Datasheet

 2010-2012 Microchip Technology Inc. DS39977F-page 529
PIC18F66K80 FAMILY
SUBFSR Subtract Literal from FSR
Syntax: SUBFSR f, k
Operands: 0
 k  63
f
 [ 0, 1, 2 ]
Operation: FSRf – k
 FSRf
Status Affected: None
Encoding:
1110 1001 ffkk kkkk
Description: The 6-bit literal ‘k’ is subtracted from
the contents of the FSR specified
by ‘f’.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example:
SUBFSR 2, 23h
Before Instruction
FSR2 = 03FFh
After Instruction
FSR2 = 03DCh
SUBULNK Subtract Literal from FSR2 and Return
Syntax: SUBULNK k
Operands: 0
 k  63
Operation: FSR2 – k
 FSR2,
(TOS)
PC
Status Affected: None
Encoding:
1110 1001 11kk kkkk
Description: 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
Operation
No
Operation
No
Operation
No
Operation
Example:
SUBULNK 23h
Before Instruction
FSR2 = 03FFh
PC = 0100h
After Instruction
FSR2 = 03DCh
PC = (TOS)