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PIC18F87J10 Datasheet, PDF (327/394 Pages) Microchip Technology – 64/80-Pin High-Performance, 1-Mbit Flash Microcontrollers with nanoWatt Technology | |||
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PIC18F87J10 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 â [ 0, 1, 2 ]
FSRf â k â FSRf
None
1110 1001 ffkk kkkk
The 6-bit literal âkâ is subtracted from
the contents of the FSR specified
by âfâ.
1
1
Q2
Read
register âfâ
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:
SUBULNK k
0 ⤠k ⤠63
FSR2 â k â FSR2
(TOS) â PC
None
1110 1001
11kk
kkkk
Description:
The 6-bit literal âkâ 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 â11â); it operates only on FSR2.
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Decode
Q2
Read
register âfâ
Q3
Process
Data
Q4
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)
 2005 Microchip Technology Inc.
Advance Information
DS39663A-page 325
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