1*25c28e83SPiotr Jasiukajtis /* 2*25c28e83SPiotr Jasiukajtis * CDDL HEADER START 3*25c28e83SPiotr Jasiukajtis * 4*25c28e83SPiotr Jasiukajtis * The contents of this file are subject to the terms of the 5*25c28e83SPiotr Jasiukajtis * Common Development and Distribution License (the "License"). 6*25c28e83SPiotr Jasiukajtis * You may not use this file except in compliance with the License. 7*25c28e83SPiotr Jasiukajtis * 8*25c28e83SPiotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9*25c28e83SPiotr Jasiukajtis * or http://www.opensolaris.org/os/licensing. 10*25c28e83SPiotr Jasiukajtis * See the License for the specific language governing permissions 11*25c28e83SPiotr Jasiukajtis * and limitations under the License. 12*25c28e83SPiotr Jasiukajtis * 13*25c28e83SPiotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each 14*25c28e83SPiotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15*25c28e83SPiotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the 16*25c28e83SPiotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying 17*25c28e83SPiotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner] 18*25c28e83SPiotr Jasiukajtis * 19*25c28e83SPiotr Jasiukajtis * CDDL HEADER END 20*25c28e83SPiotr Jasiukajtis */ 21*25c28e83SPiotr Jasiukajtis 22*25c28e83SPiotr Jasiukajtis /* 23*25c28e83SPiotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24*25c28e83SPiotr Jasiukajtis */ 25*25c28e83SPiotr Jasiukajtis /* 26*25c28e83SPiotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27*25c28e83SPiotr Jasiukajtis * Use is subject to license terms. 28*25c28e83SPiotr Jasiukajtis */ 29*25c28e83SPiotr Jasiukajtis 30*25c28e83SPiotr Jasiukajtis #include "libm.h" 31*25c28e83SPiotr Jasiukajtis 32*25c28e83SPiotr Jasiukajtis /* INDENT OFF */ 33*25c28e83SPiotr Jasiukajtis /* 34*25c28e83SPiotr Jasiukajtis * float __k_cos(double x); 35*25c28e83SPiotr Jasiukajtis * kernel (float) cos function on [-pi/4, pi/4], pi/4 ~ 0.785398164 36*25c28e83SPiotr Jasiukajtis * Input x is in double and assumed to be bounded by ~pi/4 in magnitude. 37*25c28e83SPiotr Jasiukajtis * 38*25c28e83SPiotr Jasiukajtis * Method: Let z = x * x, then 39*25c28e83SPiotr Jasiukajtis * C(x) = (C0 + C1*z + C2*z*z) * (C3 + C4*z + z*z) 40*25c28e83SPiotr Jasiukajtis * where 41*25c28e83SPiotr Jasiukajtis * C0 = 1.09349482127188401868272000389539985058873853699e-0003 42*25c28e83SPiotr Jasiukajtis * C1 = -5.03324285989964979398034700054920226866107675091e-0004 43*25c28e83SPiotr Jasiukajtis * C2 = 2.43792880266971107750418061559602239831538067410e-0005 44*25c28e83SPiotr Jasiukajtis * C3 = 9.14499072605666582228127405245558035523741471271e+0002 45*25c28e83SPiotr Jasiukajtis * C4 = -3.63151270591815439197122504991683846785293207730e+0001 46*25c28e83SPiotr Jasiukajtis * 47*25c28e83SPiotr Jasiukajtis * The remez error is bound by |cos(x) - C(x)| < 2**(-34.2) 48*25c28e83SPiotr Jasiukajtis * 49*25c28e83SPiotr Jasiukajtis * Constants: 50*25c28e83SPiotr Jasiukajtis * The hexadecimal values are the intended ones for the following constants. 51*25c28e83SPiotr Jasiukajtis * The decimal values may be used, provided that the compiler will convert 52*25c28e83SPiotr Jasiukajtis * from decimal to binary accurately enough to produce the hexadecimal values 53*25c28e83SPiotr Jasiukajtis * shown. 54*25c28e83SPiotr Jasiukajtis */ 55*25c28e83SPiotr Jasiukajtis /* INDENT ON */ 56*25c28e83SPiotr Jasiukajtis 57*25c28e83SPiotr Jasiukajtis static const double q[] = { 58*25c28e83SPiotr Jasiukajtis /* C0 = */ 1.09349482127188401868272000389539985058873853699e-0003, 59*25c28e83SPiotr Jasiukajtis /* C1 = */ -5.03324285989964979398034700054920226866107675091e-0004, 60*25c28e83SPiotr Jasiukajtis /* C2 = */ 2.43792880266971107750418061559602239831538067410e-0005, 61*25c28e83SPiotr Jasiukajtis /* C3 = */ 9.14499072605666582228127405245558035523741471271e+0002, 62*25c28e83SPiotr Jasiukajtis /* C4 = */ -3.63151270591815439197122504991683846785293207730e+0001, 63*25c28e83SPiotr Jasiukajtis }; 64*25c28e83SPiotr Jasiukajtis 65*25c28e83SPiotr Jasiukajtis #define C0 q[0] 66*25c28e83SPiotr Jasiukajtis #define C1 q[1] 67*25c28e83SPiotr Jasiukajtis #define C2 q[2] 68*25c28e83SPiotr Jasiukajtis #define C3 q[3] 69*25c28e83SPiotr Jasiukajtis #define C4 q[4] 70*25c28e83SPiotr Jasiukajtis 71*25c28e83SPiotr Jasiukajtis float 72*25c28e83SPiotr Jasiukajtis __k_cosf(double x) { 73*25c28e83SPiotr Jasiukajtis float ft; 74*25c28e83SPiotr Jasiukajtis double z; 75*25c28e83SPiotr Jasiukajtis int hx; 76*25c28e83SPiotr Jasiukajtis 77*25c28e83SPiotr Jasiukajtis hx = ((int *) &x)[HIWORD]; /* hx = leading x */ 78*25c28e83SPiotr Jasiukajtis if ((hx & ~0x80000000) < 0x3f100000) { /* |x| < 2**-14 */ 79*25c28e83SPiotr Jasiukajtis ft = (float) 1; 80*25c28e83SPiotr Jasiukajtis if (((int) x) == 0) /* raise inexact if x != 0 */ 81*25c28e83SPiotr Jasiukajtis return (ft); 82*25c28e83SPiotr Jasiukajtis } 83*25c28e83SPiotr Jasiukajtis z = x * x; 84*25c28e83SPiotr Jasiukajtis ft = (float) (((C0 + z * C1) + (z * z) * C2) * (C3 + z * (C4 + z))); 85*25c28e83SPiotr Jasiukajtis return (ft); 86*25c28e83SPiotr Jasiukajtis } 87