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71 lines
1.7 KiB
C
71 lines
1.7 KiB
C
/* s_cosf.c -- float version of s_cos.c.
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Copyright (C) 2011-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Adhemerval Zanella <azanella@br.ibm.com>, 2011
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, see <http://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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static const float one = 1.0;
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static const float pio4 = 7.8539801e-1;
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float
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__cosf (float x)
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{
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float y[2], z = 0.0;
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float ix;
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int32_t n;
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ix = __builtin_fabsf (x);
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/* |x| ~< pi/4 */
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if (ix <= pio4)
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{
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return __kernel_cosf (x, z);
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/* cos(Inf or NaN) is NaN */
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}
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else if (isnanf (ix))
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{
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return x - x;
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}
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else if (isinff (ix))
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{
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__set_errno (EDOM);
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return x - x;
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}
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/* argument reduction needed */
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else
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{
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n = __ieee754_rem_pio2f (x, y);
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switch (n & 3)
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{
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case 0:
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return __kernel_cosf (y[0], y[1]);
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case 1:
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return -__kernel_sinf (y[0], y[1], 1);
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case 2:
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return -__kernel_cosf (y[0], y[1]);
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default:
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return __kernel_sinf (y[0], y[1], 1);
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}
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}
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}
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weak_alias (__cosf, cosf)
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