1 /* $NetBSD: s_cosl.c,v 1.1 2024/01/21 18:53:18 christos 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 1.1 2024/01/21 18:53:18 christos 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 #ifdef __i386__ 42 #include <ieeefp.h> 43 #endif 44 45 #ifdef __weak_alias 46 __weak_alias(cosl, _cosl) 47 #endif 48 49 50 #ifdef __FreeBSD__ 51 #include "fpmath.h" 52 #endif 53 54 #include "math.h" 55 #include "math_private.h" 56 57 #ifdef __HAVE_LONG_DOUBLE 58 59 #if LDBL_MANT_DIG == 64 60 #include "../ld80/e_rem_pio2l.h" 61 #include "../ld80/k_cosl.c" 62 static const union ieee_ext_u 63 pio4u = LD80C(0xc90fdaa22168c235, -00001, 7.85398163397448309628e-01L); 64 #define pio4 (pio4u.extu_ld) 65 #elif LDBL_MANT_DIG == 113 66 #include "../ld128/e_rem_pio2l.h" 67 #include "../ld128/k_cosl.c" 68 long double pio4 = 7.85398163397448309615660845819875721e-1L; 69 #else 70 #error "Unsupported long double format" 71 #endif 72 73 long double 74 cosl(long double x) 75 { 76 union ieee_ext_u z; 77 int e0; 78 long double y[2]; 79 long double hi, lo; 80 81 z.extu_ld = x; 82 z.extu_sign = 0; 83 84 /* If x = +-0 or x is a subnormal number, then cos(x) = 1 */ 85 if (z.extu_exp == 0) 86 return (1.0); 87 88 /* If x = NaN or Inf, then cos(x) = NaN. */ 89 if (z.extu_exp == 32767) 90 return ((x - x) / (x - x)); 91 92 ENTERI(); 93 94 /* Optimize the case where x is already within range. */ 95 if (z.extu_ld < pio4) 96 RETURNI(__kernel_cosl(z.extu_ld, 0)); 97 98 e0 = __ieee754_rem_pio2l(x, y); 99 hi = y[0]; 100 lo = y[1]; 101 102 switch (e0 & 3) { 103 case 0: 104 hi = __kernel_cosl(hi, lo); 105 break; 106 case 1: 107 hi = - __kernel_sinl(hi, lo, 1); 108 break; 109 case 2: 110 hi = - __kernel_cosl(hi, lo); 111 break; 112 case 3: 113 hi = __kernel_sinl(hi, lo, 1); 114 break; 115 } 116 117 RETURNI(hi); 118 } 119 #else 120 121 long double 122 cosl(long double x) 123 { 124 return cos(x); 125 } 126 127 #endif 128