MC68HC705JJ7 Datasheet, PDF (128/164 Pages) Freescale Semiconductor, Inc – Microcontrollers

Instruction Set
14.3.2 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 14-2. Read-Modify-Write Instructions
Instruction
Arithmetic Shift Left (Same as LSL)
Arithmetic Shift Right
Bit Clear
Bit Set
Clear Register
Complement (One’s Complement)
Decrement
Increment
Logical Shift Left (Same as ASL)
Logical Shift Right
Negate (Two’s Complement)
Rotate Left through Carry Bit
Rotate Right through Carry Bit
Test for Negative or Zero
Mnemonic
ASL
ASR
BCLR⁽¹⁾
BSET⁽¹⁾
CLR
COM
DEC
INC
LSL
LSR
NEG
ROL
ROR
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.
MC68HC705JJ7 • MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
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Freescale Semiconductor