minix/lib/libc/quad/fixdfdi_ieee754.c

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/* $NetBSD: fixdfdi_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $ */
/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
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*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: fixdfdi_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#if defined(SOFTFLOAT) || defined(__ARM_EABI__)
#include "softfloat/softfloat-for-gcc.h"
#endif
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#include "quad.h"
#include <limits.h>
#include <stdbool.h>
#include <machine/ieee.h>
/*
* Convert double to signed quad.
* Not sure what to do with negative numbers---for now, anything out
* of range becomes UQUAD_MAX.
*/
quad_t
__fixdfdi(double x)
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{
const union ieee_double_u ux = { .dblu_d = x };
signed int exp = ux.dblu_exp - DBL_EXP_BIAS;
const bool neg = ux.dblu_sign;
quad_t r;
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if (exp >= 62)
return neg ? QUAD_MIN : QUAD_MAX;
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r = 1 << DBL_FRACHBITS; /* implicit bit */
r |= ux.dblu_frach;
exp -= DBL_FRACHBITS;
if (exp < 0) {
r >>= -exp;
} else if (exp > 0) {
r <<= DBL_FRACLBITS;
r |= ux.dblu_fracl;
exp -= DBL_FRACLBITS;
if (exp < 0) {
r >>= -exp;
} else if (exp > 0) {
r <<= exp;
}
}
return neg ? -r : r;
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}