Hallo giri anto (giri@ikp.component.astra.co.id),

It seems like you are triying to access bits of B register. I can't see it as accessing array. You can use bit shifting to access those bits as array of bits. See Oleg's reply.

If you (insist) to implement arrays in assembly, try this:
1. make space in your memory segment to hold value of the array,
2. access the elements using pointer register such @R0, @R1 or @DPTR

You have to cunsult the manual of your assembler for point 1.

The "bible" chapter 2 describe the lists of mnemonics on using pointer register.

Selamat bekerja.