5.26 SET
Set a symbol equal to an expression.
The SET directive assigns a value to a label. This label can then be used in later expressions. Unlike the EQU directive, a label assigned to a value by the SET directive can be changed (redefined) later in the program.
.SET label = expression
.SET FOO = 0x114; set FOO to point to an SRAM location lds r0, FOO; load location into r0 .SET FOO = FOO + 1 ; increment (redefine) FOO. This would be illegal if using .EQU lds r1, FOO ; load next location into r1