PIC18F2220 MICROCHIP [Microchip Technology], PIC18F2220 Datasheet - Page 294

• Manufacturer Part Number: PIC18F2220
• Description: 28/40/44-Pin High-Performance, Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F2220/2320/4220/4320
SUBWFB
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
DS39599C-page 292
Q Cycle Activity:
Decode
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
Read
0101
Q2
f
[0,1]
[0,1]
255
10da
Process
Data
Q3
dest
ffff
f [,d [,a]]
destination
Write to
Q4
ffff
Example 1:
Example 2:
Example 3:
Before Instruction
After Instruction
Before Instruction
After Instruction
Before Instruction
After Instruction
REG
W
C
REG
W
C
Z
N
REG
W
C
REG
W
C
Z
N
REG
W
C
REG
W
C
Z
N
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
SUBWFB
SUBWFB REG, 0, 0
SUBWFB
0x19
0x0D
0x01
0x0C
0x0D
0x01
0x00
0x00
0x1B
0x1A
0x00
0x1B
0x00
0x01
0x01
0x00
0x03
0x0E
0x01
0xF5
0x0E
0x00
0x00
0x01
 2003 Microchip Technology Inc.
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