arch/mn10300/lib/bitops.c

   1 /* MN10300 Non-trivial bit operations
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11 #include <linux/module.h>
  12 #include <asm/bitops.h>
  13
  14 /*
  15  * try flipping a bit using BSET and BCLR
  16  */
  17 void change_bit(unsigned long nr, volatile void *addr)
  18 {
  19         if (test_bit(nr, addr))
  20                 goto try_clear_bit;
  21
  22 try_set_bit:
  23         if (!test_and_set_bit(nr, addr))
  24                 return;
  25
  26 try_clear_bit:
  27         if (test_and_clear_bit(nr, addr))
  28                 return;
  29
  30         goto try_set_bit;
  31 }
  32
  33 /*
  34  * try flipping a bit using BSET and BCLR and returning the old value
  35  */
  36 int test_and_change_bit(unsigned long nr, volatile void *addr)
  37 {
  38         if (test_bit(nr, addr))
  39                 goto try_clear_bit;
  40
  41 try_set_bit:
  42         if (!test_and_set_bit(nr, addr))
  43                 return 0;
  44
  45 try_clear_bit:
  46         if (test_and_clear_bit(nr, addr))
  47                 return 1;
  48
  49         goto try_set_bit;
  50 }