diff options
| -rw-r--r-- | lib/crc32.c | 24 | ||||
| -rw-r--r-- | lib/gen_crc32table.c | 47 |
2 files changed, 47 insertions, 24 deletions
diff --git a/lib/crc32.c b/lib/crc32.c index bc5b936..4855995 100644 --- a/lib/crc32.c +++ b/lib/crc32.c @@ -48,12 +48,20 @@ MODULE_LICENSE("GPL"); #if CRC_LE_BITS == 8 || CRC_BE_BITS == 8 static inline u32 -crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 *tab) +crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 (*tab)[256]) { # ifdef __LITTLE_ENDIAN -# define DO_CRC(x) crc = tab[(crc ^ (x)) & 255 ] ^ (crc >> 8) +# define DO_CRC(x) crc = tab[0][(crc ^ (x)) & 255] ^ (crc >> 8) +# define DO_CRC4 crc = tab[3][(crc) & 255] ^ \ + tab[2][(crc >> 8) & 255] ^ \ + tab[1][(crc >> 16) & 255] ^ \ + tab[0][(crc >> 24) & 255] # else -# define DO_CRC(x) crc = tab[((crc >> 24) ^ (x)) & 255] ^ (crc << 8) +# define DO_CRC(x) crc = tab[0][((crc >> 24) ^ (x)) & 255] ^ (crc << 8) +# define DO_CRC4 crc = tab[0][(crc) & 255] ^ \ + tab[1][(crc >> 8) & 255] ^ \ + tab[2][(crc >> 16) & 255] ^ \ + tab[3][(crc >> 24) & 255] # endif const u32 *b; size_t rem_len; @@ -70,10 +78,7 @@ crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 *tab) b = (const u32 *)buf; for (--b; len; --len) { crc ^= *++b; /* use pre increment for speed */ - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); + DO_CRC4; } len = rem_len; /* And the last few bytes */ @@ -85,6 +90,7 @@ crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 *tab) } return crc; #undef DO_CRC +#undef DO_CRC4 } #endif /** @@ -117,7 +123,7 @@ u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) { # if CRC_LE_BITS == 8 - const u32 *tab = crc32table_le; + const u32 (*tab)[] = crc32table_le; crc = __cpu_to_le32(crc); crc = crc32_body(crc, p, len, tab); @@ -174,7 +180,7 @@ u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) { # if CRC_BE_BITS == 8 - const u32 *tab = crc32table_be; + const u32 (*tab)[] = crc32table_be; crc = __cpu_to_be32(crc); crc = crc32_body(crc, p, len, tab); diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c index bea5d97..85d0e41 100644 --- a/lib/gen_crc32table.c +++ b/lib/gen_crc32table.c @@ -7,8 +7,8 @@ #define LE_TABLE_SIZE (1 << CRC_LE_BITS) #define BE_TABLE_SIZE (1 << CRC_BE_BITS) -static uint32_t crc32table_le[LE_TABLE_SIZE]; -static uint32_t crc32table_be[BE_TABLE_SIZE]; +static uint32_t crc32table_le[4][LE_TABLE_SIZE]; +static uint32_t crc32table_be[4][BE_TABLE_SIZE]; /** * crc32init_le() - allocate and initialize LE table data @@ -22,12 +22,19 @@ static void crc32init_le(void) unsigned i, j; uint32_t crc = 1; - crc32table_le[0] = 0; + crc32table_le[0][0] = 0; for (i = 1 << (CRC_LE_BITS - 1); i; i >>= 1) { crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0); for (j = 0; j < LE_TABLE_SIZE; j += 2 * i) - crc32table_le[i + j] = crc ^ crc32table_le[j]; + crc32table_le[0][i + j] = crc ^ crc32table_le[0][j]; + } + for (i = 0; i < LE_TABLE_SIZE; i++) { + crc = crc32table_le[0][i]; + for (j = 1; j < 4; j++) { + crc = crc32table_le[0][crc & 0xff] ^ (crc >> 8); + crc32table_le[j][i] = crc; + } } } @@ -39,25 +46,35 @@ static void crc32init_be(void) unsigned i, j; uint32_t crc = 0x80000000; - crc32table_be[0] = 0; + crc32table_be[0][0] = 0; for (i = 1; i < BE_TABLE_SIZE; i <<= 1) { crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0); for (j = 0; j < i; j++) - crc32table_be[i + j] = crc ^ crc32table_be[j]; + crc32table_be[0][i + j] = crc ^ crc32table_be[0][j]; + } + for (i = 0; i < BE_TABLE_SIZE; i++) { + crc = crc32table_be[0][i]; + for (j = 1; j < 4; j++) { + crc = crc32table_be[0][(crc >> 24) & 0xff] ^ (crc << 8); + crc32table_be[j][i] = crc; + } } } -static void output_table(uint32_t table[], int len, char *trans) +static void output_table(uint32_t table[4][256], int len, char *trans) { - int i; + int i, j; - for (i = 0; i < len - 1; i++) { - if (i % ENTRIES_PER_LINE == 0) - printf("\n"); - printf("%s(0x%8.8xL), ", trans, table[i]); + for (j = 0 ; j < 4; j++) { + printf("{"); + for (i = 0; i < len - 1; i++) { + if (i % ENTRIES_PER_LINE == 0) + printf("\n"); + printf("%s(0x%8.8xL), ", trans, table[j][i]); + } + printf("%s(0x%8.8xL)},\n", trans, table[j][len - 1]); } - printf("%s(0x%8.8xL)\n", trans, table[len - 1]); } int main(int argc, char** argv) @@ -66,14 +83,14 @@ int main(int argc, char** argv) if (CRC_LE_BITS > 1) { crc32init_le(); - printf("static const u32 crc32table_le[] = {"); + printf("static const u32 crc32table_le[4][256] = {"); output_table(crc32table_le, LE_TABLE_SIZE, "tole"); printf("};\n"); } if (CRC_BE_BITS > 1) { crc32init_be(); - printf("static const u32 crc32table_be[] = {"); + printf("static const u32 crc32table_be[4][256] = {"); output_table(crc32table_be, BE_TABLE_SIZE, "tobe"); printf("};\n"); } |
