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67 lines
2.0 KiB
C
67 lines
2.0 KiB
C
/* Round a double value to a long long in the current rounding mode.
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Copyright (C) 1997-2020 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 <limits.h>
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#include <math.h>
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#include <math_ldbl_opt.h>
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#include <math_private.h>
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#include <stdint.h>
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#include <libm-alias-double.h>
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long long int
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__llrint (double x)
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{
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#ifdef _ARCH_PWR4
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/* Assume powerpc64 instructions availability. */
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long long int ret;
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__asm__ ("fctid %0, %1" : "=d" (ret) : "d" (x));
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return ret;
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#else
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double rx = rint (x);
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if (HAVE_PPC_FCTIDZ || rx != x)
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return (long long int) rx;
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else
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{
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/* Avoid incorrect exceptions from libgcc conversions (as of GCC
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5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>. */
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if (fabs (rx) < 0x1p31)
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return (long long int) (long int) rx;
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uint64_t i0;
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EXTRACT_WORDS64 (i0, rx);
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int exponent = ((i0 >> 52) & 0x7ff) - 0x3ff;
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if (exponent < 63)
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{
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unsigned long long int mant
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= (i0 & ((1ULL << 52) - 1)) | (1ULL << 52);
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if (exponent < 52)
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mant >>= 52 - exponent;
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else
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mant <<= exponent - 52;
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return (long long int) ((i0 & (1ULL << 63)) != 0 ? -mant : mant);
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}
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else if (rx == (double) LLONG_MIN)
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return LLONG_MIN;
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else
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return (long long int) (long int) rx << 32;
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}
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#endif
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}
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#ifndef __llrint
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libm_alias_double (__llrint, llrint)
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#endif
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