Datasheet

 1996 Microchip Technology Inc. DS30430B-page 63
PIC16F8X
NOP No Operation
Syntax: [
label ] NOP
Operands: None
Operation: No operation
Status Affected: None
Encoding:
00 0000 0xx0 0000
Description:
No operation.
Words: 1
Cycles: 1
Example
NOP
OPTION Load Option Register
Syntax: [ label ] OPTION
Operands: None
Operation: (W) → OPTION
Status Affected: None
Encoding:
00 0000 0110 0010
Description:
The contents of the W register are
loaded in the OPTION register. This
instruction is supported for code com-
patibility with PIC16C5X products.
Since OPTION is a readable/writable
register, the user can directly address
it.
Words: 1
Cycles: 1
Example
Note: To maintain upward compatibility with
future PIC16FXX products, do not use
this instruction.
RETFIE Return from Interrupt
Syntax: [
label ] RETFIE
Operands: None
Operation: TOS → (PC),
1 → GIE
Status Affected: None
Encoding:
00 0000 0000 1001
Description:
The Stack is popped and Top of Stack
(TOS) is loaded into the PC. Interrupts
are enabled by setting the Global
Interrupt Enable bit. This is a two
cycle instruction.
Words: 1
Cycles: 2
Example
RETFIE
After Interrupt
PC = TOS
GIE = 1
RETLW Return Literal to W
Syntax: [
label ] RETLW k
Operands: 0 ≤ k ≤ 255
Operation: k → (W),
TOS → (PC)
Status Affected: None
Encoding:
11 01xx kkkk kkkk
Description:
The W register is loaded with the eight
bit literal 'k'. The program counter is
loaded from the top of the stack (the
return address). This is a two cycle
instruction.
Words: 1
Cycles: 2
Example
TABLE
CALL TABLE ;W contains table
;offset value
• ;W now has table value
•
•
ADDWF PC ;W = offset
RETLW k1 ;Begin table
RETLW k2 ;
•
•
•
RETLW kn ;End of table
Before Instruction
W = 0x07
After Instruction
W = value of k7