arch/mn10300/lib/ashrdi3.c

   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
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public Licence as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public Licence for more details.
  15
  16 You should have received a copy of the GNU General Public Licence
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #define BITS_PER_UNIT 8
  22
  23 typedef          int SItype     __attribute__((mode(SI)));
  24 typedef unsigned int USItype    __attribute__((mode(SI)));
  25 typedef          int DItype     __attribute__((mode(DI)));
  26 typedef          int word_type  __attribute__((mode(__word__)));
  27
  28 struct DIstruct {
  29         SItype low;
  30         SItype high;
  31 };
  32
  33 union DIunion {
  34         struct DIstruct s;
  35         DItype          ll;
  36 };
  37
  38 DItype __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 }