1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   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 __sinl = sinl
  32 
  33 /* BEGIN CSTYLED */
  34 /*
  35  * sinl(x)
  36  * Table look-up algorithm by K.C. Ng, November, 1989.
  37  *
  38  * kernel function:
  39  *      __k_sinl                ... sin function on [-pi/4,pi/4]
  40  *      __k_cosl                ... cos function on [-pi/4,pi/4]
  41  *      __rem_pio2l     ... argument reduction routine
  42  *
  43  * Method.
  44  *      Let S and C denote the sin and cos respectively on [-PI/4, +PI/4].
  45  *      1. Assume the argument x is reduced to y1+y2 = x-k*pi/2 in
  46  *         [-pi/2 , +pi/2], and let n = k mod 4.
  47  *      2. Let S=S(y1+y2), C=C(y1+y2). Depending on n, we have
  48  *
  49  *          n        sin(x)      cos(x)        tan(x)
  50  *     ----------------------------------------------------------
  51  *          0          S           C             S/C
  52  *          1          C          -S            -C/S
  53  *          2         -S          -C             S/C
  54  *          3         -C           S            -C/S
  55  *     ----------------------------------------------------------
  56  *
  57  * Special cases:
  58  *      Let trig be any of sin, cos, or tan.
  59  *      trig(+-INF)  is NaN, with signals;
  60  *      trig(NaN)    is that NaN;
  61  *
  62  * Accuracy:
  63  *      computer TRIG(x) returns trig(x) nearly rounded.
  64  */
  65 /* END CSTYLED */
  66 
  67 #include "libm.h"
  68 #include "longdouble.h"
  69 
  70 #include <sys/isa_defs.h>
  71 
  72 long double
  73 sinl(long double x)
  74 {
  75         long double y[2], z = 0.0L;
  76         int n, ix;
  77 
  78 #if defined(__i386) || defined(__amd64)
  79         int *px = (int *)&x;
  80 #endif
  81 
  82         /* sin(Inf or NaN) is NaN */
  83         if (!finitel(x))
  84                 return (x - x);
  85 
  86         /* High word of x. */
  87 #if defined(__i386) || defined(__amd64)
  88         XTOI(px, ix);
  89 #else
  90         ix = *(int *)&x;
  91 #endif
  92         /* |x| ~< pi/4 */
  93         ix &= 0x7fffffff;
  94 
  95         if (ix <= 0x3ffe9220) {
  96                 return (__k_sinl(x, z));
  97         }
  98         /* argument reduction needed */
  99         else {
 100                 n = __rem_pio2l(x, y);
 101 
 102                 switch (n & 3) {
 103                 case 0:
 104                         return (__k_sinl(y[0], y[1]));
 105                 case 1:
 106                         return (__k_cosl(y[0], y[1]));
 107                 case 2:
 108                         return (-__k_sinl(y[0], y[1]));
 109                 case 3:
 110                         return (-__k_cosl(y[0], y[1]));
 111                         /* NOTREACHED */
 112                 }
 113         }
 114 
 115         return (0.0L);
 116 }