crc32: add slice-by-8 algorithm to existing code

[thirdparty/linux.git] / lib / gen_crc32table.c

diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c
index 99ac744848fb49ffe7303c1046d0e3bcf7cfa383..0d9edd17ee13bb35fa4f409a3c7bf73e1591f4c4 100644 (file)
--- 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");
        }