Omron CJ - INSTRUCTIONS REFERENCE MANUAL 07-2009 Reference Manual page 579

3. Instructions
FIFO(633)
Reads first (oldest) word of data that was stored in the stack, shifts the remaining data down one word,
and decrements the pointer by one.
Stack
Pointer to last
word in stack
Pointer
Pointer
LIFO(634)
Reads the last (most recent) word of data that was stored in the stack. Decrements the pointer by one
and reads the data at this address (the most recent data stored in the stack). The read data will not be
cleared.
Stack
Pointer
To learn the number of data words in a stack, use an SNUM instruction.
Example: Learning the number of items on a conveyor
To read (reference), change (refresh), insert, or delete a data word within the stack, use SREAD,
SWRIT, SINS, and SDEL commands, respectively.
Example: To track items moving on a conveyor, treat the stack words as the items and manage
additions, discharges, and changes of the items
542
to
Data region
Pointer
Reads the content of A, decrements the pointer
by 1, deletes A, and shifts remaining data down.
B
Pointer
Data region
A
A is the last word
stored in the stack.
Stack
to
Data region
Stack
B
A
Data region
Decrements the pointer by one
and reads content of A.
CS/CJ/NSJ Series Instructions Reference Manual (W474)