学步园

void sound(unsigned int freq);
main()
{
unsigned int freq;
do
{
do
{
freq=rand();
}while(freq>1000);
sound(freq);
}while(!kbhit());
}
void sound(unsigned int freq)
{
unsigned i;
union
{
long divisor;
unsigned char c[2];
}count;
unsigned char bits;
count.divisor=119328/freq;
outportb(0x43,0xb6);
outportb(0x42,count.c[0]);
outportb(0x42,count.c[1]);
bits=inportb(0x61);
outportb(0x61,bits|3);
for(i=0;i<20000;i++);
outportb(0x61,bits&0xfc);
}