MC68HC05C9E Datasheet, PDF (72/106 Pages) Freescale Semiconductor, Inc – Microcontrollers

Instruction Set
11.2.2 Read-Modify-Write Instructions
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.
NOTE
Do not use read-modify-write operations on write-only registers.
Table 11-2. Read-Modify-Write Instructions
Instruction
Mnemonic
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⁾
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.
MC68HC05C9E Advance Information Data Sheet, Rev. 0.1
72
Freescale Semiconductor