static FT_Int ft_trig_prenorm ( FT_Vector * vec ) [static]

Definition at line 100 of file fttrigon.c.

Referenced by FT_Atan2(), FT_Vector_Length(), FT_Vector_Polarize(), and FT_Vector_Rotate().

  {
    FT_Fixed  x, y, z;
    FT_Int    shift;


    x = vec->x;
    y = vec->y;

    z     = ( ( x >= 0 ) ? x : - x ) | ( (y >= 0) ? y : -y );
    shift = 0;

#if 1
    /* determine msb bit index in `shift' */
    if ( z >= ( 1L << 16 ) )
    {
      z     >>= 16;
      shift  += 16;
    }
    if ( z >= ( 1L << 8 ) )
    {
      z     >>= 8;
      shift  += 8;
    }
    if ( z >= ( 1L << 4 ) )
    {
      z     >>= 4;
      shift  += 4;
    }
    if ( z >= ( 1L << 2 ) )
    {
      z     >>= 2;
      shift  += 2;
    }
    if ( z >= ( 1L << 1 ) )
    {
      z    >>= 1;
      shift += 1;
    }

    if ( shift <= 27 )
    {
      shift  = 27 - shift;
      vec->x = x << shift;
      vec->y = y << shift;
    }
    else
    {
      shift -= 27;
      vec->x = x >> shift;
      vec->y = y >> shift;
      shift  = -shift;
    }

#else /* 0 */

    if ( z < ( 1L << 27 ) )
    {
      do
      {
        shift++;
        z <<= 1;
      } while ( z < ( 1L << 27 ) );
      vec->x = x << shift;
      vec->y = y << shift;
    }
    else if ( z > ( 1L << 28 ) )
    {
      do
      {
        shift++;
        z >>= 1;
      } while ( z > ( 1L << 28 ) );

      vec->x = x >> shift;
      vec->y = y >> shift;
      shift  = -shift;
    }

#endif /* 0 */

    return shift;
  }

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