| 1 | /*-
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| 2 | * Copyright (c) 1990, 1993
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| 3 | * The Regents of the University of California. All rights reserved.
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| 4 | *
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| 5 | * This code is derived from software contributed to Berkeley by
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| 6 | * Sean Eric Fagan.
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| 7 | *
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| 8 | * Redistribution and use in source and binary forms, with or without
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| 9 | * modification, are permitted provided that the following conditions
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| 10 | * are met:
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| 11 | * 1. Redistributions of source code must retain the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer.
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer in the
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| 15 | * documentation and/or other materials provided with the distribution.
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| 16 | * 3. All advertising materials mentioning features or use of this software
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| 17 | * must display the following acknowledgement:
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| 18 | * This product includes software developed by the University of
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| 19 | * California, Berkeley and its contributors.
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| 20 | * 4. Neither the name of the University nor the names of its contributors
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| 21 | * may be used to endorse or promote products derived from this software
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| 22 | * without specific prior written permission.
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| 23 | *
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| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 34 | * SUCH DAMAGE.
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| 35 | */
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| 36 |
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| 37 | #if defined(LIBC_SCCS) && !defined(lint)
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| 38 | static char sccsid[] = "@(#)ldexp.c 8.1 (Berkeley) 6/4/93";
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| 39 | #endif /* LIBC_SCCS and not lint */
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| 40 | #include <sys/cdefs.h>
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| 41 | __FBSDID("$FreeBSD: src/lib/libc/i386/gen/ldexp.c,v 1.11 2004/02/16 10:03:02 das Exp $");
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| 42 |
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| 43 | /*
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| 44 | * ldexp(value, exp): return value * (2 ** exp).
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| 45 | *
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| 46 | * Written by Sean Eric Fagan (sef@kithrup.COM)
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| 47 | * Sun Mar 11 20:27:09 PST 1990
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| 48 | */
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| 49 |
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| 50 | /*
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| 51 | * We do the conversion in C to let gcc optimize it away, if possible.
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| 52 | */
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| 53 | double
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| 54 | ldexp (double value, int exp)
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| 55 | {
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| 56 | double temp, texp, temp2;
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| 57 | texp = exp;
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| 58 | #ifdef __GNUC__
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| 59 | __asm ("fscale "
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| 60 | : "=u" (temp2), "=t" (temp)
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| 61 | : "0" (texp), "1" (value));
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| 62 | #else
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| 63 | #error unknown asm
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| 64 | #endif
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| 65 | return (temp);
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| 66 | }
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