AND / ANDI

and  rd, rs1, rs2
andi rd, rs1, imm12

Compute a bitwise AND. ANDI sign-extends its 12-bit immediate before applying it.

andi a0, a0, 0xff      # retain the low byte
and  a0, a0, a1        # mask using a register

x86 connection: equivalent bit operation to and, without flags and with a separate destination.