5.13 EQU

Set a symbol equal to an expression.

The EQU directive assigns a value to a label. This label can then be used in later expressions. A label assigned to a value by the EQU directive is a constant and can not be changed or redefined.

Syntax
.EQU label = expression
Example
.EQU io_offset = 0x23 
.EQU porta = io_offset + 2.CSEG ; Start code segment 
clr r2 ; Clear register 2 
out porta,r2 ; Write to Port A