diff options
author | Chanho Min <chanho.min@lge.com> | 2013-07-08 16:01:43 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-09 10:33:30 -0700 |
commit | 4df87bb7b6a22dfc6fdd5abb3dd362b3af2c164d (patch) | |
tree | e7e065ee0e172184fc7dc8f96a508518836e38f2 /lib/clz_ctz.c | |
parent | 1b3a5d02ee070c8f9943333b9b6370f486601e0f (diff) | |
download | linux-stable-4df87bb7b6a22dfc6fdd5abb3dd362b3af2c164d.tar.gz linux-stable-4df87bb7b6a22dfc6fdd5abb3dd362b3af2c164d.tar.bz2 linux-stable-4df87bb7b6a22dfc6fdd5abb3dd362b3af2c164d.zip |
lib: add weak clz/ctz functions
Some architectures need __c[lt]z[sd]i2() for __builtin_c[lt]z[ll] and
that causes a build failure. They can be implemented using the
fls()/__ffs() and overridden by linking arch-specific versions may not
be implemented yet.
This is required by "lib: add lz4 compressor module".
Reference: https://lkml.org/lkml/2013/4/18/603
Signed-off-by: Chanho Min <chanho.min@lge.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: Yann Collet <yann.collet.73@gmail.com>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/clz_ctz.c')
-rw-r--r-- | lib/clz_ctz.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/lib/clz_ctz.c b/lib/clz_ctz.c new file mode 100644 index 000000000000..a8f8379eb49f --- /dev/null +++ b/lib/clz_ctz.c @@ -0,0 +1,58 @@ +/* + * lib/clz_ctz.c + * + * Copyright (C) 2013 Chanho Min <chanho.min@lge.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions. + */ + +#include <linux/export.h> +#include <linux/kernel.h> + +int __weak __ctzsi2(int val) +{ + return __ffs(val); +} +EXPORT_SYMBOL(__ctzsi2); + +int __weak __clzsi2(int val) +{ + return 32 - fls(val); +} +EXPORT_SYMBOL(__clzsi2); + +#if BITS_PER_LONG == 32 + +int __weak __clzdi2(long val) +{ + return 32 - fls((int)val); +} +EXPORT_SYMBOL(__clzdi2); + +int __weak __ctzdi2(long val) +{ + return __ffs((u32)val); +} +EXPORT_SYMBOL(__ctzdi2); + +#elif BITS_PER_LONG == 64 + +int __weak __clzdi2(long val) +{ + return 64 - fls64((u64)val); +} +EXPORT_SYMBOL(__clzdi2); + +int __weak __ctzdi2(long val) +{ + return __ffs64((u64)val); +} +EXPORT_SYMBOL(__ctzdi2); + +#else +#error BITS_PER_LONG not 32 or 64 +#endif |