Files
kernel-tenderloin-3.0/include/linux
David Howells f0d1b0b30d [PATCH] LOG2: Implement a general integer log2 facility in the kernel
This facility provides three entry points:

	ilog2()		Log base 2 of unsigned long
	ilog2_u32()	Log base 2 of u32
	ilog2_u64()	Log base 2 of u64

These facilities can either be used inside functions on dynamic data:

	int do_something(long q)
	{
		...;
		y = ilog2(x)
		...;
	}

Or can be used to statically initialise global variables with constant values:

	unsigned n = ilog2(27);

When performing static initialisation, the compiler will report "error:
initializer element is not constant" if asked to take a log of zero or of
something not reducible to a constant.  They treat negative numbers as
unsigned.

When not dealing with a constant, they fall back to using fls() which permits
them to use arch-specific log calculation instructions - such as BSR on
x86/x86_64 or SCAN on FRV - if available.

[akpm@osdl.org: MMC fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:51 -08:00
..
2006-09-26 17:40:24 -04:00
2006-12-08 08:28:47 -08:00
2006-12-07 08:39:25 -08:00
2006-12-04 02:00:22 -05:00
2006-10-03 23:01:26 +02:00
2006-09-28 17:53:58 -07:00
2006-12-02 21:22:55 -08:00
2006-12-02 21:22:55 -08:00
2006-12-02 21:22:55 -08:00
2006-12-06 20:14:22 -08:00
2006-10-03 23:01:26 +02:00
2006-10-04 19:32:09 +02:00
2006-12-08 08:28:39 -08:00
2006-12-07 08:39:37 -08:00
2006-12-07 08:39:20 -08:00
2006-12-08 08:28:39 -08:00
2006-11-22 14:57:56 +00:00
2006-12-06 18:38:54 -08:00
2006-12-02 21:30:59 -08:00
2006-12-07 08:39:25 -08:00
2006-10-03 08:04:16 -07:00
2006-07-03 19:44:51 -07:00
2006-09-26 08:48:54 -07:00
2006-09-22 15:18:47 -07:00
2006-12-07 08:39:32 -08:00
2006-07-28 21:02:00 -07:00
2006-10-02 07:57:12 -07:00
2006-12-07 08:39:21 -08:00
2006-09-26 17:40:24 -04:00
2006-09-26 15:38:52 -07:00
2006-09-28 18:02:13 -07:00
2006-12-02 21:21:24 -08:00
2006-12-02 21:21:17 -08:00
2006-12-04 02:00:34 -05:00
2006-12-02 21:21:21 -08:00
2006-09-28 18:02:29 -07:00
2006-11-24 00:43:09 -05:00
2006-12-07 08:39:20 -08:00
2006-10-11 11:14:23 -07:00
2006-10-10 15:37:22 -07:00
2006-08-21 10:02:50 +02:00
2006-12-02 21:21:21 -08:00
2006-10-04 07:55:12 -07:00
2006-12-07 08:39:47 -08:00
2006-12-07 08:39:47 -08:00
2006-12-07 08:39:47 -08:00
2006-10-04 00:31:09 -07:00
2006-12-02 21:21:21 -08:00
2006-11-30 05:24:39 +01:00
2006-11-30 04:53:49 +01:00
2006-07-31 15:44:29 -04:00
2006-10-11 11:14:15 -07:00
2006-12-08 08:28:39 -08:00
2006-11-30 04:40:22 +01:00
2006-09-28 18:02:22 -07:00
2006-11-16 11:43:38 -08:00
2006-11-22 14:57:56 +00:00
2006-12-02 21:22:57 -08:00
2006-12-04 02:00:34 -05:00
2006-12-02 21:22:56 -08:00
2006-12-06 10:46:38 -05:00
2006-12-07 02:14:01 +01:00
2006-08-27 11:01:32 -07:00
2006-10-03 08:03:40 -07:00
2006-06-28 15:54:27 -07:00
2006-11-03 12:27:58 -08:00
2006-07-03 19:48:25 -07:00
2006-12-04 02:00:36 -05:00
2006-10-03 23:01:26 +02:00
2006-12-07 08:39:36 -08:00
2006-10-02 07:57:15 -07:00
2006-09-26 08:49:04 -07:00
2006-12-07 08:39:25 -08:00
2006-12-08 08:28:38 -08:00
2006-12-02 21:26:16 -08:00
2006-12-02 21:21:34 -08:00
2006-12-07 08:39:35 -08:00
2006-12-07 08:39:30 -08:00
2006-12-07 08:39:25 -08:00
2006-12-07 08:39:25 -08:00
2006-10-10 16:15:34 -07:00
2006-12-07 08:39:20 -08:00
2006-10-01 00:39:18 -07:00
2006-10-01 00:39:19 -07:00
2006-10-11 11:14:21 -07:00
2006-11-30 05:32:19 +01:00
2006-10-06 08:53:40 -07:00
2006-12-02 21:21:08 -08:00
2006-09-28 17:53:59 -07:00
2006-12-08 08:28:38 -08:00
2006-10-01 00:39:19 -07:00
2006-10-04 07:55:12 -07:00
2006-09-29 09:18:13 -07:00
2006-12-02 00:11:58 -05:00
2006-10-09 14:20:38 -07:00