diff options
author | Akinobu Mita <mita@miraclelinux.com> | 2006-03-26 04:39:12 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-26 11:57:11 -0500 |
commit | 6d29ea23da033f46ac4ab359d46650a7f7474611 (patch) | |
tree | 20403ba836b8e5e7ace71cae914bbc16d552a4bd /include/asm-generic | |
parent | c7f612cdf091def01454e7e132c7d7a3f419fbc4 (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.h | 36 |
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 | */ | ||
13 | static 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_ */ | ||