Datasheet

PIC16C505
DS40192D-page 44  1999-2012 Microchip Technology Inc.
COMF Complement f
Syntax: [
label ] COMF f,d
Operands: 0  f  31
d  [0,1]
Operation: (f
)  (dest)
Status Affected: Z
Encoding:
0010 01df ffff
Description: The contents of register 'f' are
complemented. If 'd' is 0, the result
is stored in the W register. If 'd' is
1, the result is stored back in regis-
ter 'f'.
Words: 1
Cycles: 1
Example:
COMF REG1,0
Before Instruction
REG1 = 0x13
After Instruction
REG1 = 0x13
W=0xEC
DECF Decrement f
Syntax: [
label ] DECF f,d
Operands: 0  f  31
d  [0,1]
Operation: (f) – 1  (dest)
Status Affected: Z
Encoding:
0000 11df ffff
Description: Decrement register 'f'. If 'd' is 0, the
result is stored in the W register. If
'd' is 1, the result is stored back in
register 'f'.
Words: 1
Cycles: 1
Example:
DECF CNT,
1
Before Instruction
CNT = 0x01
Z=0
After Instruction
CNT = 0x00
Z=1
DECFSZ Decrement f, Skip if 0
Syntax: [
label ] DECFSZ f,d
Operands: 0  f  31
d  [0,1]
Operation: (f) – 1  d; skip if result = 0
Status Affected: None
Encoding:
0010 11df ffff
Description: The contents of register 'f' are dec-
remented. If 'd' is 0, the result is
placed in the W register. If 'd' is 1,
the result is placed back in register
'f'.
If the result is 0, the next instruc-
tion, which is already fetched, is
discarded and a NOP is executed
instead making it a two cycle
instruction.
Words: 1
Cycles: 1(2)
Example:
HERE DECFSZ CNT, 1
GOTO LOOP
CONTINUE 


Before Instruction
PC = address (HERE)
After Instruction
CNT = CNT - 1;
if CNT = 0,
PC = address (CONTINUE);
if CNT  0,
PC = address (HERE+1)
GOTO Unconditional Branch
Syntax: [
label ] GOTO k
Operands: 0  k  511
Operation: k  PC<8:0>;
STATUS<6:5>  PC<10:9>
Status Affected: None
Encoding:
101k kkkk kkkk
Description: GOTO is an unconditional branch.
The 9-bit immediate value is
loaded into PC bits <8:0>. The
upper bits of PC are loaded from
STATUS<6:5>. GOTO is a two cycle
instruction.
Words: 1
Cycles: 2
Example:
GOTO THERE
After Instruction
PC = address (THERE)