Writing, Iguanas, and Electronics

INC Instruction

The Increment Instruction operates on counters only, and will effectively add +1 to the counter. This is a separate instruction from the ALU DEC, which operates on the Data Bus and stores the incremented result in the OCR. The ALU DEC will update the flags, this one will not.

Increment Counter Instruction

Usage Examples:
        Hex                Mnemonic                      Action

8010      ; INC PC           PC + 1 -> PC
8020      ; INC SP           SP + 1 -> SP
8050      ; INC X             X + 1 -> X

Updates when Executed:

  • The appropriate counter or index register.