| 1 | /* $NetBSD: subdi3.c,v 1.9 2005/12/11 12:24:37 christos Exp $ */
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| 2 |
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| 3 | /*-
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| 4 | * Copyright (c) 1992, 1993
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| 5 | * The Regents of the University of California. All rights reserved.
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| 6 | *
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| 7 | * This software was developed by the Computer Systems Engineering group
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| 8 | * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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| 9 | * contributed to Berkeley.
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| 10 | *
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| 11 | * Redistribution and use in source and binary forms, with or without
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| 12 | * modification, are permitted provided that the following conditions
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| 13 | * are met:
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| 14 | * 1. Redistributions of source code must retain the above copyright
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| 15 | * notice, this list of conditions and the following disclaimer.
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| 16 | * 2. Redistributions in binary form must reproduce the above copyright
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| 17 | * notice, this list of conditions and the following disclaimer in the
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| 18 | * documentation and/or other materials provided with the distribution.
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| 19 | * 3. Neither the name of the University nor the names of its contributors
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| 20 | * may be used to endorse or promote products derived from this software
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| 21 | * without specific prior written permission.
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| 22 | *
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| 23 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 24 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 25 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 26 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 27 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 28 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 29 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 30 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 31 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 32 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 33 | * SUCH DAMAGE.
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| 34 | */
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| 35 |
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| 36 | /*#include <sys/cdefs.h>
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| 37 | #if defined(LIBC_SCCS) && !defined(lint)
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| 38 | #if 0
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| 39 | static char sccsid[] = "@(#)subdi3.c 8.1 (Berkeley) 6/4/93";
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| 40 | #else
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| 41 | __RCSID("$NetBSD: subdi3.c,v 1.9 2005/12/11 12:24:37 christos Exp $");
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| 42 | #endif
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| 43 | #endif*/ /* LIBC_SCCS and not lint */
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| 44 |
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| 45 | #include "quad.h"
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| 46 |
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| 47 | /*
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| 48 | * Subtract two quad values. This is trivial since a one-bit carry
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| 49 | * from a single u_int difference x-y occurs if and only if (x-y) > x.
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| 50 | */
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| 51 | quad_t
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| 52 | __subdi3(a, b)
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| 53 | quad_t a, b;
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| 54 | {
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| 55 | union uu aa, bb, diff;
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| 56 |
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| 57 | aa.q = a;
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| 58 | bb.q = b;
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| 59 | diff.ul[L] = aa.ul[L] - bb.ul[L];
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| 60 | diff.ul[H] = aa.ul[H] - bb.ul[H] - (diff.ul[L] > aa.ul[L]);
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| 61 | return (diff.q);
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| 62 | }
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