Commit 6a51d83a authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

mc146818rtc: simplify check_update_timer 



Move all the optimized cases together, since they all have UF=1 in
common.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent da3a392f

hw/timer/mc146818rtc.c

+11 −13
Original line number Diff line number Diff line
@@ -291,26 +291,14 @@ static void check_update_timer(RTCState *s) 


    /* From the data sheet: "Holding the dividers in reset prevents

     * interrupts from operating, while setting the SET bit allows"

     * them to occur.  However, it will prevent an alarm interrupt

     * from occurring, because the time of day is not updated.

     * them to occur.

     */

    if ((s->cmos_data[RTC_REG_A] & 0x60) == 0x60) {

        timer_del(s->update_timer);

        return;

    }

    if ((s->cmos_data[RTC_REG_C] & REG_C_UF) &&

        (s->cmos_data[RTC_REG_B] & REG_B_SET)) {

        timer_del(s->update_timer);

        return;

    }

    if ((s->cmos_data[RTC_REG_C] & REG_C_UF) &&

        (s->cmos_data[RTC_REG_C] & REG_C_AF)) {

        timer_del(s->update_timer);

        return;

    }



    guest_nsec = get_guest_rtc_ns(s) % NANOSECONDS_PER_SECOND;

    /* if UF is clear, reprogram to next second */

    next_update_time = qemu_clock_get_ns(rtc_clock)

        + NANOSECONDS_PER_SECOND - guest_nsec;
@@ -321,7 +309,17 @@ static void check_update_timer(RTCState *s) 
    s->next_alarm_time = next_update_time +

                         (next_alarm_sec - 1) * NANOSECONDS_PER_SECOND;



    /* If UF is already set, we might be able to optimize. */

    if (s->cmos_data[RTC_REG_C] & REG_C_UF) {

        /* If AF cannot change (i.e. either it is set already, or

         * SET=1 and then the time is not updated), nothing to do.

         */

        if ((s->cmos_data[RTC_REG_B] & REG_B_SET) ||

            (s->cmos_data[RTC_REG_C] & REG_C_AF)) {

            timer_del(s->update_timer);

            return;

        }



        /* UF is set, but AF is clear.  Program the timer to target

         * the alarm time.  */

        next_update_time = s->next_alarm_time;