assembler directive

An assembler directive is a message to the assembler that tells the assembler something it needs to know in order to carry out the assembly process; for example, an assemble directive tess the assembler where a program is to be located in memory.
<label> EQU <value> Equate
ORG <value> Origin
<label> DC <value> Define constant
<label> DS <value> Define storage
END <value> End of assembly language
In each case, the term <label> indicates a user-defined label (i.e., symbolic name) that must start in column 1 of the program, and <value> indicates a value that must be supplied by the programmer (this may be a number, or a symbolic name that has a value).
1.)Equate:-The EQU assembler directive simply equates a symbolic name to a numeric value.
2.)Origin:-The origin directive tells the assembler where to load instructions and data into memory.
3.)Define Constrant:-The define constant assembler directive allows you to put a data value in memory at the time that the program is first loaded.
4.)Define Storage:-The define storage directive is used to reserve one or more memory locations.
5.)END - END directive is placed after the last
statement of a program to tell the assembler that this is the end
of the program module. The assembler will ignore any
statement after an END directive.
6.)ENDP - End Procedure.
7.)ENDS - End Segment.
8.)GROUP - The GROUP directive is
used to group the logical segments.
9.)INCLUDE - This INCLUDE directive is
used to insert a block of source code from the named file
into the current source module.
10.)TYPE - TYPE operator instructs the assembler to
determine the type of a variable and determines the number of
bytes specified to that variable.
11.)PTR-used to assign a specific type of variable.
12.)EVEN-INSTRUCT to increment the location of the counter to the next even address.