bitfield_extract
reg_div = bitfield_extract(reg_val, div->u.s.shift, div->u.s.width);
reg_div = bitfield_extract(reg_val, div->u.s.shift,
parent_sel = bitfield_extract(reg_val, sel->shift, sel->width);
parent_sel = bitfield_extract(reg_val, sel->shift, sel->width);