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89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
/* Round argument to nearest integral value according to current rounding
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direction.
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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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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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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 <fenv.h>
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#include <limits.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 <libm-alias-float.h>
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#include <fix-fp-int-convert-overflow.h>
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static const float two23[2] =
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{
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8.3886080000e+06, /* 0x4B000000 */
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-8.3886080000e+06, /* 0xCB000000 */
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};
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long int
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__lrintf (float x)
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{
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int32_t j0;
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uint32_t i0;
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float w;
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float t;
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long int result;
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int sx;
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GET_FLOAT_WORD (i0, x);
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sx = i0 >> 31;
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j0 = ((i0 >> 23) & 0xff) - 0x7f;
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i0 &= 0x7fffff;
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i0 |= 0x800000;
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if (j0 < (int32_t) (sizeof (long int) * 8) - 1)
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{
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if (j0 >= 23)
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result = (long int) i0 << (j0 - 23);
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else
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{
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w = math_narrow_eval (two23[sx] + x);
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t = w - two23[sx];
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GET_FLOAT_WORD (i0, t);
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j0 = ((i0 >> 23) & 0xff) - 0x7f;
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i0 &= 0x7fffff;
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i0 |= 0x800000;
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result = (j0 < 0 ? 0 : i0 >> (23 - j0));
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}
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}
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else
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{
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#ifdef FE_INVALID
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/* The number is too large. Unless it rounds to LONG_MIN,
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FE_INVALID must be raised and the return value is
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unspecified. */
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if (FIX_FLT_LONG_CONVERT_OVERFLOW && x != (float) LONG_MIN)
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{
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feraiseexcept (FE_INVALID);
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return sx == 0 ? LONG_MAX : LONG_MIN;
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}
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#endif
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return (long int) x;
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}
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return sx ? -result : result;
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}
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libm_alias_float (__lrint, lrint)
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