11a058bb6d
a bit, but access to a freebsd/sparc64 machine is needed. Submitted by: bde and Steve Kargl <sgk@apl.washington.edu> (earlier version)
62 lines
1.9 KiB
C
62 lines
1.9 KiB
C
/* From: @(#)k_cos.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("$FreeBSD$");
|
|
|
|
/*
|
|
* ld128 version of k_cos.c. See ../src/k_cos.c for most comments.
|
|
*/
|
|
|
|
#include "math_private.h"
|
|
|
|
/*
|
|
* Domain [-0.7854, 0.7854], range ~[-1.80e-37, 1.79e-37]:
|
|
* |cos(x) - c(x))| < 2**-122.0
|
|
*
|
|
* 113-bit precision requires more care than 64-bit precision, since
|
|
* simple methods give a minimax polynomial with coefficient for x^2
|
|
* that is 1 ulp below 0.5, but we want it to be precisely 0.5. See
|
|
* ../ld80/k_cosl.c for more details.
|
|
*/
|
|
static const double
|
|
one = 1.0;
|
|
|
|
static const long double
|
|
C1 = 0.04166666666666666666666666666666658424671L,
|
|
C2 = -0.001388888888888888888888888888863490893732L,
|
|
C3 = 0.00002480158730158730158730158600795304914210L,
|
|
C4 = -0.2755731922398589065255474947078934284324e-6L,
|
|
C5 = 0.2087675698786809897659225313136400793948e-8L,
|
|
C6 = -0.1147074559772972315817149986812031204775e-10L,
|
|
C7 = 0.4779477332386808976875457937252120293400e-13L;
|
|
|
|
static const double
|
|
C8 = -0.1561920696721507929516718307820958119868e-15,
|
|
C9 = 0.4110317413744594971475941557607804508039e-18,
|
|
C10 = -0.8896592467191938803288521958313920156409e-21,
|
|
C11 = 0.1601061435794535138244346256065192782581e-23;
|
|
|
|
long double
|
|
__kernel_cosl(long double x, long double y)
|
|
{
|
|
long double hz,z,r,w;
|
|
|
|
z = x*x;
|
|
r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*(C6+z*(C7+
|
|
z*(C8+z*(C9+z*(C10+z*C11))))))))));
|
|
hz = 0.5*z;
|
|
w = one-hz;
|
|
return w + (((one-w)-hz) + (z*r-x*y));
|
|
}
|