4.9.16 Equ Directive

The EQU pseudo-op defines a symbol and equates its value to an expression. For example:

thomas EQU 123h

The identifier thomas will be given the value 123h. EQU is legal only when the symbol has not previously been defined. See 4.9.51 Set Directive for redefinition of values.

This directive does not reserve memory for the symbol specified. Use the DS directive to reserve data memory (see 4.9.13 Ds Directive). An EQU performs a similar function to the preprocessor’s #define directive (see 5.1 Preprocessor Directives).

Since EQU directives do not contribute to the output, they are processed separately to other instructions and directives. Thus, the program location counter cannot be used in EQU operand expressions.