LXR linux/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
  21long 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}
  46EXPORT_SYMBOL(__ashrdi3);
  47