1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24 */ 25 /* 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27 * Use is subject to license terms. 28 */ 29 30 #include "libm.h" 31 32 /* INDENT OFF */ 33 /* 34 * float __k_sin(double x); 35 * kernel (float) sin function on [-pi/4, pi/4], pi/4 ~ 0.785398164 36 * Input x is in double and assumed to be bounded by ~pi/4 in magnitude. 37 * 38 * Method: Let z = x * x, then 39 * S(x) = x(S0 + S1*z)(S2 + S3*z + z*z) 40 * where 41 * S0 = 1.85735322054308378716204874632872525989806770558e-0003, 42 * S1 = -1.95035094218403635082921458859320791358115801259e-0004, 43 * S2 = 5.38400550766074785970952495168558701485841707252e+0002, 44 * S3 = -3.31975110777873728964197739157371509422022905947e+0001, 45 * 46 * The remez error is bound by |(sin(x) - S(x))/x| < 2**(-28.2) 47 * 48 * Constants: 49 * The hexadecimal values are the intended ones for the following constants. 50 * The decimal values may be used, provided that the compiler will convert 51 * from decimal to binary accurately enough to produce the hexadecimal values 52 * shown. 53 */ 54 /* INDENT ON */ 55 56 static const double q[] = { 57 /* S0 = */ 1.85735322054308378716204874632872525989806770558e-0003, 58 /* S1 = */ -1.95035094218403635082921458859320791358115801259e-0004, 59 /* S2 = */ 5.38400550766074785970952495168558701485841707252e+0002, 60 /* S3 = */ -3.31975110777873728964197739157371509422022905947e+0001, 61 }; 62 63 #define S0 q[0] 64 #define S1 q[1] 65 #define S2 q[2] 66 #define S3 q[3] 67 68 float 69 __k_sinf(double x) { 70 float ft; 71 double z; 72 int hx; 73 74 hx = ((int *) &x)[HIWORD]; /* hx = leading x */ 75 if ((hx & ~0x80000000) < 0x3f100000) { /* if |x| < 2**-14 */ 76 ft = (float) x; 77 if ((int) x == 0) /* raise inexact if x != 0 */ 78 return (ft); 79 } 80 z = x * x; 81 ft = (float) ((x * (S0 + z * S1)) * (S2 + z * (S3 + z))); 82 return (ft); 83 } 84