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f962932206
C23 adds various <math.h> function families originally defined in TS 18661-4. Add the asinpi functions (asin(x)/pi). Tested for x86_64 and x86, and with build-many-glibcs.py.
46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
/* Return arc sine of X, divided by pi.
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Copyright (C) 2024 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-narrow-eval.h>
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#include <math_private.h>
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#include <math-underflow.h>
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FLOAT
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M_DECL_FUNC (__asinpi) (FLOAT x)
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{
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if (__glibc_unlikely (!islessequal (M_FABS (x), M_LIT (1.0))))
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{
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if (!isnan (x))
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__set_errno (EDOM);
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return (x - x) / (x - x);
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}
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FLOAT ret = math_narrow_eval (M_SUF (__ieee754_asin) (x) / M_MLIT (M_PI));
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math_check_force_underflow (ret);
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if (x != 0 && ret == 0)
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__set_errno (ERANGE);
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/* Ensure that rounding away from zero for both asin and the
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division cannot yield a return value from asinpi with absolute
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value greater than 0.5. */
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return (isgreater (M_FABS (ret), M_LIT (0.5))
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? M_COPYSIGN (M_LIT (0.5), ret)
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: ret);
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}
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declare_mgen_alias (__asinpi, asinpi);
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