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/*-
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 * Copyright (c) 1992, 1993
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 *      The Regents of the University of California.  All rights reserved.
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 *
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 * This software was developed by the Computer Systems Engineering group
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 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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 * contributed to Berkeley.
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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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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *      This product includes software developed by the University of
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 *      California, Berkeley and its contributors.
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 * 4. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)fixunssfdi.c        8.1 (Berkeley) 6/4/93";
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#endif /* LIBC_SCCS and not lint */
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#include "quad.h"
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#define ONE_FOURTH      (1 << (LONG_BITS - 2))
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#define ONE_HALF        (ONE_FOURTH * 2.0)
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#define ONE             (ONE_FOURTH * 4.0)
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/*
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 * Convert float to (unsigned) quad.  We do most of our work in double,
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 * out of sheer paranoia.
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 *
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 * Not sure what to do with negative numbers---for now, anything out
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 * of range becomes UQUAD_MAX.
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 *
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 * N.B.: must use new ANSI syntax (sorry).
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 */
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u_quad_t
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__fixunssfdi(float f)
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{
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        double x, toppart;
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        union uu t;
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        if (f < 0)
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                return (UQUAD_MAX);     /* ??? should be 0?  ERANGE??? */
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#ifdef notdef                           /* this falls afoul of a GCC bug */
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        if (f >= UQUAD_MAX)
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                return (UQUAD_MAX);
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#else                                   /* so we wire in 2^64-1 instead */
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        if (f >= 18446744073709551615.0)
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                return (UQUAD_MAX);
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#endif
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        x = f;
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        /*
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         * Get the upper part of the result.  Note that the divide
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         * may round up; we want to avoid this if possible, so we
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         * subtract `1/2' first.
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         */
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        toppart = (x - ONE_HALF) / ONE;
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        /*
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         * Now build a u_quad_t out of the top part.  The difference
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         * between x and this is the bottom part (this may introduce
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         * a few fuzzy bits, but what the heck).  With any luck this
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         * difference will be nonnegative: x should wind up in the
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         * range [0..ULONG_MAX].  For paranoia, we assume [LONG_MIN..
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         * 2*ULONG_MAX] instead.
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         */
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        t.ul[H] = (unsigned long)toppart;
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        t.ul[L] = 0;
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        x -= (double)t.uq;
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        if (x < 0) {
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                t.ul[H]--;
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                x += ULONG_MAX;
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        }
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        if (x > ULONG_MAX) {
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                t.ul[H]++;
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                x -= ULONG_MAX;
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        }
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        t.ul[L] = (u_long)x;
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        return (t.uq);
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}