PIC18F24 MICROCHIP [Microchip Technology], PIC18F24 Datasheet - Page 303

• Manufacturer Part Number: PIC18F24
• Description: 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

DECFSZ
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example:
 2004 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
PC
CNT
If CNT
If CNT
Q1
Q1
Q1
PC =
PC =
=
=
=
register ‘f’
operation
operation
operation
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
decremented. 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 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
CONTINUE
Read
0010
No
No
No
Q2
Q2
Q2
f
Address (HERE)
CNT – 1
0;
Address (CONTINUE)
0;
Address (HERE + 2)
[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
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
decremented. 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:
HERE
ZERO
NZERO
Read
0100
No
No
No
Q2
Q2
Q2
f
[0,1]
[0,1]
PIC18FXX8
255
3 cycles if skip and followed
by a 2-word instruction.
=
=
=
=
=
dest,
DCFSNZ TEMP
:
:
11da
operation
operation
operation
Process
?
TEMP – 1,
0;
Address (ZERO)
0;
Address (NZERO)
0
Data
No
No
No
Q3
Q3
Q3
DS41159D-page 301
f [,d [,a]]
ffff
destination
operation
operation
operation
Write to
No
No
No
Q4
Q4
Q4
ffff