/*-
* Copyright (c) 2017-2023 Steven G. Kargl
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* See ../src/s_cospi.c for implementation details.
*/
#include "math.h"
#include "math_private.h"
/*
* pi_hi contains the leading 56 bits of a 169 bit approximation for pi.
*/
static const long double
pi_hi = 3.14159265358979322702026593105983920e+00L,
pi_lo = 1.14423774522196636802434264184180742e-17L;
#include "k_cospil.h"
#include "k_sinpil.h"
static volatile const double vzero = 0;
long double
cospil(long double x)
{
long double ai, ar, ax, c;
ax = fabsl(x);
if (ax <= 1) {
if (ax < 0.25) {
if (ax < 0x1p-60) {
if ((int)x == 0)
return (1);
}
return (__kernel_cospil(ax));
}
if (ax < 0.5)
c = __kernel_sinpil(0.5 - ax);
else if (ax < 0.75) {
if (ax == 0.5)
return (0);
c = -__kernel_sinpil(ax - 0.5);
} else
c = -__kernel_cospil(1 - ax);
return (c);
}
if (ax < 0x1p112) {
/* Split ax = ai + ar with 0 <= ar < 1. */
FFLOORL128(ax, ai, ar);
if (ar < 0.5) {
if (ar < 0.25)
c = ar == 0 ? 1 : __kernel_cospil(ar);
else
c = __kernel_sinpil(0.5 - ar);
} else {
if (ar < 0.75) {
if (ar == 0.5)
return (0);
c = -__kernel_sinpil(ar - 0.5);
} else
c = -__kernel_cospil(1 - ar);
}
return (fmodl(ai, 2.L) == 0 ? c : -c);
}
if (isinf(x) || isnan(x))
return (vzero / vzero);
/*
* For |x| >= 0x1p113, it is always an even integer, so return 1.
*/
if (ax >= 0x1p113)
return (1);
/*
* For 0x1p112 <= |x| < 0x1p113 need to determine if x is an even
* or odd integer to return 1 or -1.
*/
