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crc32: bolt on crc32c

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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>
This commit is contained in:
Darrick J. Wong
2012-03-23 15:02:25 -07:00
committed by Linus Torvalds
parent 78dff41897
commit 46c5801eaf
5 changed files with 97 additions and 34 deletions
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35
lib/gen_crc32table.c
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@@ -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;
}