linux/arch/mn10300/lib/ashrdi3.c
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   1/* ashrdi3.c extracted from gcc-2.7.2/libgcc2.c which is: */
   2/* Copyright (C) 1989, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   3
   4This file is part of GNU CC.
   5
   6GNU CC is free software; you can redistribute it and/or modify
   7it under the terms of the GNU General Public Licence as published by
   8the Free Software Foundation; either version 2, or (at your option)
   9any later version.
  10
  11GNU CC is distributed in the hope that it will be useful,
  12but WITHOUT ANY WARRANTY; without even the implied warranty of
  13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14GNU General Public Licence for more details.
  15
  16You should have received a copy of the GNU General Public Licence
  17along with GNU CC; see the file COPYING.  If not, write to
  18the Free Software Foundation, 59 Temple Place - Suite 330,
  19Boston, MA 02111-1307, USA.  */
  20
  21#define BITS_PER_UNIT 8
  22
  23typedef          int SItype     __attribute__((mode(SI)));
  24typedef unsigned int USItype    __attribute__((mode(SI)));
  25typedef          int DItype     __attribute__((mode(DI)));
  26typedef          int word_type  __attribute__((mode(__word__)));
  27
  28struct DIstruct {
  29        SItype low;
  30        SItype high;
  31};
  32
  33union DIunion {
  34        struct DIstruct s;
  35        DItype          ll;
  36};
  37
  38DItype __ashrdi3(DItype u, word_type b)
  39{
  40        union DIunion w;
  41        union DIunion uu;
  42        word_type bm;
  43
  44        if (b == 0)
  45                return u;
  46
  47        uu.ll = u;
  48
  49        bm = (sizeof(SItype) * BITS_PER_UNIT) - b;
  50        if (bm <= 0) {
  51                /* w.s.high = 1..1 or 0..0 */
  52                w.s.high = uu.s.high >> (sizeof(SItype) * BITS_PER_UNIT - 1);
  53                w.s.low = uu.s.high >> -bm;
  54        } else {
  55                USItype carries = (USItype)uu.s.high << bm;
  56                w.s.high = uu.s.high >> b;
  57                w.s.low = ((USItype)uu.s.low >> b) | carries;
  58        }
  59
  60        return w.ll;
  61}
  62