PIC16C71X
BCF
Bit Clear f
BTFSC
Bit Test, Skip if Clear
Syntax:
Operands:
[label] BCF f,b
Syntax:
[label] BTFSC f,b
0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operands:
0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operation:
Status Affected:
Encoding:
0 → (f<b>)
Operation:
skip if (f<b>) = 0
None
None
Status Affected:
Encoding:
01
00bb
bfff
ffff
01
10bb
bfff
ffff
If bit 'b' in register 'f' is '1' then the next
instruction is executed.
If bit 'b', in register 'f', is '0' then the next
instruction is discarded, and a NOP is
executed instead, making this a 2TCY
instruction.
Description:
Words:
Bit 'b' in register 'f' is cleared.
Description:
1
1
Cycles:
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register
'f'
Process
data
Write
register 'f'
Words:
1
Cycles:
1(2)
Q Cycle Activity:
Q1
Q2
Q3
Q4
BCF
FLAG_REG, 7
Example
Decode
Read
register 'f'
Process
data
NOP
Before Instruction
FLAG_REG = 0xC7
If Skip:
(2nd Cycle)
Q1
After Instruction
FLAG_REG = 0x47
Q2
Q3
Q4
NOP
NOP
NOP
NOP
HERE
FALSE
TRUE
BTFSC FLAG,1
Example
GOTO
PROCESS_CODE
•
•
•
Before Instruction
PC
=
address HERE
After Instruction
if FLAG<1> = 0,
PC =
if FLAG<1>=1,
address TRUE
BSF
Bit Set f
Syntax:
Operands:
[label] BSF f,b
PC =
address FALSE
0 ≤ f ≤ 127
0 ≤ b ≤ 7
Operation:
Status Affected:
Encoding:
1 → (f<b>)
None
01
01bb
bfff
ffff
Bit 'b' in register 'f' is set.
Description:
Words:
1
1
Cycles:
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register
'f'
Process
data
Write
register 'f'
BSF
FLAG_REG,
7
Example
Before Instruction
FLAG_REG = 0x0A
After Instruction
FLAG_REG = 0x8A
DS30272A-page 72
1997 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
