PIC18F6X2X Datasheet, PDF (308/386 Pages) Microchip Technology – 64/80-Pin High Performance, 64-Kbyte Enhanced FLASH Microcontrollers with A/D

PIC18F6X2X/8X2X
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 previ-
ous 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
Decode
No
operation
Q3
POP TOS
value
Q4
No
operation
Example:
POP
GOTO
Before Instruction
TOS
=
Stack (1 level down)=
NEW
0031A2h
014332h
After Instruction
TOS
PC
= 014332h
= 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 implement-
ing a software stack by modifying
TOS, and then pushing it onto the
return stack.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Decode
PUSH PC+2
onto return
stack
Q3
No
operation
Q4
No
operation
Example:
PUSH
Before Instruction
TOS
PC
= 00345Ah
= 000124h
After Instruction
PC
=
TOS
=
Stack (1 level down)=
000126h
000126h
00345Ah
DS39612A-page 306
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 2003 Microchip Technology Inc.