PIC18F2450 MICROCHIP [Microchip Technology], PIC18F2450 Datasheet - Page 259

• Manufacturer Part Number: PIC18F2450
• Description: 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

SUBFSR
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example:
© 2006 Microchip Technology Inc.
Q Cycle Activity:
Before Instruction
After Instruction
Decode
FSR2
FSR2
Q1
=
=
register ‘f’
Subtract Literal from FSR
SUBFSR f, k
0
f
FSRf – k
None
The 6-bit literal ‘k’ is subtracted from
the contents of the FSR specified by
‘f’.
1
1
SUBFSR 2, 23h
Read
1110
Q2
03FFh
03DCh
[ 0, 1, 2 ]
k
63
1001
FSRf
Process
Data
Q3
ffkk
destination
Advance Information
Write to
kkkk
Q4
SUBULNK
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
Words:
Cycles:
Example:
Q Cycle Activity:
Before Instruction
After Instruction
Operation
Decode
No
FSR2
PC
FSR2
PC
PIC18F2450/4450
Q1
Subtract Literal from FSR2 and Return
SUBULNK k
0
FSR2 – k
(TOS)
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.
1
2
1110
=
=
=
=
k
register ‘f’
Operation
SUBULNK 23h
Read
63
No
Q2
03FFh
0100h
03DCh
(TOS)
PC
FSR2
1001
Operation
Process
Data
No
Q3
DS39760A-page 257
11kk
destination
Operation
Write to
kkkk
No
Q4