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Diffstat (limited to 'usr/src/lib/libm/common/Q/cosl.c')
-rw-r--r-- | usr/src/lib/libm/common/Q/cosl.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/Q/cosl.c b/usr/src/lib/libm/common/Q/cosl.c new file mode 100644 index 0000000000..bea6b35b37 --- /dev/null +++ b/usr/src/lib/libm/common/Q/cosl.c @@ -0,0 +1,94 @@ +/* + * 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. + */ + +/* + * cosl(x) + * Table look-up algorithm by K.C. Ng, November, 1989. + * + * kernel function: + * __k_sinl ... sin function on [-pi/4,pi/4] + * __k_cosl ... cos function on [-pi/4,pi/4] + * __rem_pio2l ... argument reduction routine + * + * Method. + * Let S and C denote the sin and cos respectively on [-PI/4, +PI/4]. + * 1. Assume the argument x is reduced to y1+y2 = x-k*pi/2 in + * [-pi/2 , +pi/2], and let n = k mod 4. + * 2. Let S=S(y1+y2), C=C(y1+y2). Depending on n, we have + * + * n sin(x) cos(x) tan(x) + * ---------------------------------------------------------- + * 0 S C S/C + * 1 C -S -C/S + * 2 -S -C S/C + * 3 -C S -C/S + * ---------------------------------------------------------- + * + * Special cases: + * Let trig be any of sin, cos, or tan. + * trig(+-INF) is NaN, with signals; + * trig(NaN) is that NaN; + * + * Accuracy: + * computer TRIG(x) returns trig(x) nearly rounded. + */ + +#pragma weak cosl = __cosl + +#include "libm.h" +#include "longdouble.h" + +long double +cosl(long double x) { + long double y[2], z = 0.0L; + int n, ix; + + ix = *(int *) &x; /* High word of x */ + + ix &= 0x7fffffff; + if (ix <= 0x3ffe9220) /* |x| ~< pi/4 */ + return (__k_cosl(x, z)); + else if (ix >= 0x7fff0000) /* trig(Inf or NaN) is NaN */ + return (x - x); + else { /* argument reduction needed */ + n = __rem_pio2l(x, y); + switch (n & 3) { + case 0: + return (__k_cosl(y[0], y[1])); + case 1: + return (-__k_sinl(y[0], y[1])); + case 2: + return (-__k_cosl(y[0], y[1])); + case 3: + return (__k_sinl(y[0], y[1])); + } + } + /* NOTREACHED */ + return 0.0L; +} |