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3374de9038
C23 adds various <math.h> function families originally defined in TS 18661-4. Add the atan2pi functions (atan2(y,x)/pi). Tested for x86_64 and x86, and with build-many-glibcs.py.
42 lines
1.5 KiB
C
42 lines
1.5 KiB
C
/* Return arc tangent of Y/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 (__atan2pi) (FLOAT y, FLOAT x)
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{
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FLOAT ret = math_narrow_eval (M_SUF (__ieee754_atan2) (y, x)
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/ M_MLIT (M_PI));
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if (__glibc_likely (!isnan (ret)))
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math_check_force_underflow (ret);
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if (ret == 0 && y != 0 && isfinite (x))
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__set_errno (ERANGE);
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/* Ensure that rounding away from zero for both atan2 and the
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division cannot yield a return value from atan2pi with absolute
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value greater than 1. */
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return (isgreater (M_FABS (ret), M_LIT (1.0))
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? M_COPYSIGN (M_LIT (1.0), ret)
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: ret);
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}
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declare_mgen_alias (__atan2pi, atan2pi);
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