mirror of https://gitee.com/openkylin/linux.git
62 lines
1.6 KiB
C
62 lines
1.6 KiB
C
/* ashrdi3.c extracted from gcc-2.7.2/libgcc2.c which is: */
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/* Copyright (C) 1989, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public Licence as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public Licence for more details.
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You should have received a copy of the GNU General Public Licence
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#define BITS_PER_UNIT 8
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typedef int SItype __attribute__((mode(SI)));
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typedef unsigned int USItype __attribute__((mode(SI)));
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typedef int DItype __attribute__((mode(DI)));
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typedef int word_type __attribute__((mode(__word__)));
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struct DIstruct {
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SItype low;
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SItype high;
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};
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union DIunion {
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struct DIstruct s;
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DItype ll;
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};
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DItype __ashrdi3(DItype u, word_type b)
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{
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union DIunion w;
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union DIunion uu;
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word_type bm;
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if (b == 0)
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return u;
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uu.ll = u;
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bm = (sizeof(SItype) * BITS_PER_UNIT) - b;
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if (bm <= 0) {
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/* w.s.high = 1..1 or 0..0 */
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w.s.high = uu.s.high >> (sizeof(SItype) * BITS_PER_UNIT - 1);
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w.s.low = uu.s.high >> -bm;
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} else {
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USItype carries = (USItype)uu.s.high << bm;
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w.s.high = uu.s.high >> b;
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w.s.low = ((USItype)uu.s.low >> b) | carries;
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}
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return w.ll;
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}
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