Datasheet

PIC18F6520/8520/6620/8620/6720/8720
DS39609C-page 288  2003-2013 Microchip Technology Inc.
POP Pop Top of Return Stack
Syntax: [ label ] POP
Operands: None
Operation: (TOS)  bit bucket
Status Affected: None
Encoding:
0000 0000 0000 0110
Description: The TOS value is pulled off the
return stack and is discarded. The
TOS value then becomes the
previous value that was pushed
onto the return stack.
This instruction is provided to
enable the user to properly manage
the return stack to incorporate a
software stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
POP TOS
value
No
operation
Example:
POP
GOTO NEW
Before Instruction
TOS = 0031A2h
Stack (1 level down) = 014332h
After Instruction
TOS = 014332h
PC = NEW
PUSH Push Top of Return Stack
Syntax: [ label ] PUSH
Operands: None
Operation: (PC+2)  TOS
Status Affected: None
Encoding:
0000 0000 0000 0101
Description: The PC+2 is pushed onto the top of
the return stack. The previous TOS
value is pushed down on the stack.
This instruction allows
implementing a software stack by
modifying TOS and then pushing it
onto the return stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode PUSH PC+2
onto return
stack
No
operation
No
operation
Example:
PUSH
Before Instruction
TOS = 00345Ah
PC = 000124h
After Instruction
PC = 000126h
TOS = 000126h
Stack (1 level down) = 00345Ah