1176360Sdas/*- 2176360Sdas * Copyright (c) 2007 Steven G. Kargl 3176360Sdas * All rights reserved. 4176360Sdas * 5176360Sdas * Redistribution and use in source and binary forms, with or without 6176360Sdas * modification, are permitted provided that the following conditions 7176360Sdas * are met: 8176360Sdas * 1. Redistributions of source code must retain the above copyright 9176360Sdas * notice unmodified, this list of conditions, and the following 10176360Sdas * disclaimer. 11176360Sdas * 2. Redistributions in binary form must reproduce the above copyright 12176360Sdas * notice, this list of conditions and the following disclaimer in the 13176360Sdas * documentation and/or other materials provided with the distribution. 14176360Sdas * 15176360Sdas * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16176360Sdas * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17176360Sdas * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18176360Sdas * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19176360Sdas * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20176360Sdas * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21176360Sdas * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22176360Sdas * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23176360Sdas * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24176360Sdas * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25176360Sdas */ 26176360Sdas 27176360Sdas#include <sys/cdefs.h> 28176360Sdas__FBSDID("$FreeBSD$"); 29176360Sdas 30176360Sdas/* 31176360Sdas * Limited testing on pseudorandom numbers drawn within [-2e8:4e8] shows 32176360Sdas * an accuracy of <= 0.7412 ULP. 33176360Sdas */ 34176360Sdas 35176360Sdas#include <float.h> 36240828Skargl#ifdef __i386__ 37240828Skargl#include <ieeefp.h> 38240828Skargl#endif 39176360Sdas 40176360Sdas#include "math.h" 41176360Sdas#include "math_private.h" 42176360Sdas#if LDBL_MANT_DIG == 64 43221234Skargl#include "../ld80/e_rem_pio2l.h" 44176360Sdas#elif LDBL_MANT_DIG == 113 45221234Skargl#include "../ld128/e_rem_pio2l.h" 46176360Sdas#else 47176360Sdas#error "Unsupported long double format" 48176360Sdas#endif 49176360Sdas 50176360Sdaslong double 51176360Sdascosl(long double x) 52176360Sdas{ 53176360Sdas union IEEEl2bits z; 54221234Skargl int e0; 55221234Skargl long double y[2]; 56176360Sdas long double hi, lo; 57176360Sdas 58176360Sdas z.e = x; 59176360Sdas z.bits.sign = 0; 60176360Sdas 61176360Sdas /* If x = +-0 or x is a subnormal number, then cos(x) = 1 */ 62176360Sdas if (z.bits.exp == 0) 63176360Sdas return (1.0); 64176360Sdas 65176360Sdas /* If x = NaN or Inf, then cos(x) = NaN. */ 66176360Sdas if (z.bits.exp == 32767) 67176360Sdas return ((x - x) / (x - x)); 68176360Sdas 69240828Skargl ENTERI(); 70240828Skargl 71176360Sdas /* Optimize the case where x is already within range. */ 72176360Sdas if (z.e < M_PI_4) 73240828Skargl RETURNI(__kernel_cosl(z.e, 0)); 74176360Sdas 75221234Skargl e0 = __ieee754_rem_pio2l(x, y); 76221234Skargl hi = y[0]; 77221234Skargl lo = y[1]; 78176360Sdas 79176360Sdas switch (e0 & 3) { 80176360Sdas case 0: 81176360Sdas hi = __kernel_cosl(hi, lo); 82176360Sdas break; 83176360Sdas case 1: 84176360Sdas hi = - __kernel_sinl(hi, lo, 1); 85176360Sdas break; 86176360Sdas case 2: 87176360Sdas hi = - __kernel_cosl(hi, lo); 88176360Sdas break; 89176360Sdas case 3: 90176360Sdas hi = __kernel_sinl(hi, lo, 1); 91176360Sdas break; 92176360Sdas } 93176360Sdas 94240828Skargl RETURNI(hi); 95176360Sdas} 96