/***************************************************************************/
/* Name : Sqrt.C                                                           */
/* Uses : Fast integer square root function                                */
/* Date : 4/24/2002                                                        */
/* Authors :                                                               */
/*   Stephen Bye - Orignal square root code posted on "comp.lang.c"        */
/*   Andrew Que <Que@StaAck.com>                                           */
/*                                                                         */
/* Unit revisions :                                                        */
/*   1.00 - 4/24/2002 - QUE - Creation                                     */
/*                                                                         */
/*                               Andrew Que                                */
/*                              Public Domain                              */
/***************************************************************************/
#include "Genral.H"

//--------------------------------------------------------------------------
// Returns integer square root value of input
// Orignal code: Stephen Bye
//--------------------------------------------------------------------------
uint16 SquareRoot( uint32 Number )
{
   #define Precision  ( 32 >> 1 ) 

   uint16 Root;
   uint16 RootSquared;
   uint32 Mask;
   uint32 MaskSquared;
   uint32 Test;
   uint16 Power;

   Root        = 0;
   RootSquared = 0;
   Mask        = 1  <<   ( Precision - 1 );
   MaskSquared = 1L << ( ( Precision - 1 ) << 1 );

   for ( Power = Precision; Power > 0; --Power )
   {
      Test = RootSquared + MaskSquared + ( (uint32)Root << Power );

      if ( Test <= Number )
      {
        RootSquared = Test;
        Root |= Mask;
      }

      Mask >>= 1;
      MaskSquared >>= 2;

   }

   return Root;
}