Last In First Out: Lifo(634) - Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual

Table Data Processing Instructions
Examples
TB
Last word Stack
in stack
pointer
Stack
pointer
Last word
in stack

3-17-4 LAST IN FIRST OUT: LIFO(634)

Purpose
Ladder Symbol
Variations
Applicable Program Areas
712
When CIO 000000 is ON in the following example, FIFO(633) reads the con-
tent of D00004 (TB+4 for the stack beginning at D00000) and writes that data
to D00300.
TB:
PC memory address
of last word in stack
Stack pointer
After the data is written to D00300, the stack pointer is decremented by one
and the remaining data is shifted down. (The content of D00005 is shifted to
D00004 and the content of D00006 is shifted to D00005.)
PC memory address
of last word in stack
Stack pointer
–1
Reads the last word of data written to the specified stack (the newest data in
the stack).
LIFO(634)
TB
D
Variations Executed Each Cycle for ON Condition
Executed Once for Upward Differentiation
Executed Once for Downward Differentiation Not supported.
Immediate Refreshing Specification
Block program areas
OK
Read by FIFO(633).
D: D00300
D: D00300
TB: First stack address
D: Destination word
Step program areas
OK OK
Section 3-17
LIFO(634)
@LIFO(634)
Not supported.
Subroutines Interrupt tasks
OK