expression1[expression2]
The index operator indicates addition with a scale factor. It is similar to the addition operator. expression1 can be any expression which has array type. expression2 must be a constant expression. The assembler multiplies expression2 by the size of the array element type and adds it to expression1.
ARR DV LONG[4] ; an array of four 32-bit values W3 EQU ARR[3] ; set W4 to the address ARR + 3*(SIZE LONG) ; which is ARR+12