kernel/sound/speaker.asm

   1 ;----------------------------------------------------------;
   2 ; BOS kernel                Christoffer Bubach, 2004-2005. ;
   3 ;----------------------------------------------------------;
   4 ;                                                          ;
   5 ;     Internal PCspeaker functions.                        ;
   6 ;                                                          ;
   7 ;----------------------------------------------------------;
   8
   9 ;-----------------------;
  10 ;  turn on PC speaker   ;
  11 ;    bx = frequency     ;
  12 ;-----------------------;
  13 speaker_on:
  14         mov    dx, 0x12
  15         mov    ax, 0x34DC
  16         div    bx
  17         mov    bl, al
  18         mov    al, 0xB6
  19         out    0x43, al
  20         mov    al, bl
  21         out    0x42, al
  22         mov    al, ah
  23         out    0x42, al
  24         in     al, 0x61
  25         or     al, 3
  26         out    0x61, al
  27         ret
  28
  29
  30 ;----------------------;
  31 ;  turn speaker off    ;
  32 ;----------------------;
  33 speaker_off:
  34         push   ax
  35         in     al, 0x61
  36         and    al, 0xFC                               ; some do 0xFD, some 0xFC... :/
  37         out    0x61, al
  38         pop    ax
  39         ret
  40
  41
  42 ;----------------------------------;
  43 ; PC-speaker; beep                 ;
  44 ;----------------------------------;
  45 beep:
  46         push   eax
  47         push   ecx
  48         in     al, 0x61                               ; turn the speaker on.
  49         or     al, 3
  50         out    0x61, al
  51         mov    ecx, 50
  52         call   delay                                  ; timer.inc
  53         call   speaker_off
  54         pop    ecx
  55         pop    eax
  56         ret