arch/blackfin/lib/lshrdi3.c

   1 /*
   2  * File:         arch/blackfin/lib/lshrdi3.c
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #define BITS_PER_UNIT 8
  31
  32 typedef int SItype __attribute__ ((mode(SI)));
  33 typedef unsigned int USItype __attribute__ ((mode(SI)));
  34 typedef int DItype __attribute__ ((mode(DI)));
  35 typedef int word_type __attribute__ ((mode(__word__)));
  36
  37 struct DIstruct {
  38         SItype high, low;
  39 };
  40
  41 typedef union {
  42         struct DIstruct s;
  43         DItype ll;
  44 } DIunion;
  45
  46 #ifdef CONFIG_ARITHMETIC_OPS_L1
  47 DItype __lshrdi3(DItype u, word_type b)__attribute__((l1_text));
  48 #endif
  49
  50 DItype __lshrdi3(DItype u, word_type b)
  51 {
  52         DIunion w;
  53         word_type bm;
  54         DIunion uu;
  55
  56         if (b == 0)
  57                 return u;
  58
  59         uu.ll = u;
  60
  61         bm = (sizeof(SItype) * BITS_PER_UNIT) - b;
  62         if (bm <= 0) {
  63                 w.s.high = 0;
  64                 w.s.low = (USItype) uu.s.high >> -bm;
  65         } else {
  66                 USItype carries = (USItype) uu.s.high << bm;
  67                 w.s.high = (USItype) uu.s.high >> b;
  68                 w.s.low = ((USItype) uu.s.low >> b) | carries;
  69         }
  70
  71         return w.ll;
  72 }