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| 2 | pj | 1 | /*- |
| 2 | * Copyright (c) 1992, 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 software was developed by the Computer Systems Engineering group |
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| 6 | * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and |
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| 7 | * contributed to Berkeley. |
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| 8 | * |
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| 9 | * Redistribution and use in source and binary forms, with or without |
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| 10 | * modification, are permitted provided that the following conditions |
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| 11 | * are met: |
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| 12 | * 1. Redistributions of source code must retain the above copyright |
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| 13 | * notice, this list of conditions and the following disclaimer. |
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| 14 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 15 | * notice, this list of conditions and the following disclaimer in the |
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| 16 | * documentation and/or other materials provided with the distribution. |
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| 17 | * 3. All advertising materials mentioning features or use of this software |
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| 18 | * must display the following acknowledgement: |
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| 19 | * This product includes software developed by the University of |
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| 20 | * California, Berkeley and its contributors. |
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| 21 | * 4. Neither the name of the University nor the names of its contributors |
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| 22 | * may be used to endorse or promote products derived from this software |
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| 23 | * without specific prior written permission. |
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| 24 | * |
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| 25 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| 26 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 27 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 28 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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| 29 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 30 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| 31 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 32 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 33 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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| 34 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 35 | * SUCH DAMAGE. |
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| 36 | */ |
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| 37 | |||
| 38 | #if defined(LIBC_SCCS) && !defined(lint) |
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| 39 | static char sccsid[] = "@(#)ashrdi3.c 8.1 (Berkeley) 6/4/93"; |
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| 40 | #endif /* LIBC_SCCS and not lint */ |
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| 41 | |||
| 42 | #include "quad.h" |
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| 43 | |||
| 44 | /* |
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| 45 | * Shift a (signed) quad value right (arithmetic shift right). |
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| 46 | */ |
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| 47 | quad_t |
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| 48 | __ashrdi3(a, shift) |
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| 49 | quad_t a; |
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| 50 | qshift_t shift; |
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| 51 | { |
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| 52 | union uu aa; |
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| 53 | |||
| 54 | aa.q = a; |
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| 55 | if (shift >= LONG_BITS) { |
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| 56 | long s; |
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| 57 | |||
| 58 | /* |
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| 59 | * Smear bits rightward using the machine's right-shift |
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| 60 | * method, whether that is sign extension or zero fill, |
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| 61 | * to get the `sign word' s. Note that shifting by |
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| 62 | * LONG_BITS is undefined, so we shift (LONG_BITS-1), |
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| 63 | * then 1 more, to get our answer. |
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| 64 | */ |
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| 65 | s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1; |
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| 66 | aa.ul[L] = shift >= QUAD_BITS ? s : |
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| 67 | aa.sl[H] >> (shift - LONG_BITS); |
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| 68 | aa.ul[H] = s; |
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| 69 | } else if (shift > 0) { |
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| 70 | aa.ul[L] = (aa.ul[L] >> shift) | |
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| 71 | (aa.ul[H] << (LONG_BITS - shift)); |
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| 72 | aa.sl[H] >>= shift; |
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| 73 | } |
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| 74 | return (aa.q); |
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| 75 | } |