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 coshl = __coshl
  31 
  32 #include "libm.h"
  33 #include "longdouble.h"
  34 
  35 /*
  36  * COSH(X)
  37  * RETURN THE HYPERBOLIC COSINE OF X
  38  *
  39  * Method :
  40  *      1. Replace x by |x| (COSH(x) = COSH(-x)).
  41  *      2.
  42  *                                                      [ EXP(x) - 1 ]^2
  43  *          0        <= x <= 0.3465  :  COSH(x) := 1 + -------------------
  44  *                                                         2*EXP(x)
  45  *
  46  *                                                 EXP(x) +  1/EXP(x)
  47  *          0.3465   <= x <= thresh  :  COSH(x) := -------------------
  48  *                                                         2
  49  *          thresh   <= x <= lnovft  :  COSH(x) := EXP(x)/2
  50  *          lnovft   <= x <  INF     :  COSH(x) := SCALBN(EXP(x-MEP1*ln2),ME)

  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 __coshl = coshl
  31 
  32 #include "libm.h"
  33 #include "longdouble.h"
  34 
  35 /*
  36  * COSH(X)
  37  * RETURN THE HYPERBOLIC COSINE OF X
  38  *
  39  * Method :
  40  *      1. Replace x by |x| (COSH(x) = COSH(-x)).
  41  *      2.
  42  *                                                      [ EXP(x) - 1 ]^2
  43  *          0        <= x <= 0.3465  :  COSH(x) := 1 + -------------------
  44  *                                                         2*EXP(x)
  45  *
  46  *                                                 EXP(x) +  1/EXP(x)
  47  *          0.3465   <= x <= thresh  :  COSH(x) := -------------------
  48  *                                                         2
  49  *          thresh   <= x <= lnovft  :  COSH(x) := EXP(x)/2
  50  *          lnovft   <= x <  INF     :  COSH(x) := SCALBN(EXP(x-MEP1*ln2),ME)