68HC05 Instruction Set — Part 2
ADD add to the accumulator ADC add to the accumulator with carry SUB subtract from the accumulator SBC subtract from the accumulator with borrow MUL multiply the accumulator by the index register NEG negate (take the 2’s complement of) a memory location NEGA negate (take the 2’s complement of) the accumulator NEGX negate (take the 2’s complement of) the index register
Notes:
The ADD and SUB instructions, respectively, add or subtract a byte to or from the accumulator. ADC and SBC do the same but with a carry or borrow if the condition code register carry bit (C) is set.
The MUL instruction performs an unsigned multiply of the index register (X) and the accumulator (A). The result is stored with the upper byte in X and the lower byte in A.
NEG, NEGA, and NEGX take the two’s complement of a memory location, the accumulator, or the index register. The two’s complement of a number is zero minus that number.