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The compiler may substitute calls to sin or cos with calls to sincos, thus we should have the same optimized implementations for sincos. The optimized implementations may produce results that differ, that also makes sure that the sincos call aggrees with the sin and cos calls.
111 lines
2.4 KiB
C
111 lines
2.4 KiB
C
/* Compute sine and cosine of argument.
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Copyright (C) 1997-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <math.h>
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#include <math_private.h>
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#include <fenv_private.h>
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#include <math-underflow.h>
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#include <libm-alias-double.h>
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#ifndef SECTION
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# define SECTION
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#endif
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#define IN_SINCOS
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#include "s_sin.c"
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void
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SECTION
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__sincos (double x, double *sinx, double *cosx)
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{
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mynumber u;
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int k;
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SET_RESTORE_ROUND_53BIT (FE_TONEAREST);
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u.x = x;
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k = u.i[HIGH_HALF] & 0x7fffffff;
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if (k < 0x400368fd)
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{
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double a, da, y;
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/* |x| < 2^-27 => cos (x) = 1, sin (x) = x. */
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if (k < 0x3e400000)
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{
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if (k < 0x3e500000)
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math_check_force_underflow (x);
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*sinx = x;
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*cosx = 1.0;
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return;
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}
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/* |x| < 0.855469. */
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else if (k < 0x3feb6000)
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{
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*sinx = do_sin (x, 0);
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*cosx = do_cos (x, 0);
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return;
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}
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/* |x| < 2.426265. */
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y = hp0 - fabs (x);
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a = y + hp1;
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da = (y - a) + hp1;
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*sinx = copysign (do_cos (a, da), x);
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*cosx = do_sin (a, da);
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return;
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}
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/* |x| < 2^1024. */
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if (k < 0x7ff00000)
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{
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double a, da, xx;
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unsigned int n;
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/* If |x| < 105414350 use simple range reduction. */
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n = k < 0x419921FB ? reduce_sincos (x, &a, &da) : __branred (x, &a, &da);
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n = n & 3;
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if (n == 1 || n == 2)
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{
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a = -a;
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da = -da;
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}
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if (n & 1)
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{
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double *temp = cosx;
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cosx = sinx;
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sinx = temp;
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}
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*sinx = do_sin (a, da);
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xx = do_cos (a, da);
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*cosx = (n & 2) ? -xx : xx;
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return;
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}
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if (isinf (x))
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__set_errno (EDOM);
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*sinx = *cosx = x / x;
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}
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#ifndef __sincos
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libm_alias_double (__sincos, sincos)
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#endif
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