compilers/linux86-0.16.17/libc/msdos/sound.c

   1
   2 #include <bios.h>
   3
   4 static int port_val = -1;
   5
   6 sound(freq)
   7 unsigned freq;  /* freq is in hertz */
   8 {
   9    if(port_val == -1 )
  10       port_val = inp(0x61);
  11
  12    freq = 1193180L / freq;
  13
  14    outp(0x61, port_val|3);
  15    outp(0x43, 0xb6);
  16    outp(0x42, freq&0xFF);
  17    outp(0x42, (freq>>8)&0xFF);
  18 }
  19
  20 nosound()
  21 {
  22    if( port_val )
  23       outp(0x61, port_val);
  24    else
  25       outp(0x61, inp(0x61)&~3);
  26 }
  27