1176358Sdas/* From: @(#)k_cos.c 1.3 95/01/18 */ 2176358Sdas/* 3176358Sdas * ==================================================== 4176358Sdas * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5176358Sdas * Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans. 6176358Sdas * 7176358Sdas * Developed at SunSoft, a Sun Microsystems, Inc. business. 8176358Sdas * Permission to use, copy, modify, and distribute this 9176358Sdas * software is freely granted, provided that this notice 10176358Sdas * is preserved. 11176358Sdas * ==================================================== 12176358Sdas */ 13176358Sdas 14176358Sdas#include <sys/cdefs.h> 15176358Sdas__FBSDID("$FreeBSD$"); 16176358Sdas 17176358Sdas/* 18176358Sdas * ld128 version of k_cos.c. See ../src/k_cos.c for most comments. 19176358Sdas */ 20176358Sdas 21176358Sdas#include "math_private.h" 22176358Sdas 23176358Sdas/* 24176358Sdas * Domain [-0.7854, 0.7854], range ~[-1.80e-37, 1.79e-37]: 25176358Sdas * |cos(x) - c(x))| < 2**-122.0 26176358Sdas * 27176358Sdas * 113-bit precision requires more care than 64-bit precision, since 28176358Sdas * simple methods give a minimax polynomial with coefficient for x^2 29176358Sdas * that is 1 ulp below 0.5, but we want it to be precisely 0.5. See 30176358Sdas * ../ld80/k_cosl.c for more details. 31176358Sdas */ 32176358Sdasstatic const double 33176358Sdasone = 1.0; 34176358Sdas 35176358Sdasstatic const long double 36176358SdasC1 = 0.04166666666666666666666666666666658424671L, 37176358SdasC2 = -0.001388888888888888888888888888863490893732L, 38176358SdasC3 = 0.00002480158730158730158730158600795304914210L, 39176358SdasC4 = -0.2755731922398589065255474947078934284324e-6L, 40176358SdasC5 = 0.2087675698786809897659225313136400793948e-8L, 41176358SdasC6 = -0.1147074559772972315817149986812031204775e-10L, 42176358SdasC7 = 0.4779477332386808976875457937252120293400e-13L; 43176358Sdas 44176358Sdasstatic const double 45176358SdasC8 = -0.1561920696721507929516718307820958119868e-15, 46176358SdasC9 = 0.4110317413744594971475941557607804508039e-18, 47176358SdasC10 = -0.8896592467191938803288521958313920156409e-21, 48176358SdasC11 = 0.1601061435794535138244346256065192782581e-23; 49176358Sdas 50176358Sdaslong double 51176358Sdas__kernel_cosl(long double x, long double y) 52176358Sdas{ 53176358Sdas long double hz,z,r,w; 54176358Sdas 55176358Sdas z = x*x; 56176358Sdas r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*(C6+z*(C7+ 57176358Sdas z*(C8+z*(C9+z*(C10+z*C11)))))))))); 58176358Sdas hz = 0.5*z; 59176358Sdas w = one-hz; 60176358Sdas return w + (((one-w)-hz) + (z*r-x*y)); 61176358Sdas} 62