5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  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 __tan = tan
  31 
  32 /* INDENT OFF */
  33 /*
  34  * tan(x)
  35  * Table look-up algorithm by K.C. Ng, November, 1989.
  36  *
  37  * kernel function:
  38  *      __k_tan         ... tangent function on [-pi/4,pi/4]
  39  *      __rem_pio2      ... argument reduction routine
  40  */
  41 /* INDENT ON */
  42 
  43 #include "libm.h"
  44 #include "libm_protos.h"
  45 #include <math.h>
  46 
  47 double
  48 tan(double x) {

  49         double y[2], z = 0.0;
  50         int n, ix;
  51 
  52         /* high word of x */
  53         ix = ((int *) &x)[HIWORD];
  54 
  55         /* |x| ~< pi/4 */
  56         ix &= 0x7fffffff;
  57         if (ix <= 0x3fe921fb)
  58                 return (__k_tan(x, z, 0));
  59 



  60         /* tan(Inf or NaN) is NaN */
  61         else if (ix >= 0x7ff00000) {
  62 #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
  63                 return (ix >= 0x7ff80000 ? x : x - x);       /* NaN */
  64                 /* assumes sparc-like QNaN */
  65 #else
  66                 return (x - x);                         /* NaN */
  67 #endif
  68         }
  69 
  70         /* argument reduction needed */
  71         else {
  72                 n = __rem_pio2(x, y);
  73                 return (__k_tan(y[0], y[1], n & 1));
  74         }
  75 }

   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  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 /*
  27  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 
  31 #pragma weak __tan = tan
  32 
  33 
  34 /*
  35  * tan(x)
  36  * Table look-up algorithm by K.C. Ng, November, 1989.
  37  *
  38  * kernel function:
  39  *      __k_tan         ... tangent function on [-pi/4,pi/4]
  40  *      __rem_pio2      ... argument reduction routine
  41  */

  42 
  43 #include "libm.h"
  44 #include "libm_protos.h"
  45 #include <math.h>
  46 
  47 double
  48 tan(double x)
  49 {
  50         double y[2], z = 0.0;
  51         int n, ix;
  52 
  53         /* high word of x */
  54         ix = ((int *)&x)[HIWORD];
  55 
  56         /* |x| ~< pi/4 */
  57         ix &= 0x7fffffff;


  58 
  59         if (ix <= 0x3fe921fb) {
  60                 return (__k_tan(x, z, 0));
  61         }
  62         /* tan(Inf or NaN) is NaN */
  63         else if (ix >= 0x7ff00000) {
  64 #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
  65                 return (ix >= 0x7ff80000 ? x : x - x);       /* NaN */
  66                 /* assumes sparc-like QNaN */
  67 #else
  68                 return (x - x);                         /* NaN */
  69 #endif
  70         }

  71         /* argument reduction needed */
  72         else {
  73                 n = __rem_pio2(x, y);
  74                 return (__k_tan(y[0], y[1], n & 1));
  75         }
  76 }