PIC18F4550-IP Datasheet, PDF (333/438 Pages) Microchip Technology – 28/40/44-Pin, High-Performance, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2455/2550/4455/4550
CPFSGT
Compare f with W, Skip if f > W
Syntax:
CPFSGT f {,a}
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
(f) – (W),
skip if (f) > (W)
(unsigned comparison)
Status Affected:
None
Encoding:
0110 010a ffff ffff
Description:
Compares the contents of data memory
location ‘f’ to the contents of the W by
performing an unsigned subtraction.
If the contents of ‘f’ are greater than the
contents of WREG, then the fetched
instruction is discarded and a NOP is
executed instead, making this 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 26.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Decode
Read
Process
register ‘f’
Data
If skip:
Q1
Q2
Q3
No
No
No
operation operation operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
No
No
No
operation operation operation
No
No
No
operation operation operation
Q4
No
operation
Q4
No
operation
Q4
No
operation
No
operation
Example:
HERE
CPFSGT REG, 0
NGREATER :
GREATER :
Before Instruction
PC
=
W
=
After Instruction
If REG
>
PC
=
If REG
≤
PC
=
Address (HERE)
?
W;
Address (GREATER)
W;
Address (NGREATER)
CPFSLT
Compare f with W, Skip if f < W
Syntax:
CPFSLT f {,a}
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
(f) – (W),
skip if (f) < (W)
(unsigned comparison)
Status Affected:
None
Encoding:
0110 000a ffff ffff
Description:
Compares the contents of data memory
location ‘f’ to the contents of W by
performing an unsigned subtraction.
If the contents of ‘f’ are less than the
contents of W, then the fetched
instruction is discarded and a NOP is
executed instead, making this 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).
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Decode
Q2
Read
register ‘f’
Q3
Process
Data
Q4
No
operation
If skip:
Q1
No
operation
Q2
No
operation
Q3
No
operation
Q4
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Q4
No
operation
No
operation
Example:
HERE
NLESS
LESS
CPFSLT REG, 1
:
:
Before Instruction
PC
=
W
=
After Instruction
If REG
<
PC
=
If REG
≥
PC
=
Address (HERE)
?
W;
Address (LESS)
W;
Address (NLESS)
© 2009 Microchip Technology Inc.
DS39632E-page 331