PIC18FXX8 Datasheet, PDF (296/402 Pages) Microchip Technology – 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module

PIC18FXX8
BTFSC
Bit Test File, Skip if Clear
Syntax:
[ label ] BTFSC f,b[,a]
Operands:
0 ≤ f ≤ 255
0≤b≤7
a ∈ [0,1]
Operation:
skip if (f<b>) = 0
Status Affected: None
Encoding:
1011 bbba ffff ffff
Description:
If bit ‘b’ in register ‘f’ is ‘0’, then the next
instruction is skipped.
If bit ‘b’ is ‘0’, then the next instruction
fetched during the current instruction
execution is discarded and a NOP is
executed instead, making this 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).
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
register ‘f’
Process
Data
If skip:
Q1
Q2
Q3
No
operation
No
operation
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
Q4
No
operation
Q4
No
operation
No
operation
Example:
HERE
FALSE
TRUE
Before Instruction
PC
=
After Instruction
If FLAG<1> =
PC
=
If FLAG<1> =
PC
=
BTFSC
:
:
FLAG, 1
address (HERE)
0;
address (TRUE)
1;
address (FALSE)
BTFSS
Bit Test File, Skip if Set
Syntax:
[ label ] BTFSS f,b[,a]
Operands:
0 ≤ f ≤ 255
0≤b≤7
a ∈ [0,1]
Operation:
skip if (f<b>) = 1
Status Affected: None
Encoding:
1010 bbba ffff ffff
Description:
If bit ‘b’ in register ‘f’ is ‘1’, then the next
instruction is skipped.
If bit ‘b’ is ‘1’, then the next instruction
fetched during the current instruction
execution is discarded and a NOP is
executed instead, making this 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).
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
register ‘f’
Process
Data
If skip:
Q1
Q2
Q3
No
operation
No
operation
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
Q4
No
operation
Q4
No
operation
No
operation
Example:
HERE
FALSE
TRUE
Before Instruction
PC
=
After Instruction
If FLAG<1> =
PC
=
If FLAG<1> =
PC
=
BTFSS
:
:
FLAG, 1
address (HERE)
0;
address (FALSE)
1;
address (TRUE)
DS41159D-page 294
 2004 Microchip Technology Inc.