Chiptune Noisemaker revised

/* 
 * File:   noisegenmain.c
 * Author: Hans Mikelson
 *
 * Created on February 13, 2015, 2:42 PM
 * Revised February 22, 2015
 * This program creates a random sequence of various types of noises
 * ranging from computer game like noises to white like noise.
 * These are all based on random or periodic on off pulses from the
 * microcontroller.  This program uses the 12f683 microcontroller but
 * should be adaptable to other brands of microcontroller.
 */

#if defined(__XC)
    #include <xc.h>         /* XC8 General Include File */
#elif defined(HI_TECH_C)
    #include <htc.h>        /* HiTech General Include File */
#endif

#include <stdint.h>        /* For uint8_t definition */
#include <stdbool.h>       /* For true/false definition */
#include <stdlib.h>     /*rand()*/

#pragma config MCLRE=OFF,CP=OFF,WDTE=OFF,FOSC=INTOSCIO
#define _XTAL_FREQ 4000000
uint8_t sGPIO;

void init()
{
    //Configure GPIO Port
    ANSEL =  0b00000000;  //Configure all GPIO pins as digital
    TRISIO = 0b11000100;  //Set GP1-5 as outputs and the rest as inputs
    OPTION_REGbits.nGPPU = 0;
    WPU = 0b00000100;     //Enable weak pullups on GP2
    //Configuer AD Convertor
    ADCON0 = 0x00;        //AD disabled
    ADRESH = 0x00;        //Init the AD Register
    //Configure Comparator
    CMCON0 = 0xFF;   // Comparator is turned off
    CMCON1 = 0x00;   // Comparator is turned off
    //Interrupt configuration
    INTCON = 0x00;   //Disable all interrupts
}

void vdelay(int n)
{
    int i;
    for (i=0;i<=n;i++)
    {
     __delay_us(1);
    }
}

void noise1(uint8_t r3) // PWM sweep high f to low f
{
 int i,j,r1,r2;
 r1=rand() & (r3-1);
 r2=r3/r1;
 for (j=0;j<r1;j++)
  {
   for (i=0;i<j;i++)
    {
     GPIO = 0b11110111;
     vdelay(i*r2);
     GPIO = 0b11000000;
     vdelay((j-i)*r2);
    }
   for (i=0;i<j;i++)
    {
     GPIO = 0b11110111;
     vdelay((j-i)*r2);
     GPIO = 0b11000000;
     vdelay(i*r2);
    }
  }
}

void noise4(uint8_t r3) // PWM sweep low f to high f
{
 int i,j,r1,r2;
 r1=rand() & (r3-1);
 r2=r3/r1;
 for (j=r1;j>0;j--)
  {
   for (i=0;i<r1-j;i++)
    {
     GPIO = 0b11110111;
     vdelay(i*r2);
     GPIO = 0b11000000;
     vdelay((j-i)*r2);
    }
   for (i=0;i<r1-j;i++)
    {
     GPIO = 0b11110111;
     vdelay((j-i)*r2);
     GPIO = 0b11000000;
     vdelay(i*r2);
    }
  }
}

void noise2(uint8_t r3) //PWM sweep down, laser
{
 int i,j,r1,r2;
 r1=rand() & (r3-1);
 r2=r3/r1;
 for (j=r2;j<r1;j++)
  {
   for (i=0;i<j;i++)
    {
     GPIO = 0b11110111;
     vdelay(r2);
     GPIO = 0b11000000;
     vdelay((j-i)*r2);
    }
  }
}

void noise3(uint8_t r3) // Pulse noise with different frequencies
{
 int j,r1,r2;
 r1=rand() & 2047;
 r2 = 32*r3/r1;
 for (j=0;j<r2;j++)
  {
   GPIO = 0b11110111;
   vdelay(rand() & (r3-1));
   GPIO = 0b11000000;
   vdelay(rand() & (r3-1));
  }
}

void noise5(uint8_t r3) // Long random clicks
{
 int j,r1;
 r1=rand() & (r3-1);
 for (j=0;j<r1/4;j++)
  {
   GPIO = 0b11110111;
   vdelay(r3*8);
   GPIO = 0b11000000;
   vdelay(rand());
  }
}

void noise6(uint8_t r3) // Short random clicks
{
 int j,r1;
 r1=rand() & (r3-1);
 for (j=0;j<r1/2;j++)
  {
   GPIO = 0b11110111;
   vdelay(r3*2);
   GPIO = 0b11000000;
   vdelay(rand() & 8191);
  }
}

void noise7(uint8_t r3) // PWM sweep low f to high f
{
 int i,j,r1,r2;
 r1=(rand() & (r3-1))/4;
 r2=r3/r1;
 for (j=r1;j>0;j--)
  {
   for (i=0;i<r1-j;i++)
    {
     GPIO = 0b11110111;
     vdelay(i*r2);
     GPIO = 0b11000000;
     vdelay((j-i)*r2);
     vdelay(rand() & ((r3-1)/4));
    }
   for (i=0;i<r1-j;i++)
    {
     GPIO = 0b11110111;
     vdelay((j-i)*r2);
     vdelay(rand() & ((r3-1)/4));
     GPIO = 0b11000000;
     vdelay(i*r2);
    }
  }
}

void main()
{
uint8_t ra[8]={2,4,4,8,16,32,64,128};
int r,r4;

 init();
 r=0;
 while(1)
  {
   //r = rand()&7;
   if (GPIObits.GP2 == 0)
    {
     r=(r+1)%7;
     vdelay(1000000);
    }
   r4=rand()&7;
   switch (r)
    {
     case 1:
     noise1(ra[r4]);
     //vdelay(rand());
     break;

     case 2:
     noise2(ra[r4]);
     //vdelay(rand());
     break;

     case 3:
     noise3(ra[r4]);
     //vdelay(rand());
     break;

     case 4:
     noise1(ra[r4]);
     noise4(ra[r4]);
     //vdelay(rand());
     break;

     case 5:
     noise5(ra[r4]);
     //vdelay(rand());
     break;

     case 6:
     noise6(ra[r4]);
     //vdelay(rand());
     break;

     default:
     noise7(ra[r4]);
     //vdelay(rand());
    }
  }
}