Servomotors practise, Servo Motor Control using AVR ATmega8

I had bought some chinese servomotors and decided to make a laser toy for my cat.

#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>

//TCCR0
#define CS0 0
#define CS1 1
#define CS2 2
#define TOIE0 0

// 4 MHz
int clock = 0;
int move_x = 20;
int move_y = 20;
int clock2 = 0;
int manual = -1;
int pressed = -1;
int x_increase = 0, y_increase = 0;

ISR(TIMER0_OVF_vect) // Interrupt when timer TNC0 is full
{

 clock++; // not great way to compute time
 if (clock == move_y) // every 1 - 2 ms pin is cleared
 {
  PORTC = PORTC ^ 0b00010000; // PD4
 }
 if (clock == move_x) // i got values through trial and error min 14 max 32
 {
  PORTC = PORTC ^ 0b00100000; // PD5
 }

 if(clock >= 251) // every 20 ms send impulse
 {
  PORTC = 0b00110000;
  clock = 0;
  clock2++;
 }

 if( manual == -1 && clock == 0 ) // If NOT user controlled
 {
  if(clock2 == 100) // about every 2 seconds
  {
   move_x = 26;
   move_y = 17;
  }
  else if(clock2 == 200) // move motors
  {
   move_x = 30;
   move_y = 20;
  }
  else if(clock2 == 300)
  {
   move_x = 20;
   move_y = 22;
  }
  else if(clock2 == 400)
  {
   move_x = 25;
   move_y = 21;
  }
  else if(clock2 >= 500)
  {
   move_x = 32;
   move_y = 19;
   clock2 = 0;
  }
 }

 if( manual == 1 && clock == 0 ) // If user controlled
 {
  if(clock2 >= 7) // Every 1/4 s move motor if button is pressed
  {
   if(x_increase == 1) move_x++;
   if(x_increase == -1) move_x--;

   if(y_increase == 1) move_y++;
   if(y_increase == -1) move_y--;

   x_increase = 0;
   y_increase = 0;
   clock2 = 0;
  }
 }

 if ((PIND & (1 << 0)) == 0 && pressed == -1)  // if utton is pressed
 {
  _delay_ms(50); // Switch debounce
  if ((PIND & (1 << 0)) == 0 && pressed == -1)
  {
   manual = -manual; // change control type
   pressed = 1; // check if pressed
  }
 }
 if ((PIND & (1 << 0)) == 1  && pressed == 1) // don't change controls 100 times
 {
  _delay_ms(50);
  if ((PIND & (1 << 0)) == 1 && pressed == 1) // move motors
  {
   pressed = -1; // 1 press
  }
 }
 if ((PIND & (1 << 1)) == 0 && move_x < 32 )  // other buttons
 {
  x_increase = 1;
 }
 if ((PIND & (1 << 2)) == 0 && move_x > 16) // for controlling motors
 {
  x_increase = -1;
 }
 if ((PIND & (1 << 3)) == 0 && move_y < 32)
 {
  y_increase = 1;
 }
 if ((PIND & (1 << 4)) == 0 && move_y > 16)
 {
  y_increase = -1;
 }
}


int main()
{
 DDRC=0xFF; // output
 DDRD=0x00; // input

 PORTD=0b00011111; // pull up on buttons
    // TIMER0
 TCCR0|=(0<<CS2)|(0<<CS1)|(1<<CS0);   // no frequency divider
 TIMSK|=(1<<TOIE0);   // interrupt on overflow of TNC0

 sei(); // allow interrupts

 while(1);
}