From 324eb0f17d9dcead3c60c133aa244f6b3631fec9 Mon Sep 17 00:00:00 2001 From: Bob Pearson Date: Fri, 23 Mar 2012 15:02:24 -0700 Subject: 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 Signed-off-by: Darrick J. Wong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/gen_crc32table.c | 43 +++++++++++++++++++++++++++---------------- 1 file changed, 27 insertions(+), 16 deletions(-) (limited to 'lib/gen_crc32table.c') diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c index 99ac744848f..0d9edd17ee1 100644 --- a/lib/gen_crc32table.c +++ b/lib/gen_crc32table.c @@ -1,23 +1,28 @@ #include +#include "../include/generated/autoconf.h" #include "crc32defs.h" #include #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"); } -- cgit v1.2.3