PIC18F242 MICROCHIP [Microchip Technology], PIC18F242 Datasheet - Page 233

• Manufacturer Part Number: PIC18F242
• Description: 28/40-pin High Performance, Enhanced FLASH Microcontrollers with 10-Bit A/D
• Manufacturer: MICROCHIP [Microchip Technology]

DECFSZ
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example:
© 2006 Microchip Technology Inc.
Q Cycle Activity:
If skip:
If skip and followed by 2-word instruction:
Before Instruction
After Instruction
operation
operation
operation
Decode
No
No
No
Q1
Q1
PC
CNT
If CNT
If CNT
Q1
PC =
PC =
=
=
=
operation
operation
operation
register 'f'
Decrement f, skip if 0
[ label ] DECFSZ f [,d [,a]]
0
d
a
(f) – 1
skip if result = 0
None
The contents of register 'f' are dec-
remented. If 'd' is 0, the result is
placed in W. If 'd' is 1, the result is
placed back in register 'f' (default).
If the result is 0, the next instruc-
tion, which is already fetched, is
discarded, and a NOP is executed
instead, making it a two-cycle
instruction. 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).
1
1(2)
Note: 3 cycles if skip and followed
HERE
CONTINUE
Read
No
No
No
0010
Q2
Q2
Q2
Address (HERE)
CNT - 1
0;
Address (CONTINUE)
0;
Address (HERE+2)
f
[0,1]
[0,1]
255
by a 2-word instruction.
dest,
11da
operation
operation
operation
GOTO
DECFSZ
Process
Data
No
No
No
Q3
Q3
Q3
ffff
CNT, 1, 1
LOOP
destination
operation
operation
operation
Write to
No
No
No
Q4
Q4
Q4
ffff
DCFSNZ
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example:
Q Cycle Activity:
If skip:
If skip and followed by 2-word instruction:
Before Instruction
After Instruction
operation
operation
operation
Decode
No
No
No
TEMP
TEMP
If TEMP
If TEMP
Q1
Q1
Q1
PC
PC
register 'f'
operation
operation
operation
Decrement f, skip if not 0
[ label ] DCFSNZ
0
d
a
(f) – 1
skip if result
None
The contents of register 'f' are dec-
remented. If 'd' is 0, the result is
placed in W. If 'd' is 1, the result is
placed back in register 'f' (default).
If the result is not 0, the next
instruction, which is already
fetched, is discarded, and a NOP is
executed instead, making it a two-
cycle instruction. 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).
1
1(2)
Note: 3 cycles if skip and followed
HERE
ZERO
NZERO
Read
0100
No
No
No
Q2
Q2
Q2
f
[0,1]
[0,1]
PIC18FXX2
255
by a 2-word instruction.
=
=
=
=
=
dest,
DCFSNZ
:
:
11da
operation
operation
operation
?
TEMP - 1,
0;
Address (ZERO)
0;
Address (NZERO)
Process
Data
0
No
No
No
Q3
Q3
Q3
DS39564C-page 231
ffff
TEMP, 1, 0
f [,d [,a]
destination
operation
operation
operation
Write to
No
No
No
Q4
Q4
Q4
ffff