PIC18F1220_07 Datasheet, PDF (212/308 Pages) Microchip Technology – 18/20/28-Pin High-Performance, Enhanced Flash Microcontrollers with 10-bit A/D and nanoWatt Technology

PIC18F1220/1320
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:
0000 0000 0000 0111
Description:
DAW adjusts the eight-bit value in
W, resulting from the earlier addi-
tion of two variables (each in
packed BCD format) and produces
a correct packed BCD result. The
Carry bit may be set by DAW regard-
less of its setting prior to the DAW
instruction.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Decode
Read
register W
Example 1:
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
DS39605F-page 210
© 2007 Microchip Technology Inc.