-SA 3.0
3 events
| when toggle format | what | by | license | comment | |
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| Oct 22, 2016 at 1:53 | comment | added | George Phillips |
Doesn't work, unfortunately. After the first word you only need to subtract 1 if there's a borrow or 0 if not. The extra +1 is only needed on the first word. So what is needed is conversion of L to AC = -1 or 0. Best I could come up with takes two instructions: RAL : CMA IAC so it isn't any shorter than the SZL solution.
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| Oct 21, 2016 at 18:13 | comment | added | George Phillips | Clever stuff. Can't quite convince myself that carry works in all instances. I'll have to try testing this later to see. And, for that matter, I should test my proposed subroutines. | |
| Oct 21, 2016 at 6:15 | history | answered | dirkt | CC BY-SA 3.0 |