Sound frequency For CSS Compiler

#include <16F877.h>
#device adc=8
#FUSES NOWDT ,XT                                        
#use delay(clock=4000000)

void sound (char freq,int16 time)  // Sound Generate
  {
    unsigned char i;
    while (time>0)
       {
        output_low (pin_b0);                      
        for (i=1;i<=freq;i++)
            time--;
        output_high (pin_b0);                    
        for (i=1;i<=freq;i++)
            time--;
      }
 }

void main(){
   set_tris_a(0xff);   
   set_tris_b(0x00);
   setup_adc_ports(NO_ANALOGS);
   setup_adc(ADC_OFF);
   output_b(0x00);
 while(true){
   if(!input(pin_a0)){    
     sound(50,1000);
     sound(60,5000);
     sound(10,6000);     
     sound(100,40000); }
   else{
     sound(0,0);
    }
  }
}