Preliminary Specifications: Programmed Data Processor Model Three (PDP-3) October, 1960
Indexable Memory Instructions
Add (10 usec.) add x Y Operation Code 40
The new C(AC) are the sum of C(Z) and the original C(AC). The C(Z) are unchanged. The addition is performed with 1's complement arithmetic.
If the sum exceeds the capacity of the Accumulator Register, the overflow flip-flop will be set (see Skip Group instructions).
Subtract (10 usec.) sub x Y Operation Code 4