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kernel/linux-imx6_3.14.28/arch/mn10300/lib/bitops.c 1.06 KB
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6b13f685e   김민수   BSP 최초 추가 
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  /* MN10300 Non-trivial bit operations
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public Licence
   * as published by the Free Software Foundation; either version
   * 2 of the Licence, or (at your option) any later version.
   */
  #include <linux/module.h>
  #include <asm/bitops.h>
  
  /*
   * try flipping a bit using BSET and BCLR
   */
  void change_bit(unsigned long nr, volatile void *addr)
  {
  	if (test_bit(nr, addr))
  		goto try_clear_bit;
  
  try_set_bit:
  	if (!test_and_set_bit(nr, addr))
  		return;
  
  try_clear_bit:
  	if (test_and_clear_bit(nr, addr))
  		return;
  
  	goto try_set_bit;
  }
  
  /*
   * try flipping a bit using BSET and BCLR and returning the old value
   */
  int test_and_change_bit(unsigned long nr, volatile void *addr)
  {
  	if (test_bit(nr, addr))
  		goto try_clear_bit;
  
  try_set_bit:
  	if (!test_and_set_bit(nr, addr))
  		return 0;
  
  try_clear_bit:
  	if (test_and_clear_bit(nr, addr))
  		return 1;
  
  	goto try_set_bit;
  }