Using a PIC16F877A and ASM in MPLAB 8.92

What is the purpose of getting the # in W before the CALL of a table (short or long) to display a text message on a LCD module? What is in the W after the CALL a data table when display a text message on the LCD?

Example:

How to gain access of the data in a SHORT table? Short Table: Access a table content with PCL modification only MSG :Messaqe data table