xref: /linux/arch/x86/boot/bitops.h (revision 0dd9ac63ce26ec87b080ca9c3e6efed33c23ace6)
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 static 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 }
24 static 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 
38 static 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