set_tval_irq
set_tval_irq(timer, xval, ctl);
set_tval_irq(timer, -1, CTL_ENABLE | CTL_IMASK);
set_tval_irq(timer, -1, CTL_ENABLE | CTL_IMASK);
set_tval_irq(timer, 0, CTL_ENABLE);
set_tval_irq(timer, msec_to_cycles(delta_1_ms), CTL_ENABLE);