PIC18F2221 MICROCHIP [Microchip Technology], PIC18F2221 Datasheet - Page 295

• Manufacturer Part Number: PIC18F2221
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

DECFSZ
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example:
© 2007 Microchip Technology Inc.
Q Cycle Activity:
If skip:
If skip and followed by 2-word instruction:
Before Instruction
After Instruction
operation
operation
operation
Decode
PC
CNT
If CNT
If CNT
Q1
Q1
No
No
No
Q1
PC =
PC =
=
=
=
≠
register ‘f’
operation
operation
operation
Decrement f, Skip if 0
DECFSZ f {,d {,a}}
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
(f) – 1 → dest,
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 is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 24.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
1
1(2)
Note: 3 cycles if skip and followed
HERE
CONTINUE
Read
0010
Q2
No
Q2
No
No
Q2
Address (HERE)
CNT – 1
0;
Address (CONTINUE)
0;
Address (HERE + 2)
by a 2-word instruction.
11da
DECFSZ
GOTO
operation
operation
operation
Process
Data
Q3
No
Q3
No
No
Q3
ffff
CNT, 1, 1
LOOP
destination
operation
operation
operation
Write to
Q4
Q4
No
Q4
No
No
ffff
Preliminary
DCFSNZ
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example:
Q Cycle Activity:
If skip:
If skip and followed by 2-word instruction:
PIC18F4321 FAMILY
Before Instruction
After Instruction
operation
operation
operation
Decode
TEMP
TEMP
If TEMP
If TEMP
Q1
Q1
No
Q1
No
No
PC
PC
register ‘f’
operation
operation
operation
Decrement f, Skip if Not 0
DCFSNZ
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
(f) – 1 → dest,
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 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 is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 24.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
1
1(2)
Note:
HERE
ZERO
NZERO
Read
0100
Q2
Q2
Q2
No
No
No
3 cycles if skip and followed
by a 2-word instruction.
=
=
=
=
≠
=
DCFSNZ
:
:
f {,d {,a}}
11da
operation
operation
operation
?
TEMP – 1,
0;
Address (ZERO)
0;
Address (NZERO)
Process
Data
Q3
Q3
No
Q3
No
No
DS39689E-page 293
ffff
TEMP, 1, 0
destination
operation
operation
operation
Write to
Q4
Q4
Q4
No
No
No
ffff