diff options
Diffstat (limited to 'lib/gen_crc64table.c')
-rw-r--r-- | lib/gen_crc64table.c | 51 |
1 files changed, 40 insertions, 11 deletions
diff --git a/lib/gen_crc64table.c b/lib/gen_crc64table.c index 094b43aef8db..55e222acd0b8 100644 --- a/lib/gen_crc64table.c +++ b/lib/gen_crc64table.c @@ -17,10 +17,30 @@ #include <stdio.h> #define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL +#define CRC64_ROCKSOFT_POLY 0x9A6C9329AC4BC9B5ULL static uint64_t crc64_table[256] = {0}; +static uint64_t crc64_rocksoft_table[256] = {0}; -static void generate_crc64_table(void) +static void generate_reflected_crc64_table(uint64_t table[256], uint64_t poly) +{ + uint64_t i, j, c, crc; + + for (i = 0; i < 256; i++) { + crc = 0ULL; + c = i; + + for (j = 0; j < 8; j++) { + if ((crc ^ (c >> j)) & 1) + crc = (crc >> 1) ^ poly; + else + crc >>= 1; + } + table[i] = crc; + } +} + +static void generate_crc64_table(uint64_t table[256], uint64_t poly) { uint64_t i, j, c, crc; @@ -30,26 +50,22 @@ static void generate_crc64_table(void) for (j = 0; j < 8; j++) { if ((crc ^ c) & 0x8000000000000000ULL) - crc = (crc << 1) ^ CRC64_ECMA182_POLY; + crc = (crc << 1) ^ poly; else crc <<= 1; c <<= 1; } - crc64_table[i] = crc; + table[i] = crc; } } -static void print_crc64_table(void) +static void output_table(uint64_t table[256]) { int i; - printf("/* this file is generated - do not edit */\n\n"); - printf("#include <linux/types.h>\n"); - printf("#include <linux/cache.h>\n\n"); - printf("static const u64 ____cacheline_aligned crc64table[256] = {\n"); for (i = 0; i < 256; i++) { - printf("\t0x%016" PRIx64 "ULL", crc64_table[i]); + printf("\t0x%016" PRIx64 "ULL", table[i]); if (i & 0x1) printf(",\n"); else @@ -58,9 +74,22 @@ static void print_crc64_table(void) printf("};\n"); } +static void print_crc64_tables(void) +{ + printf("/* this file is generated - do not edit */\n\n"); + printf("#include <linux/types.h>\n"); + printf("#include <linux/cache.h>\n\n"); + printf("static const u64 ____cacheline_aligned crc64table[256] = {\n"); + output_table(crc64_table); + + printf("\nstatic const u64 ____cacheline_aligned crc64rocksofttable[256] = {\n"); + output_table(crc64_rocksoft_table); +} + int main(int argc, char *argv[]) { - generate_crc64_table(); - print_crc64_table(); + generate_crc64_table(crc64_table, CRC64_ECMA182_POLY); + generate_reflected_crc64_table(crc64_rocksoft_table, CRC64_ROCKSOFT_POLY); + print_crc64_tables(); return 0; } |