PIC18F2331/2431/4331/4431
POP
Pop Top of Return Stack
PUSH
Push Top of Return Stack
Syntax:
[ label ] POP
None
Syntax:
[ label ] PUSH
None
Operands:
Operation:
Status Affected:
Encoding:
Description:
Operands:
Operation:
Status Affected:
Encoding:
Description:
(TOS) bit bucket
None
(PC + 2) TOS
None
0000
0000
0000
0110
0000
0000
0000
0101
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.
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 to implement a
software stack by modifying TOS, and
then push it onto the return stack.
Words:
Cycles:
1
1
Words:
Cycles:
1
1
Q Cycle Activity:
Q1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q2
Q3
Q4
Decode
PUSH
No
No
Decode
No
operation
POP TOS
value
No
operation
PC + 2 onto
return stack
operation
operation
Example:
POP
Example:
PUSH
GOTO
NEW
Before Instruction
Before Instruction
TOS
Stack (1 level down)
TOS
PC
=
=
0x00345A
0x000124
=
=
0x0031A2
0x014332
After Instruction
After Instruction
PC
TOS
=
=
=
0x000126
0x000126
0x00345A
TOS
PC
=
=
0x014332
NEW
Stack (1 level down)
DS39616D-page 312
2010 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
