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55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/* Round a float 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 <math.h>
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#include <math_private.h>
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#include <stdint.h>
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#include <libm-alias-float.h>
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long long int
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__llrintf (float 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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float rx = rintf (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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float arx = fabsf (rx);
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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 (arx < 0x1p31f)
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return (long long int) (long int) rx;
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else if (!(arx < 0x1p55f))
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return (long long int) (long int) (rx * 0x1p-32f) << 32;
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uint32_t i0;
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GET_FLOAT_WORD (i0, rx);
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int exponent = ((i0 >> 23) & 0xff) - 0x7f;
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unsigned long long int mant = (i0 & 0x7fffff) | 0x800000;
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mant <<= exponent - 23;
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return (long long int) ((i0 & 0x80000000) != 0 ? -mant : mant);
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}
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#endif
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}
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libm_alias_float (__llrint, llrint)
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