2.2.25 (3) DEC (L)
DEC (DECrement)
Decrement
Operation
ERd – 1
→
ERd
ERd – 2
→
ERd
Assembly-Language Format
DEC.L #1,
ERd
DEC.L #2,
ERd
Operand Size
Longword
Condition Code
H: Previous value remains unchanged.
N: Set to 1 if the result is negative; otherwise
cleared to 0.
Z:
Set to 1 if the result is zero; otherwise
cleared to 0.
V: Set to 1 if an overflow occurs; otherwise
cleared to 0.
C: Previous value remains unchanged.
I
UI
H
U
N
Z
V
C
—
—
—
—
↕
↕
↕
—
Description
This instruction subtracts the immediate value 1 or 2 from the contents of a 32-bit register ERd
(destination register) and stores the result in the 32-bit register ERd.
Available Registers
ERd: ER0 to ER7
Operand Format and Number of States Required for Execution
Notes
An overflow is caused by the operations H'80000000 – 1
→
H'7FFFFFFF, H'80000000 – 2
→
H'7FFFFFFE, and H'80000001 – 2
→
H'7FFFFFFF.
Instruction Format
1st byte
2nd byte
3rd byte
4th byte
Register direct
DEC.L
#1, ERd
1
B
7
0 erd
2
Register direct
DEC.L
#2, ERd
1
B
F
0 erd
2
No. of
States
Addressing
Mode
*
Mnemonic
Operands
81