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Diffstat (limited to 'usr/src/lib/libm/common/C/sincospi.c')
| -rw-r--r-- | usr/src/lib/libm/common/C/sincospi.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/C/sincospi.c b/usr/src/lib/libm/common/C/sincospi.c new file mode 100644 index 0000000000..66c3821dcc --- /dev/null +++ b/usr/src/lib/libm/common/C/sincospi.c @@ -0,0 +1,191 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ + +/* + * Copyright 2011 Nexenta Systems, Inc. All rights reserved. + */ +/* + * Copyright 2006 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma weak sincospi = __sincospi + +/* INDENT OFF */ +/* + * void sincospi(double x, double *s, double *c) + * *s = sin(pi*x); *c = cos(pi*x); + * + * Algorithm, 10/17/2002, K.C. Ng + * ------------------------------ + * Let y = |4x|, z = floor(y), and n = (int)(z mod 8.0) (displayed in binary). + * 1. If y == z, then x is a multiple of pi/4. Return the following values: + * --------------------------------------------------- + * n x mod 2 sin(x*pi) cos(x*pi) tan(x*pi) + * --------------------------------------------------- + * 000 0.00 +0 ___ +1 ___ +0 + * 001 0.25 +\/0.5 +\/0.5 +1 + * 010 0.50 +1 ___ +0 ___ +inf + * 011 0.75 +\/0.5 -\/0.5 -1 + * 100 1.00 -0 ___ -1 ___ +0 + * 101 1.25 -\/0.5 -\/0.5 +1 + * 110 1.50 -1 ___ -0 ___ +inf + * 111 1.75 -\/0.5 +\/0.5 -1 + * --------------------------------------------------- + * 2. Otherwise, + * --------------------------------------------------- + * n t sin(x*pi) cos(x*pi) tan(x*pi) + * --------------------------------------------------- + * 000 (y-z)/4 sinpi(t) cospi(t) tanpi(t) + * 001 (z+1-y)/4 cospi(t) sinpi(t) 1/tanpi(t) + * 010 (y-z)/4 cospi(t) -sinpi(t) -1/tanpi(t) + * 011 (z+1-y)/4 sinpi(t) -cospi(t) -tanpi(t) + * 100 (y-z)/4 -sinpi(t) -cospi(t) tanpi(t) + * 101 (z+1-y)/4 -cospi(t) -sinpi(t) 1/tanpi(t) + * 110 (y-z)/4 -cospi(t) sinpi(t) -1/tanpi(t) + * 111 (z+1-y)/4 -sinpi(t) cospi(t) -tanpi(t) + * --------------------------------------------------- + * + * NOTE. This program compute sinpi/cospi(t<0.25) by __k_sin/cos(pi*t, 0.0). + * This will return a result with error slightly more than one ulp (but less + * than 2 ulp). If one wants accurate result, one may break up pi*t in + * high (tpi_h) and low (tpi_l) parts and call __k_sin/cos(tip_h, tip_lo) + * instead. + */ + +#include "libm.h" +#include "libm_synonyms.h" +#include "libm_protos.h" +#include "libm_macros.h" +#include <math.h> +#if defined(__SUNPRO_C) +#include <sunmath.h> +#endif + +static const double + pi = 3.14159265358979323846, /* 400921FB,54442D18 */ + sqrth_h = 0.70710678118654757273731092936941422522068023681640625, + sqrth_l = -4.8336466567264565185935844299127932213411660131004e-17; +/* INDENT ON */ + +void +sincospi(double x, double *s, double *c) { + double y, z, t; + int n, ix, k; + int hx = ((int *) &x)[HIWORD]; + unsigned h, lx = ((unsigned *) &x)[LOWORD]; + + ix = hx & ~0x80000000; + n = (ix >> 20) - 0x3ff; + if (n >= 51) { /* |x| >= 2**51 */ + if (n >= 1024) +#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN) + *s = *c = ix >= 0x7ff80000 ? x : x - x; + /* assumes sparc-like QNaN */ +#else + *s = *c = x - x; +#endif + else { + if (n >= 53) { + *s = 0.0; + *c = 1.0; + } + else if (n == 52) { + if ((lx & 1) == 0) { + *s = 0.0; + *c = 1.0; + } + else { + *s = -0.0; + *c = -1.0; + } + } + else { /* n == 51 */ + if ((lx & 1) == 0) { + *s = 0.0; + *c = 1.0; + } + else { + *s = 1.0; + *c = 0.0; + } + if ((lx & 2) != 0) { + *s = -*s; + *c = -*c; + } + } + } + } + else if (n < -2) /* |x| < 0.25 */ + *s = __k_sincos(pi * fabs(x), 0.0, c); + else { + /* y = |4x|, z = floor(y), and n = (int)(z mod 8.0) */ + if (ix < 0x41C00000) { /* |x| < 2**29 */ + y = 4.0 * fabs(x); + n = (int) y; /* exact */ + z = (double) n; + k = z == y; + t = (y - z) * 0.25; + } + else { /* 2**29 <= |x| < 2**51 */ + y = fabs(x); + k = 50 - n; + n = lx >> k; + h = n << k; + ((unsigned *) &z)[LOWORD] = h; + ((int *) &z)[HIWORD] = ix; + k = h == lx; + t = y - z; + } + if (k) { /* x = N/4 */ + if ((n & 1) != 0) + *s = *c = sqrth_h + sqrth_l; + else + if ((n & 2) == 0) { + *s = 0.0; + *c = 1.0; + } + else { + *s = 1.0; + *c = 0.0; + } + y = (n & 2) == 0 ? 0.0 : 1.0; + if ((n & 4) != 0) + *s = -*s; + if (((n + 1) & 4) != 0) + *c = -*c; + } + else { + if ((n & 1) != 0) + t = 0.25 - t; + if (((n + (n & 1)) & 2) == 0) + *s = __k_sincos(pi * t, 0.0, c); + else + *c = __k_sincos(pi * t, 0.0, s); + if ((n & 4) != 0) + *s = -*s; + if (((n + 2) & 4) != 0) + *c = -*c; + } + } + if (hx < 0) + *s = -*s; +} |