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_tan(double x); 35 * kernel (float) tan 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 * Constants: 39 * The hexadecimal values are the intended ones for the following constants. 40 * The decimal values may be used, provided that the compiler will convert 41 * from decimal to binary accurately enough to produce the hexadecimal values 42 * shown. 43 */ 44 45 static const double q[] = { 46 /* one */ 1.0, 47 /* P0 */ 4.46066928428959230679140546271810308098793029785e-0003, 48 /* P1 */ 4.92165316309189027066395283327437937259674072266e+0000, 49 /* P2 */ -7.11410648161473480044492134766187518835067749023e-0001, 50 /* P3 */ 4.08549808374053391446523164631798863410949707031e+0000, 51 /* P4 */ 2.50411070398050927821032018982805311679840087891e+0000, 52 /* P5 */ 1.11492064560251158411574579076841473579406738281e+0001, 53 /* P6 */ -1.50565540968422650891511693771462887525558471680e+0000, 54 /* P7 */ -1.81484378878349295050043110677506774663925170898e+0000, 55 /* T0 */ 3.333335997532835641297409611782510896641e-0001, 56 /* T1 */ 2.999997598248363761541668282006867229939e+00, 57 }; 58 /* INDENT ON */ 59 60 #define one q[0] 61 #define P0 q[1] 62 #define P1 q[2] 63 #define P2 q[3] 64 #define P3 q[4] 65 #define P4 q[5] 66 #define P5 q[6] 67 #define P6 q[7] 68 #define P7 q[8] 69 #define T0 q[9] 70 #define T1 q[10] 71 72 float 73 __k_tanf(double x, int n) { 74 float ft = 0.0; 75 double z, w; 76 int ix; 77 78 ix = ((int *) &x)[HIWORD] & ~0x80000000; /* ix = leading |x| */ 79 /* small argument */ 80 if (ix < 0x3f800000) { /* if |x| < 0.0078125 = 2**-7 */ 81 if (ix < 0x3f100000) { /* if |x| < 2**-14 */ 82 if ((int) x == 0) { /* raise inexact if x != 0 */ 83 ft = n == 0 ? (float) x : (float) (-one / x); 84 } 85 return (ft); 86 } 87 z = (x * T0) * (T1 + x * x); 88 ft = n == 0 ? (float) z : (float) (-one / z); 89 return (ft); 90 } 91 z = x * x; 92 w = ((P0 * x) * (P1 + z * (P2 + z)) * (P3 + z * (P4 + z))) 93 * (P5 + z * (P6 + z * (P7 + z))); 94 ft = n == 0 ? (float) w : (float) (-one / w); 95 return (ft); 96 } 97