THE 8051 MICROCONTROLLER: THE PROGRAMMER’S PERSPECTIVE 497
ORG ORG is a directive which means ‘origin’. In the context of assembly language
programming, it defi nes the starting address for any item (data or code) in the pro-
gram memory (ROM). We have already used the statement ORG 0 in Examples 13.1
and 13.2.
EQU is directive allows us to equate names to constants. e assembler just replaces
the names by the values mentioned.
Examples
COST EQU 34 ;equate the label COST to 34
PRICE EQU 56H ;equate the label PRICE by 56H
DB is directive stands for ‘data byte’ and places an 8-bit number constant at this
memory (ROM) location. If labels are used for these memory locations, a ‘colon’ should
suffi x the labels.
Examples
NUMBER: DB 67H ;store ...