
Instruction Set
Instruction Types
MC68HC05E5 — Rev. 1.0
General Release Specification
MOTOROLA
Instruction Set
111
NON-DISCLOSURE
AGREEMENT
REQUIRED
13.4.2 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.
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 be-
cause it does not write a replacement value.
Table 13-2. 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)
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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