LXR linux/arch/x86/boot/bitops.h

   1/* -*- linux-c -*- ------------------------------------------------------- *
   2 *
   3 *   Copyright (C) 1991, 1992 Linus Torvalds
   4 *   Copyright 2007 rPath, Inc. - All Rights Reserved
   5 *
   6 *   This file is part of the Linux kernel, and is made available under
   7 *   the terms of the GNU General Public License version 2.
   8 *
   9 * ----------------------------------------------------------------------- */
  10
  11/*
  12 * Very simple bitops for the boot code.
  13 */
  14
  15#ifndef BOOT_BITOPS_H
  16#define BOOT_BITOPS_H
  17#define _LINUX_BITOPS_H         /* Inhibit inclusion of <linux/bitops.h> */
  18
  19#include <linux/types.h>
  20
  21static inline bool constant_test_bit(int nr, const void *addr)
  22{
  23        const u32 *p = (const u32 *)addr;
  24        return ((1UL << (nr & 31)) & (p[nr >> 5])) != 0;
  25}
  26static inline bool variable_test_bit(int nr, const void *addr)
  27{
  28        bool v;
  29        const u32 *p = (const u32 *)addr;
  30
  31        asm("btl %2,%1; setc %0" : "=qm" (v) : "m" (*p), "Ir" (nr));
  32        return v;
  33}
  34
  35#define test_bit(nr,addr) \
  36(__builtin_constant_p(nr) ? \
  37 constant_test_bit((nr),(addr)) : \
  38 variable_test_bit((nr),(addr)))
  39
  40static inline void set_bit(int nr, void *addr)
  41{
  42        asm("btsl %1,%0" : "+m" (*(u32 *)addr) : "Ir" (nr));
  43}
  44
  45#endif /* BOOT_BITOPS_H */
  46