102 lines
3.3 KiB
C
102 lines
3.3 KiB
C
/*-
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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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* 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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/*
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* The code has been taken from FreeBSD (sys/libkern/ucmpdi2.c) and is therefore
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* BSD-licensed. Unnecessary functions have been removed and all typedefs required
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* have been added.
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*/
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#include <metalsvm/stddef.h>
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#define CHAR_BIT 8
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#if BYTE_ORDER == LITTLE_ENDIAN
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#define _QUAD_HIGHWORD 1
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#define _QUAD_LOWWORD 0
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#else
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#define _QUAD_HIGHWORD 0
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#define _QUAD_LOWWORD 1
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#endif
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/*
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* Define high and low longwords.
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*/
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#define H _QUAD_HIGHWORD
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#define L _QUAD_LOWWORD
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/*
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* Total number of bits in a quad_t and in the pieces that make it up.
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* These are used for shifting, and also below for halfword extraction
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* and assembly.
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*/
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#define QUAD_BITS (sizeof(quad_t) * CHAR_BIT)
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#define LONG_BITS (sizeof(long) * CHAR_BIT)
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#define HALF_BITS (sizeof(long) * CHAR_BIT / 2)
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typedef int64_t quad_t;
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typedef uint32_t qshift_t;
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/*
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* Depending on the desired operation, we view a `long long' (aka quad_t) in
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* one or more of the following formats.
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*/
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union uu {
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quad_t q; /* as a (signed) quad */
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quad_t uq; /* as an unsigned quad */
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int32_t sl[2]; /* as two signed longs */
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uint32_t ul[2]; /* as two unsigned longs */
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};
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/*
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* Shift an (unsigned) quad value right (logical shift right).
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*/
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quad_t
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__lshrdi3(a, shift)
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quad_t a;
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qshift_t shift;
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{
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union uu aa;
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aa.q = a;
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if (shift >= LONG_BITS) {
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aa.ul[L] = shift >= QUAD_BITS ? 0 :
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aa.ul[H] >> (shift - LONG_BITS);
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aa.ul[H] = 0;
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} else if (shift > 0) {
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aa.ul[L] = (aa.ul[L] >> shift) |
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(aa.ul[H] << (LONG_BITS - shift));
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aa.ul[H] >>= shift;
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}
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return (aa.q);
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}
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