Default code question

[Andy L]

I was going through the default code today and I had passed this particular segment and wondered exactly how it works. to let you all know I am a new programmer and our current programmer is a senior and doesn't explain anything to me.

 p1_x = 255 - p1_y;
  p1_y = 255 - pwm05;

  pwm13 = pwm14 = Limit_Mix(2000 + p1_y + p1_x - 127);
  pwm15 = pwm16 = Limit_Mix(2000 + p1_y - p1_x + 127);

unsigned char Limit_Mix (int intermediate_value)
{
  static int limited_value;
  
  if (intermediate_value < 2000)
  {
    limited_value = 2000;
  }
  else if (intermediate_value > 2254)
  {
    limited_value = 2254;
  }
  else
  {
    limited_value = intermediate_value;
  }
  return (unsigned char) (limited_value - 2000);
}

I honestly have no clue on how that does a one joystick drive