diff options
| author | Bob Pearson <rpearson@systemfabricworks.com> | 2012-03-23 23:02:24 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-24 00:58:37 +0100 |
| commit | 324eb0f17d9dcead3c60c133aa244f6b3631fec9 (patch) | |
| tree | 657c564269a0fc1921f4252dbf0184725f5c85fa /lib/crc32defs.h | |
| parent | crc32: make CRC_*_BITS definition correspond to actual bit counts (diff) | |
| download | linux-324eb0f17d9dcead3c60c133aa244f6b3631fec9.tar.xz linux-324eb0f17d9dcead3c60c133aa244f6b3631fec9.zip | |
crc32: add slice-by-8 algorithm to existing code
Add slicing-by-8 algorithm to the existing slicing-by-4 algorithm. This
consists of:
- extend largest BITS size from 32 to 64
- extend tables from tab[4][256] to up to tab[8][256]
- Add code for inner loop.
[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson <rpearson@systemfabricworks.com>
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/crc32defs.h')
| -rw-r--r-- | lib/crc32defs.h | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/lib/crc32defs.h b/lib/crc32defs.h index daa3a5e85f60..818159288489 100644 --- a/lib/crc32defs.h +++ b/lib/crc32defs.h @@ -6,29 +6,42 @@ #define CRCPOLY_LE 0xedb88320 #define CRCPOLY_BE 0x04c11db7 -/* How many bits at a time to use. Valid values are 1, 2, 4, 8, and 32. */ -/* For less performance-sensitive, use 4 or 8 */ +/* + * How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64. + * For less performance-sensitive, use 4 or 8 to save table size. + * For larger systems choose same as CPU architecture as default. + * This works well on X86_64, SPARC64 systems. This may require some + * elaboration after experiments with other architectures. + */ #ifndef CRC_LE_BITS -# define CRC_LE_BITS 32 +# ifdef CONFIG_64BIT +# define CRC_LE_BITS 64 +# else +# define CRC_LE_BITS 32 +# endif #endif #ifndef CRC_BE_BITS -# define CRC_BE_BITS 32 +# ifdef CONFIG_64BIT +# define CRC_BE_BITS 64 +# else +# define CRC_BE_BITS 32 +# endif #endif /* * Little-endian CRC computation. Used with serial bit streams sent * lsbit-first. Be sure to use cpu_to_le32() to append the computed CRC. */ -#if CRC_LE_BITS > 32 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \ +#if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \ CRC_LE_BITS & CRC_LE_BITS-1 -# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32}" +# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}" #endif /* * Big-endian CRC computation. Used with serial bit streams sent * msbit-first. Be sure to use cpu_to_be32() to append the computed CRC. */ -#if CRC_BE_BITS > 32 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \ +#if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \ CRC_BE_BITS & CRC_BE_BITS-1 -# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32}" +# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}" #endif |