ORG directive: It is used to specify starting address of the Program. A 16bit address follows ORG
ORG 0020H will start program from 0020H memory location.
END directive: It indicates end of the assembly language program
DB directive: he DB directive is the most widely used data directive in the assembler. It is used to define the 8-bit data. When DB is used to define data, the numbers can be in decimal, binary, hex, or ASCII formats.
EQU directive: This is used to define a constant without occupying a memory location. The EQU directive does not set aside storage for a data item but associates a constant value with a data label so that when the label appears in the program, itp constant value will be substituted for the label.