workloads/audio/test-audio.c

   1 #include "stdio.h"
   2
   3 #define RATE 11250
   4 #include "newgame-sound.c"
   5
   6 unsigned char *next_sample;
   7 unsigned char *stop_sound;
   8
   9 extern void interruptvector(void);
  10
  11 long time_at_last_run = 0;
  12 long delta = 0;
  13
  14
  15 void
  16 interrupthandler(long unsigned interrupt_source)
  17 {
  18         setInterval(FREQUENCY / 11250 - 100);
  19
  20         long time = now();
  21
  22         if (next_sample != stop_sound) {
  23                 DAC_both = *next_sample++ << 6;
  24         }
  25
  26         delta = time - time_at_last_run;
  27         time_at_last_run = time;
  28 }
  29
  30 int
  31 main()
  32 {
  33         fb_clear();
  34
  35         mmix_fprintf(1, "Hello?", 0);
  36
  37         next_sample = stop_sound = blob + sizeof blob;
  38
  39         /*
  40          * XXX 8 and even 7 distorts the sound. Why?  AAhh, it's only
  41          * when on head phones.  Amplified it sounds great
  42          */
  43         unsigned scale = 6;
  44         unsigned sw;
  45
  46         for (;;) {
  47                 unsigned char *p;
  48                 long unsigned my_sample, time_for_next;
  49
  50                 mmix_printf("Starting sound.  Scale is %d\n", scale);
  51
  52                 time_for_next = now() + (FREQUENCY / RATE);
  53                 for (p = blob; p != blob + sizeof blob; ++p) {
  54                         MMIX_IOSPACE[11] = (long) p >> 8;
  55                         my_sample = *p;
  56                         my_sample = my_sample << scale;
  57                         time_for_next += (FREQUENCY / RATE);
  58                         while (now() < time_for_next)
  59                                 ;
  60                         DAC_both = my_sample;
  61                 }
  62
  63                 while ((sw = get_switches()) == 0);
  64                 if (sw & (SW2|SW3))
  65                         scale += (sw & SW3) ? 1 : -1;
  66                 else if (sw & SW1)
  67                         stdout = !stdout;
  68                 else if (sw & SW0)
  69                         break;
  70         }
  71
  72         mmix_printf("Trying interrupts!\n", 0);
  73
  74         setInterruptVector(interruptvector);
  75         setIntrMask(1 << 7); // Enable interval
  76
  77         for (;;) {
  78                 mmix_printf("Starting sound\n", 0);
  79                 next_sample = blob;
  80
  81                 setInterval(FREQUENCY / RATE);
  82
  83                 while ((get_switches() & SW3) == 0)
  84                         mmix_printf("delta %d\n", delta);
  85                 while ((get_switches() & SW3) != 0);
  86         }
  87 }