PIC18F2331 Datasheet, PDF (306/396 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High Performance PWM and A/D

PIC18F2331/2431/4331/4431
COMF
Complement f
Syntax:
[ label ] COMF f [,d [,a]]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
( f ) → dest
Status Affected: N, Z
Encoding:
0001 11da ffff ffff
Description:
The contents of register ‘f’ are com-
plemented. 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
Example:
Read
register ‘f’
COMF
Process
Data
REG, W
Write to
destination
Before Instruction
REG = 0x13
After Instruction
REG = 0x13
W
= 0xEC
CPFSEQ
Compare f with W, skip if f = W
Syntax:
[ label ] CPFSEQ f [,a]
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
(f) – (W),
skip if (f) = (W)
(unsigned comparison)
Status Affected: None
Encoding:
0110 001a ffff ffff
Description:
Compares the contents of data
memory location ‘f’ to the contents
of W by performing an unsigned
subtraction.
If ‘f’ = W, then the fetched instruc-
tion is discarded and a NOP is
executed instead, making this a
two-cycle instruction. If ‘a’ is 0, the
Access Bank will be selected, over-
riding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Decode
Read
register ‘f'’
If skip:
Q1
Q2
Q3
Process
Data
Q3
Q4
No
operation
Q4
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
No
operation
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NEQUAL
EQUAL
CPFSEQ REG
:
:
Before Instruction
PC Address =
W
=
REG
=
HERE
?
?
After Instruction
If REG
PC
If REG
PC
= W;
= Address (EQUAL)
≠ W;
= Address (NEQUAL)
DS39616B-page 304
Preliminary
 2003 Microchip Technology Inc.