RS2_MASK
(MASK_SD | RS2_MASK | RS1_MASK)))
(MASK_SD | RS2_MASK | RS1_MASK))) {
#define rs2_index ((instr & RS2_MASK) >> RS2_SHIFT)
rs2 = (insn & RS2_MASK) >> RS2_SHIFT;
rs2 = (insn & RS2_MASK) >> RS2_SHIFT;