Motorola MC68HC05RC8 User Manual

Instruction Set

Instruction Types

MC68HC05RC16 — Rev. 3.0

General Release Specification

MOTOROLA

Instruction Set

91

These instructions read a memory location or a register, modify its
contents, and write the modified value back to the memory location or to
the register.

Do not use read-modify-write operations on write-only registers.

1. Unlike other read-modify-write instructions, BCLR and

BSET use only direct addressing.

2. TST is an exception to the read-modify-write sequence

because it does not write a replacement value.

Arithmetic Shift Left (Same as LSL)

ASL

Arithmetic Shift Right

ASR

Bit Clear

BCLR

(1)

Bit Set

BSET

(1)

Clear Register

CLR

Complement (One’s Complement)

COM

Decrement

DEC

Increment

INC

Logical Shift Left (Same as ASL)

LSL

Logical Shift Right

LSR

Negate (Two’s Complement)

NEG

Rotate Left through Carry Bit

ROL

Rotate Right through Carry Bit

ROR

Test for Negative or Zero

TST

(2)