PIC18F2331 Datasheet, PDF (308/396 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High Performance PWM and A/D

PIC18F2331/2431/4331/4431
DAW
Syntax:
Operands:
Operation:
Decimal Adjust W Register
[ label ] DAW
None
If [W<3:0> >9] or [DC = 1] then
(W<3:0>) + 6 → W<3:0>;
else
(W<3:0>) → W<3:0>;
If [W<7:4> >9] or [C = 1] then
(W<7:4>) + 6 → W<7:4>;
else
(W<7:4>) → W<7:4>;
Status Affected: C, DC
Encoding:
Description:
0000 0000 0000 0111
DAW adjusts the eight-bit value in
W, resulting from the earlier
addition of two variables (each in
packed BCD format) and produces
a correct packed BCD result. The
carry bit may be set by DAW
regardless of its setting prior to the
DAW instruction.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Decode
Read
register W
Example1:
DAW
Q3
Process
Data
Q4
Write
W
Before Instruction
W
= 0xA5
C
=0
DC
=0
After Instruction
W
= 0x05
C
=1
DC
=0
Example 2:
Before Instruction
W
= 0xCE
C
=0
DC
=0
After Instruction
W
= 0x34
C
=1
DC
=0
DECF
Decrement f
Syntax:
[ label ] DECF f [,d [,a]]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) – 1 → dest
Status Affected: C, DC, N, OV, Z
Encoding:
0000 01da ffff ffff
Description:
Decrement register ‘f’. 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’ = 1, then the
bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
DECF CNT,
Before Instruction
CNT
Z
= 0x01
=0
After Instruction
CNT
Z
= 0x00
=1
DS39616B-page 306
Preliminary
 2003 Microchip Technology Inc.