+* THE DATA LAYOUT OF THE STACK DATA IS AS FOLLOWING:
+*
+* SIZE OCT '1000 SIZE OF THE STACK IN MACHINE WORDS
+* PTR DAC ** THE STACK POINTER
+* FILL DAC ** THE FILL COUNTER
+* OVER DAC OFL OPTIONAL POINTER TO OVERFLOW ERROR ROUTINE
+* UNDR DAC UFL OPTIONAL POINTER TO UNDERFLOW ERROR ROUTINE
+* STCK BSS '1000 THE STACK DATA
+*
+* IF CUSTOM ERROR HANDLING ROUTINES ARE NOT TO BE USED, SET THE TWO
+* POINTER LOCATIONS TO ZERO. THEN, INTERNAL ERROR ROUTINES WILL BE
+* USED. SIZE AND THE FUNCTION POINTERS HAVE TO BE INITIALISED. THE
+* OTHER LOCATIONS ARE INITIALISED BY THE STACK ROUTINES.