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authorBob Pearson <rpearson@systemfabricworks.com>2012-03-23 15:02:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-23 16:58:37 -0700
commit324eb0f17d9dcead3c60c133aa244f6b3631fec9 (patch)
tree657c564269a0fc1921f4252dbf0184725f5c85fa /lib/gen_crc32table.c
parent9a1dbf6a29694c9d81b498019f103aee0f8b5b6c (diff)
downloadlwn-324eb0f17d9dcead3c60c133aa244f6b3631fec9.tar.gz
lwn-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/gen_crc32table.c')
-rw-r--r--lib/gen_crc32table.c43
1 files changed, 27 insertions, 16 deletions
diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c
index 99ac744848fb..0d9edd17ee13 100644
--- a/lib/gen_crc32table.c
+++ b/lib/gen_crc32table.c
@@ -1,23 +1,28 @@
#include <stdio.h>
+#include "../include/generated/autoconf.h"
#include "crc32defs.h"
#include <inttypes.h>
#define ENTRIES_PER_LINE 4
-#if CRC_LE_BITS <= 8
-#define LE_TABLE_SIZE (1 << CRC_LE_BITS)
+#if CRC_LE_BITS > 8
+# define LE_TABLE_ROWS (CRC_LE_BITS/8)
+# define LE_TABLE_SIZE 256
#else
-#define LE_TABLE_SIZE 256
+# define LE_TABLE_ROWS 1
+# define LE_TABLE_SIZE (1 << CRC_LE_BITS)
#endif
-#if CRC_BE_BITS <= 8
-#define BE_TABLE_SIZE (1 << CRC_BE_BITS)
+#if CRC_BE_BITS > 8
+# define BE_TABLE_ROWS (CRC_BE_BITS/8)
+# define BE_TABLE_SIZE 256
#else
-#define BE_TABLE_SIZE 256
+# define BE_TABLE_ROWS 1
+# define BE_TABLE_SIZE (1 << CRC_BE_BITS)
#endif
-static uint32_t crc32table_le[4][256];
-static uint32_t crc32table_be[4][256];
+static uint32_t crc32table_le[LE_TABLE_ROWS][256];
+static uint32_t crc32table_be[BE_TABLE_ROWS][256];
/**
* crc32init_le() - allocate and initialize LE table data
@@ -40,7 +45,7 @@ static void crc32init_le(void)
}
for (i = 0; i < LE_TABLE_SIZE; i++) {
crc = crc32table_le[0][i];
- for (j = 1; j < 4; j++) {
+ for (j = 1; j < LE_TABLE_ROWS; j++) {
crc = crc32table_le[0][crc & 0xff] ^ (crc >> 8);
crc32table_le[j][i] = crc;
}
@@ -64,18 +69,18 @@ static void crc32init_be(void)
}
for (i = 0; i < BE_TABLE_SIZE; i++) {
crc = crc32table_be[0][i];
- for (j = 1; j < 4; j++) {
+ for (j = 1; j < BE_TABLE_ROWS; j++) {
crc = crc32table_be[0][(crc >> 24) & 0xff] ^ (crc << 8);
crc32table_be[j][i] = crc;
}
}
}
-static void output_table(uint32_t (*table)[256], int len, char *trans)
+static void output_table(uint32_t (*table)[256], int rows, int len, char *trans)
{
int i, j;
- for (j = 0 ; j < 4; j++) {
+ for (j = 0 ; j < rows; j++) {
printf("{");
for (i = 0; i < len - 1; i++) {
if (i % ENTRIES_PER_LINE == 0)
@@ -92,15 +97,21 @@ int main(int argc, char** argv)
if (CRC_LE_BITS > 1) {
crc32init_le();
- printf("static const u32 crc32table_le[4][256] = {");
- output_table(crc32table_le, LE_TABLE_SIZE, "tole");
+ printf("static const u32 __cacheline_aligned "
+ "crc32table_le[%d][%d] = {",
+ LE_TABLE_ROWS, LE_TABLE_SIZE);
+ output_table(crc32table_le, LE_TABLE_ROWS,
+ LE_TABLE_SIZE, "tole");
printf("};\n");
}
if (CRC_BE_BITS > 1) {
crc32init_be();
- printf("static const u32 crc32table_be[4][256] = {");
- output_table(crc32table_be, BE_TABLE_SIZE, "tobe");
+ printf("static const u32 __cacheline_aligned "
+ "crc32table_be[%d][%d] = {",
+ BE_TABLE_ROWS, BE_TABLE_SIZE);
+ output_table(crc32table_be, LE_TABLE_ROWS,
+ BE_TABLE_SIZE, "tobe");
printf("};\n");
}