glibc/sysdeps/ieee754/dbl-64/s_sincos.c
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105 lines
2.4 KiB
C

/* Compute sine and cosine of argument.
Copyright (C) 1997-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <math.h>
#include <math_private.h>
#include <fenv_private.h>
#include <math-underflow.h>
#include <libm-alias-double.h>
#define IN_SINCOS
#include "s_sin.c"
void
__sincos (double x, double *sinx, double *cosx)
{
mynumber u;
int k;
SET_RESTORE_ROUND_53BIT (FE_TONEAREST);
u.x = x;
k = u.i[HIGH_HALF] & 0x7fffffff;
if (k < 0x400368fd)
{
double a, da, y;
/* |x| < 2^-27 => cos (x) = 1, sin (x) = x. */
if (k < 0x3e400000)
{
if (k < 0x3e500000)
math_check_force_underflow (x);
*sinx = x;
*cosx = 1.0;
return;
}
/* |x| < 0.855469. */
else if (k < 0x3feb6000)
{
*sinx = do_sin (x, 0);
*cosx = do_cos (x, 0);
return;
}
/* |x| < 2.426265. */
y = hp0 - fabs (x);
a = y + hp1;
da = (y - a) + hp1;
*sinx = copysign (do_cos (a, da), x);
*cosx = do_sin (a, da);
return;
}
/* |x| < 2^1024. */
if (k < 0x7ff00000)
{
double a, da, xx;
unsigned int n;
/* If |x| < 105414350 use simple range reduction. */
n = k < 0x419921FB ? reduce_sincos (x, &a, &da) : __branred (x, &a, &da);
n = n & 3;
if (n == 1 || n == 2)
{
a = -a;
da = -da;
}
if (n & 1)
{
double *temp = cosx;
cosx = sinx;
sinx = temp;
}
*sinx = do_sin (a, da);
xx = do_cos (a, da);
*cosx = (n & 2) ? -xx : xx;
return;
}
if (isinf (x))
__set_errno (EDOM);
*sinx = *cosx = x / x;
}
libm_alias_double (__sincos, sincos)