/* --- bit --- 
 
   turn bits on and off and like

   (c) 5.5.1995 Mika V„liviita

   freeware, use as you wish at your own risk


   my bbbs is

   evaluate!
   +358-30-5455104  V32B

*/

/*

 Something you should be aware of:
 =================================

 say we have a number...

 decimal:
 85

 hex:
 55
 
 binary:
 01010101 <- the rightmost number is counted as bit 0 not 1!
 ^
 the leftmost number is counted here as bit 7

 let's have an example:

 01010101 (= 85)
       ^
       this is bit 1
 
 now we turn bit 1 ON, and here is the result:

 01010111 (= 87)

 and if you use above functions for it, do it like this:

 printf("85 and 2^1 = %u",biton(1,85));

 easy!

*/


// implementation of fex 2^5
// couldn't find it in scipt.gui
// so did it myself.
// no values checked
function pow($bas,$pow) {

  var $foo,$bar;
  $bar=$bas;

  switch($pow) {    
    case 0: { $foo=1; break; }
    case 1: { $foo=$bas; break; }
    default: {
      for ($foo=0; $foo < $pow-1; $foo=$foo+1) {
        $bar=$bar*$bas;
      }
      $foo=$bar;
      break;
    }
  }
  // printf(" þ%uþ ",$foo);
  return($foo);
}


// turn bit $bit ON in number $in
function biton($bit,$in) {
  return($in | pow(2,$bit));
}


// turn bit $bit OFF in number $in
function bitoff($bit,$in) {
  return($in & (-pow(2,$bit)-1));
}


// toggle bit $bit in number $in
function bittgl($bit,$in) {
  return($in ^ pow(2,$bit));
}


function main() {
  printf("\n");
  printf("\e[0;1m Demonstration of functionality:\e[0m\n");
  printf("\n");
  printf(" biton(4,11) = %u\n",biton(4,11));
  printf(" biton(1,11) = %u\n",biton(1,11));
  printf("\n");
  printf(" bitoff(1,11) = %u\n",bitoff(1,11));
  printf(" bitoff(2,11) = %u\n",bitoff(2,11));
  printf("\n");
  printf(" bittgl(2,11) = %u\n",bittgl(2,11));
  printf(" bittgl(1,11) = %u\n",bittgl(1,11));
  printf("\n");
  printf(" pow(2,16) = %u\n",pow(2,16));
  printf(" pow(5,6) = %u\n",pow(5,6));
  printf("\n");
}