Writing, Iguanas, and Electronics

DEC Instruction

The Decrement Instruction operates on counters only, and will effectively subtract 1 from the counter. This instruction does not update any flags.

Decrement Counter

Usage Examples:
        Hex                Mnemonic                      Action

8110      ; DEC PC           PC - 1 -> PC
8120      ; DEC SP           SP - 1 -> SP
8150      ; DEC X             X - 1 -> X

Updates when Executed:

  • The appropriate counter or index register.

Usage Notes

This instruction will only work on counters, and will increment that counter in one clock-cycle.