PIC18F45K80-I Datasheet, PDF (529/622 Pages) Microchip Technology – 28/40/44/64-Pin, Enhanced Flash Microcontrollers with ECAN and nanoWatt XLP Technology

PIC18F66K80 FAMILY
SUBFSR
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
Q1
Decode
Subtract Literal from FSR
SUBFSR f, k
0  k  63
f  [ 0, 1, 2 ]
FSRf – k  FSRf
None
1110 1001 ffkk kkkk
The 6-bit literal ‘k’ is subtracted from
the contents of the FSR specified
by ‘f’.
1
1
Q2
Read
register ‘f’
Q3
Process
Data
Q4
Write to
destination
Example:
SUBFSR 2, 23h
Before Instruction
FSR2 = 03FFh
After Instruction
FSR2 = 03DCh
SUBULNK
Subtract Literal from FSR2 and Return
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
SUBULNK k
0  k  63
FSR2 – k  FSR2,
(TOS) PC
None
1110 1001 11kk kkkk
The 6-bit literal ‘k’ is subtracted from the
contents of the FSR2. A RETURN is then
executed by loading the PC with the
TOS.
The instruction takes two cycles to
execute; a NOP is performed during the
second cycle.
This may be thought of as a special case
of the SUBFSR instruction, where f = 3
(binary ‘11’); it operates only on FSR2.
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
No
No
No
No
Operation Operation Operation Operation
Example:
SUBULNK 23h
Before Instruction
FSR2 = 03FFh
PC
= 0100h
After Instruction
FSR2 =
PC
=
03DCh
(TOS)
 2010-2012 Microchip Technology Inc.
DS39977F-page 529