PIC18F2420/2520/4420/4520
24.2.2
EXTENDED INSTRUCTION SET
ADDFSR
Add Literal to FSR
ADDULNK
Add Literal to FSR2 and Return
Syntax:
ADDFSR f, k
Syntax:
ADDULNK k
Operands:
0 ≤ k ≤ 63
f ∈ [ 0, 1, 2 ]
FSR(f) + k → FSR(f)
None
Operands:
Operation:
0 ≤ k ≤ 63
FSR2 + k → FSR2,
(TOS) → PC
None
Operation:
Status Affected:
Encoding:
Status Affected:
Encoding:
1110
1000
ffkk
kkkk
1110
1000
11kk
kkkk
Description:
The 6-bit literal ‘k’ is added to the
contents of the FSR specified by ‘f’.
Description:
The 6-bit literal ‘k’ is added to the
contents of FSR2. A RETURNis then
executed by loading the PC with the
TOS.
Words:
1
1
Cycles:
The instruction takes two cycles to
execute; a NOPis performed during
the second cycle.
This may be thought of as a special
case of the ADDFSRinstruction,
where f = 3 (binary ‘11’); it operates
only on FSR2.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to
FSR
ADDFSR 2, 23h
Example:
Words:
Cycles:
1
2
Before Instruction
FSR2
After Instruction
FSR2
=
03FFh
0422h
Q Cycle Activity:
Q1
=
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to
FSR
No
No
No
No
Operation
Operation
Operation
Operation
ADDULNK 23h
Example:
Before Instruction
FSR2
PC
=
=
03FFh
0100h
After Instruction
FSR2
PC
=
=
0422h
(TOS)
Note:
All PIC18 instructions may take an optional label argument preceding the instruction mnemonic for use in
symbolic addressing. If a label is used, the instruction syntax then becomes: {label} instruction argument(s).
DS39631E-page 310
© 2008 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
