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Annotation of OSKit-Mach/oskit/pc/osenv_bell.c, revision 1.1.1.1

1.1       root        1: /* Support for minimal console's bell using PC speaker.
                      2:    This replaces the default oskit function that busy-waits.  */
                      3: 
                      4: #include <oskit/machine/pc/direct_cons.h>
                      5: #include <oskit/machine/pc/speaker.h>
                      6: 
                      7: #include "time_out.h"
                      8: 
                      9: #define BELL_FREQUENCY 750     /* Hz */
                     10: #define        BELL_DURATION   (hz>>3) /* 1/8th second duration */
                     11: 
                     12: /* This is the private timer used to turn off the speaker.  */
                     13: static timer_elt_data_t bell_timer = { fcn: (int (*)()) &pc_speaker_off };
                     14: 
                     15: void
                     16: direct_cons_bell (void)
                     17: {
                     18:   /* Cancel the timeout for a bell we are already ringing.  */
                     19:   if (reset_timeout (&bell_timer))
                     20:     /* Turn the speaker off for an instant to distinguish this bell
                     21:        from the next.  */
                     22:     pc_speaker_off ();
                     23: 
                     24:   /* Turn the speaker on and set the timeout to turn it off.  */
                     25:   pc_speaker_on (BELL_FREQUENCY);
                     26:   set_timeout (&bell_timer, BELL_DURATION);
                     27: }

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