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54 lines
1.5 KiB
C
54 lines
1.5 KiB
C
/* Round to nearest integer value, rounding halfway cases to even.
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Copyright (C) 2017-2021 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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#define NO_MATH_REDIRECT
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#include <math.h>
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#include <fenv_private.h>
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#include <libm-alias-double.h>
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#include <stdint.h>
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double
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__roundeven (double x)
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{
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int flags = riscv_getflags ();
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bool nan = isnan (x);
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double mag = fabs (x);
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if (nan)
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return x + x;
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if (mag < (1ULL << __DBL_MANT_DIG__))
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{
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int64_t i;
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double new_x;
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asm volatile ("fcvt.l.d %0, %1, rne" : "=r" (i) : "f" (x));
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asm volatile ("fcvt.d.l %0, %1, rne" : "=f" (new_x) : "r" (i));
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/* roundeven(-0) == -0, and in general we'll always have the same
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sign as our input. */
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x = copysign (new_x, x);
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riscv_setflags (flags);
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}
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return x;
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}
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libm_alias_double (__roundeven, roundeven)
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