lib/ashrdi3.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, see the file COPYING, or write
  14  * to the Free Software Foundation, Inc.
  15  */
  16
  17 #include <linux/export.h>
  18
  19 #include <linux/libgcc.h>
  20
  21 long long notrace __ashrdi3(long long u, word_type b)
  22 {
  23         DWunion uu, w;
  24         word_type bm;
  25
  26         if (b == 0)
  27                 return u;
  28
  29         uu.ll = u;
  30         bm = 32 - b;
  31
  32         if (bm <= 0) {
  33                 /* w.s.high = 1..1 or 0..0 */
  34                 w.s.high =
  35                     uu.s.high >> 31;
  36                 w.s.low = uu.s.high >> -bm;
  37         } else {
  38                 const unsigned int carries = (unsigned int) uu.s.high << bm;
  39
  40                 w.s.high = uu.s.high >> b;
  41                 w.s.low = ((unsigned int) uu.s.low >> b) | carries;
  42         }
  43
  44         return w.ll;
  45 }
  46 EXPORT_SYMBOL(__ashrdi3);