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authorAkinobu Mita <mita@miraclelinux.com>2006-03-26 04:39:12 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-26 11:57:11 -0500
commit6d29ea23da033f46ac4ab359d46650a7f7474611 (patch)
tree20403ba836b8e5e7ace71cae914bbc16d552a4bd /include/asm-generic
parentc7f612cdf091def01454e7e132c7d7a3f419fbc4 (diff)
[PATCH] bitops: generic sched_find_first_bit()
This patch introduces the C-language equivalent of the function: int sched_find_first_bit(const unsigned long *b); In include/asm-generic/bitops/sched.h This code largely copied from: include/asm-powerpc/bitops.h Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/bitops/sched.h36
1 files changed, 36 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/sched.h b/include/asm-generic/bitops/sched.h
new file mode 100644
index 000000000000..5ef93a4d009f
--- /dev/null
+++ b/include/asm-generic/bitops/sched.h
@@ -0,0 +1,36 @@
1#ifndef _ASM_GENERIC_BITOPS_SCHED_H_
2#define _ASM_GENERIC_BITOPS_SCHED_H_
3
4#include <linux/compiler.h> /* unlikely() */
5#include <asm/types.h>
6
7/*
8 * Every architecture must define this function. It's the fastest
9 * way of searching a 140-bit bitmap where the first 100 bits are
10 * unlikely to be set. It's guaranteed that at least one of the 140
11 * bits is cleared.
12 */
13static inline int sched_find_first_bit(const unsigned long *b)
14{
15#if BITS_PER_LONG == 64
16 if (unlikely(b[0]))
17 return __ffs(b[0]);
18 if (unlikely(b[1]))
19 return __ffs(b[1]) + 64;
20 return __ffs(b[2]) + 128;
21#elif BITS_PER_LONG == 32
22 if (unlikely(b[0]))
23 return __ffs(b[0]);
24 if (unlikely(b[1]))
25 return __ffs(b[1]) + 32;
26 if (unlikely(b[2]))
27 return __ffs(b[2]) + 64;
28 if (b[3])
29 return __ffs(b[3]) + 96;
30 return __ffs(b[4]) + 128;
31#else
32#error BITS_PER_LONG not defined
33#endif
34}
35
36#endif /* _ASM_GENERIC_BITOPS_SCHED_H_ */