CAUSEF_IV
clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1);
val = CAUSEF_IV;
set_c0_cause(CAUSEF_IV);
set_c0_cause(CAUSEF_IV);
change &= (CAUSEF_DC | CAUSEF_IV | CAUSEF_WP |
clear_c0_cause(CAUSEF_IV);
set_c0_cause(CAUSEF_IV);