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
  19static inline int constant_test_bit(int nr, const void *addr)
  20{
  21        const u32 *p = (const u32 *)addr;
  22        return ((1UL << (nr & 31)) & (p[nr >> 5])) != 0;
  23}
  24static inline int variable_test_bit(int nr, const void *addr)
  25{
  26        u8 v;
  27        const u32 *p = (const u32 *)addr;
  28
  29        asm("btl %2,%1; setc %0" : "=qm" (v) : "m" (*p), "Ir" (nr));
  30        return v;
  31}
  32
  33#define test_bit(nr,addr) \
  34(__builtin_constant_p(nr) ? \
  35 constant_test_bit((nr),(addr)) : \
  36 variable_test_bit((nr),(addr)))
  37
  38static inline void set_bit(int nr, void *addr)
  39{
  40        asm("btsl %1,%0" : "+m" (*(u32 *)addr) : "Ir" (nr));
  41}
  42
  43#endif /* BOOT_BITOPS_H */
  44