1 /* $NetBSD: s_cosl.c,v 1.3 2024/05/08 01:42:23 riastradh Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-2-Clause 5 * 6 * Copyright (c) 2007 Steven G. Kargl 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice unmodified, this list of conditions, and the following 14 * disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __RCSID("$NetBSD: s_cosl.c,v 1.3 2024/05/08 01:42:23 riastradh Exp $"); 33 34 /* 35 * Limited testing on pseudorandom numbers drawn within [-2e8:4e8] shows 36 * an accuracy of <= 0.7412 ULP. 37 */ 38 39 #include "namespace.h" 40 #include <float.h> 41 42 #ifdef __weak_alias 43 __weak_alias(cosl, _cosl) 44 #endif 45 46 47 #ifdef __FreeBSD__ 48 #include "fpmath.h" 49 #endif 50 51 #include "math.h" 52 #include "math_private.h" 53 54 #ifdef __HAVE_LONG_DOUBLE 55 56 #if LDBL_MANT_DIG == 64 57 #include "../ld80/e_rem_pio2l.h" 58 #include "../ld80/k_cosl.c" 59 static const union ieee_ext_u 60 pio4u = LD80C(0xc90fdaa22168c235, -00001, 7.85398163397448309628e-01L); 61 #define pio4 (pio4u.extu_ld) 62 #elif LDBL_MANT_DIG == 113 63 #include "../ld128/e_rem_pio2l.h" 64 #include "../ld128/k_cosl.c" 65 static long double pio4 = 7.85398163397448309615660845819875721e-1L; 66 #else 67 #error "Unsupported long double format" 68 #endif 69 70 long double 71 cosl(long double x) 72 { 73 union ieee_ext_u z; 74 int e0; 75 long double y[2]; 76 long double hi, lo; 77 78 z.extu_ld = x; 79 z.extu_sign = 0; 80 81 /* If x = +-0 or x is a subnormal number, then cos(x) = 1 */ 82 if (z.extu_exp == 0) 83 return (1.0); 84 85 /* If x = NaN or Inf, then cos(x) = NaN. */ 86 if (z.extu_exp == 32767) 87 return ((x - x) / (x - x)); 88 89 ENTERI(); 90 91 /* Optimize the case where x is already within range. */ 92 if (z.extu_ld < pio4) 93 RETURNI(__kernel_cosl(z.extu_ld, 0)); 94 95 e0 = __ieee754_rem_pio2l(x, y); 96 hi = y[0]; 97 lo = y[1]; 98 99 switch (e0 & 3) { 100 case 0: 101 hi = __kernel_cosl(hi, lo); 102 break; 103 case 1: 104 hi = - __kernel_sinl(hi, lo, 1); 105 break; 106 case 2: 107 hi = - __kernel_cosl(hi, lo); 108 break; 109 case 3: 110 hi = __kernel_sinl(hi, lo, 1); 111 break; 112 } 113 114 RETURNI(hi); 115 } 116 #else 117 118 long double 119 cosl(long double x) 120 { 121 return cos(x); 122 } 123 124 #endif 125