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  * arch/i386/boot/bitops.h
  13  *
  14  * Very simple bitops for the boot code.
  15  */
  16
  17 #ifndef BOOT_BITOPS_H
  18 #define BOOT_BITOPS_H
  19 #define _LINUX_BITOPS_H         /* Inhibit inclusion of <linux/bitops.h> */
  20
  21 static inline int 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 }
  26 static inline int variable_test_bit(int nr, const void *addr)
  27 {
  28         u8 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
  40 static 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 */