freebsd-dev/lib/msun/ld80/k_sinl.c
David Schultz de336b0c5e Add kernel functions for 80-bit long doubles. Many thanks to Steve and
Bruce for putting lots of effort into these; getting them right isn't
easy, and they went through many iterations.

Submitted by:	Steve Kargl <sgk@apl.washington.edu> with revisions from bde
2008-02-17 07:32:14 +00:00

63 lines
1.9 KiB
C

/* From: @(#)k_sin.c 1.3 95/01/18 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
* Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans.
*
* Developed at SunSoft, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* ld80 version of k_sin.c. See ../src/k_sin.c for most comments.
*/
#include "math_private.h"
static const double
half = 0.5;
/*
* Domain [-0.7854, 0.7854], range ~[-1.89e-22, 1.915e-22]
* |sin(x)/x - s(x)| < 2**-72.1
*
* See ../ld80/k_cosl.c for more details about the polynomial.
*/
#if defined(__amd64__) || defined(__i386__)
/* Long double constants are slow on these arches, and broken on i386. */
static const volatile double
S1hi = -0.16666666666666666, /* -0x15555555555555.0p-55 */
S1lo = -9.2563760475949941e-18; /* -0x15580000000000.0p-109 */
#define S1 ((long double)S1hi + S1lo)
#else
static const long double
S1 = -0.166666666666666666671L; /* -0xaaaaaaaaaaaaaaab.0p-66 */
#endif
static const double
S2 = 0.0083333333333333332, /* 0x11111111111111.0p-59 */
S3 = -0.00019841269841269427, /* -0x1a01a01a019f81.0p-65 */
S4 = 0.0000027557319223597490, /* 0x171de3a55560f7.0p-71 */
S5 = -0.000000025052108218074604, /* -0x1ae64564f16cad.0p-78 */
S6 = 1.6059006598854211e-10, /* 0x161242b90243b5.0p-85 */
S7 = -7.6429779983024564e-13, /* -0x1ae42ebd1b2e00.0p-93 */
S8 = 2.6174587166648325e-15; /* 0x179372ea0b3f64.0p-101 */
long double
__kernel_sinl(long double x, long double y, int iy)
{
long double z,r,v;
z = x*x;
v = z*x;
r = S2+z*(S3+z*(S4+z*(S5+z*(S6+z*(S7+z*S8)))));
if(iy==0) return x+v*(S1+z*r);
else return x-((z*(half*y-v*r)-y)-v*S1);
}