PIC18F258 MICROCHIP [Microchip Technology], PIC18F258 Datasheet - Page 316

• Manufacturer Part Number: PIC18F258
• Description: High Performance, 28/40-Pin Enhanced FLASH Microcontrollers with CAN
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18FXX8
SUBWFB
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example 1:
Example 2:
Example 3:
DS41159B-page 314
Q Cycle Activity:
Before Instruction
After Instruction
Before Instruction
After Instruction
Before Instruction
After Instruction
Decode
REG
W
C
REG
W
C
Z
N
REG
W
C
REG
W
C
Z
N
REG
W
C
REG
W
C
Z
N
Q1
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
register ’f’
Subtract W from f with Borrow
[ label ] SUBWFB
0
d
a
(f) – (W) – (C)
N, OV, C, DC, Z
Subtract W and the carry flag (bor-
row) from register 'f' (2’s complement
method). If 'd' is 0, the result is stored
in W. If 'd' is 1, the result is stored
back in register 'f' (default). If ’a’ is 0,
the Access Bank will be selected,
overriding the BSR value. If ’a’ is 1,
then the bank will be selected as per
the BSR value (default).
1
1
SUBWFB
SUBWFB REG, 0, 0
SUBWFB
Read
0101
Q2
f
0x19
0x0D
0x01
0x0C
0x0D
0x01
0x00
0x00
0x1B
0x1A
0x00
0x1B
0x00
0x01
0x01
0x00
0x03
0x0E
0x01
0xF5
0x0E
0x00
0x00
0x01
[0,1]
[0,1]
255
10da
REG, 1, 0
REG, 1, 0
(0001 1001)
(0000 1101)
(0000 1011)
(0000 1101)
; result is positive
(0001 1011)
(0001 1010)
(0001 1011)
; result is zero
(0000 0011)
(0000 1101)
(1111 0100)
; [2’s comp]
(0000 1101)
; result is negative
Process
Data
Q3
dest
ffff
f [,d [,a]]
destination
Write to
Q4
ffff
SWAPF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example:
Q Cycle Activity:
Before Instruction
After Instruction
Decode
REG
REG
Q1
=
=
register ’f’
Swap f
[ label ] SWAPF f [,d [,a]]
0
d
a
(f<3:0>)
(f<7:4>)
None
The upper and lower nibbles of reg-
ister ’f’ are exchanged. If ’d’ is 0, the
result is placed in W. If ’d’ is 1, the
result is placed in register ’f’
(default). If ’a’ is 0, the Access
Bank will be selected, overriding
the BSR value. If ’a’ is 1, then the
bank will be selected as per the
BSR value (default).
1
1
SWAPF
Read
0011
Q2
0x53
0x35
f
[0,1]
[0,1]
2002 Microchip Technology Inc.
255
REG
10da
dest<7:4>,
dest<3:0>
Process
Data
Q3
ffff
destination
Write to
Q4
ffff