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| author | Darrick J. Wong <djwong@us.ibm.com> | 2012-03-23 15:02:25 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-23 16:58:38 -0700 |
| commit | 46c5801eaf86e83cb3a4142ad35188db5011fff0 (patch) | |
| tree | 2b8a8f7709aa7dadafdf13f823488cf51e2e2fed /lib/gen_crc32table.c | |
| parent | 78dff4189708d07cdcaf7bfd1b04ebe78ac9c041 (diff) | |
| download | lwn-46c5801eaf86e83cb3a4142ad35188db5011fff0.tar.gz lwn-46c5801eaf86e83cb3a4142ad35188db5011fff0.zip | |
crc32: bolt on crc32c
Reuse the existing crc32 code to stamp out a crc32c implementation.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/gen_crc32table.c')
| -rw-r--r-- | lib/gen_crc32table.c | 35 |
1 files changed, 28 insertions, 7 deletions
diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c index 0d9edd17ee13..8f8d5439e2d9 100644 --- a/lib/gen_crc32table.c +++ b/lib/gen_crc32table.c @@ -23,6 +23,7 @@ static uint32_t crc32table_le[LE_TABLE_ROWS][256]; static uint32_t crc32table_be[BE_TABLE_ROWS][256]; +static uint32_t crc32ctable_le[LE_TABLE_ROWS][256]; /** * crc32init_le() - allocate and initialize LE table data @@ -31,27 +32,38 @@ static uint32_t crc32table_be[BE_TABLE_ROWS][256]; * fact that crctable[i^j] = crctable[i] ^ crctable[j]. * */ -static void crc32init_le(void) +static void crc32init_le_generic(const uint32_t polynomial, + uint32_t (*tab)[256]) { unsigned i, j; uint32_t crc = 1; - crc32table_le[0][0] = 0; + tab[0][0] = 0; for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) { - crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0); + crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0); for (j = 0; j < LE_TABLE_SIZE; j += 2 * i) - crc32table_le[0][i + j] = crc ^ crc32table_le[0][j]; + tab[0][i + j] = crc ^ tab[0][j]; } for (i = 0; i < LE_TABLE_SIZE; i++) { - crc = crc32table_le[0][i]; + crc = tab[0][i]; for (j = 1; j < LE_TABLE_ROWS; j++) { - crc = crc32table_le[0][crc & 0xff] ^ (crc >> 8); - crc32table_le[j][i] = crc; + crc = tab[0][crc & 0xff] ^ (crc >> 8); + tab[j][i] = crc; } } } +static void crc32init_le(void) +{ + crc32init_le_generic(CRCPOLY_LE, crc32table_le); +} + +static void crc32cinit_le(void) +{ + crc32init_le_generic(CRC32C_POLY_LE, crc32ctable_le); +} + /** * crc32init_be() - allocate and initialize BE table data */ @@ -114,6 +126,15 @@ int main(int argc, char** argv) BE_TABLE_SIZE, "tobe"); printf("};\n"); } + if (CRC_LE_BITS > 1) { + crc32cinit_le(); + printf("static const u32 __cacheline_aligned " + "crc32ctable_le[%d][%d] = {", + LE_TABLE_ROWS, LE_TABLE_SIZE); + output_table(crc32ctable_le, LE_TABLE_ROWS, + LE_TABLE_SIZE, "tole"); + printf("};\n"); + } return 0; } |