mirror of git://sourceware.org/git/glibc.git
48 lines
1.6 KiB
C
48 lines
1.6 KiB
C
/* Return sine of pi * X.
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Copyright (C) 2024-2025 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-underflow.h>
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FLOAT
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M_DECL_FUNC (__sinpi) (FLOAT x)
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{
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if (isless (M_FABS (x), M_EPSILON))
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{
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FLOAT ret = M_MLIT (M_PI) * x;
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math_check_force_underflow (ret);
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return ret;
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}
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if (__glibc_unlikely (isinf (x)))
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__set_errno (EDOM);
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FLOAT y = x - M_LIT (2.0) * M_SUF (round) (M_LIT (0.5) * x);
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FLOAT absy = M_FABS (y);
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if (absy == M_LIT (0.0) || absy == M_LIT (1.0))
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return M_COPYSIGN (M_LIT (0.0), x);
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else if (islessequal (absy, M_LIT (0.25)))
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return M_SUF (__sin) (M_MLIT (M_PI) * y);
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else if (islessequal (absy, M_LIT (0.75)))
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return M_COPYSIGN (M_SUF (__cos) (M_MLIT (M_PI) * (M_LIT (0.5) - absy)),
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y);
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else
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return M_COPYSIGN (M_SUF (__sin) (M_MLIT (M_PI) * (M_LIT (1.0) - absy)),
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y);
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}
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declare_mgen_alias (__sinpi, sinpi);
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