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/* $OpenBSD: s_lround.c,v 1.8 2016/09/12 19:47:02 guenther Exp $ */ |
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/* $NetBSD: lround.c,v 1.2 2004/10/13 15:18:32 drochner Exp $ */ |
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/*- |
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* Copyright (c) 2004 |
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* Matthias Drochner. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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#include <sys/types.h> |
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#include <sys/limits.h> |
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#include <float.h> |
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#include <math.h> |
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#include <ieeefp.h> |
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#include <machine/ieee.h> |
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#include "math_private.h" |
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#ifndef LROUNDNAME |
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#define LROUNDNAME lround |
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#define RESTYPE long int |
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#define RESTYPE_MIN LONG_MIN |
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#define RESTYPE_MAX LONG_MAX |
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#endif |
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#define RESTYPE_BITS (sizeof(RESTYPE) * 8) |
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RESTYPE |
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LROUNDNAME(double x) |
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{ |
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u_int32_t i0, i1; |
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int e, s, shift; |
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RESTYPE res; |
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GET_HIGH_WORD(i0, x); |
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e = i0 >> DBL_FRACHBITS; |
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s = e >> DBL_EXPBITS; |
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e = (e & 0x7ff) - DBL_EXP_BIAS; |
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/* 1.0 x 2^-1 is the smallest number which can be rounded to 1 */ |
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✓✓ |
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if (e < -1) |
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return (0); |
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/* 1.0 x 2^31 (or 2^63) is already too large */ |
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✓✓ |
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if (e >= (int)RESTYPE_BITS - 1) |
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return (s ? RESTYPE_MIN : RESTYPE_MAX); /* ??? unspecified */ |
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/* >= 2^52 is already an exact integer */ |
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✓✓ |
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if (e < DBL_FRACBITS) { |
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/* add 0.5, extraction below will truncate */ |
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x += (s ? -0.5 : 0.5); |
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} |
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EXTRACT_WORDS(i0, i1, x); |
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e = ((i0 >> DBL_FRACHBITS) & 0x7ff) - DBL_EXP_BIAS; |
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i0 &= 0xfffff; |
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i0 |= (1 << DBL_FRACHBITS); |
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shift = e - DBL_FRACBITS; |
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✓✓ |
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if (shift >=0) |
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✓✗ |
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res = (shift < RESTYPE_BITS ? (RESTYPE)i1 << shift : 0); |
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else |
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✓✗ |
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res = (shift > -RESTYPE_BITS ? (RESTYPE)i1 >> -shift : 0); |
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shift += 32; |
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✓✓ |
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if (shift >=0) |
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✓✗ |
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res |= (shift < RESTYPE_BITS ? (RESTYPE)i0 << shift : 0); |
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else |
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✓✗ |
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res |= (shift > -RESTYPE_BITS ? (RESTYPE)i0 >> -shift : 0); |
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return (s ? -res : res); |
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} |
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DEF_STD(LROUNDNAME); |
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LDBL_MAYBE_UNUSED_CLONE(LROUNDNAME); |