10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 /*
  26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29 
  30 #if defined(ELFOBJ)
  31 #pragma weak hypot = __hypot
  32 #endif
  33 
  34 /* INDENT OFF */
  35 /*
  36  * Hypot(x, y)
  37  * by K.C. Ng for SUN 4.0 libm, updated 3/11/2003.
  38  * Method :
  39  * A. When rounding is rounded-to-nearest:
  40  *      If z = x * x + y * y has error less than sqrt(2) / 2 ulp than
  41  *      sqrt(z) has error less than 1 ulp.
  42  *      So, compute sqrt(x*x+y*y) with some care as follows:
  43  *      Assume x > y > 0;
  44  *      1. Check whether save and set rounding to round-to-nearest
  45  *      2. if x > 2y  use
  46  *              xh*xh+(y*y+((x-xh)*(x+xh))) for x*x+y*y
  47  *      where xh = x with lower 32 bits cleared;  else
  48  *      3. if x <= 2y use
  49  *              x2h*yh+((x-y)*(x-y)+(x2h*(y-yh)+(x2-x2h)*y))
  50  *      where x2 = 2*x, x2h = 2x with lower 32 bits cleared, yh = y with
  51  *      lower 32 bits chopped.
  52  *

  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 /*
  26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29 

  30 #pragma weak hypot = __hypot

  31 
  32 /* INDENT OFF */
  33 /*
  34  * Hypot(x, y)
  35  * by K.C. Ng for SUN 4.0 libm, updated 3/11/2003.
  36  * Method :
  37  * A. When rounding is rounded-to-nearest:
  38  *      If z = x * x + y * y has error less than sqrt(2) / 2 ulp than
  39  *      sqrt(z) has error less than 1 ulp.
  40  *      So, compute sqrt(x*x+y*y) with some care as follows:
  41  *      Assume x > y > 0;
  42  *      1. Check whether save and set rounding to round-to-nearest
  43  *      2. if x > 2y  use
  44  *              xh*xh+(y*y+((x-xh)*(x+xh))) for x*x+y*y
  45  *      where xh = x with lower 32 bits cleared;  else
  46  *      3. if x <= 2y use
  47  *              x2h*yh+((x-y)*(x-y)+(x2h*(y-yh)+(x2-x2h)*y))
  48  *      where x2 = 2*x, x2h = 2x with lower 32 bits cleared, yh = y with
  49  *      lower 32 bits chopped.
  50  *