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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /lib/gen_crc32table.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/gen_crc32table.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c new file mode 100644 index 0000000000..f755b997b9 --- /dev/null +++ b/lib/gen_crc32table.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <stdio.h> +#include "../include/linux/crc32poly.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_ROWS (CRC_LE_BITS/8) +# define LE_TABLE_SIZE 256 +#else +# define LE_TABLE_ROWS 1 +# define LE_TABLE_SIZE (1 << CRC_LE_BITS) +#endif + +#if CRC_BE_BITS > 8 +# define BE_TABLE_ROWS (CRC_BE_BITS/8) +# define BE_TABLE_SIZE 256 +#else +# define BE_TABLE_ROWS 1 +# define BE_TABLE_SIZE (1 << CRC_BE_BITS) +#endif + +static uint32_t crc32table_le[LE_TABLE_ROWS][256]; +static uint32_t crc32table_be[BE_TABLE_ROWS][256]; +static uint32_t crc32ctable_le[LE_TABLE_ROWS][256]; + +/** + * crc32init_le() - allocate and initialize LE table data + * + * crc is the crc of the byte i; other entries are filled in based on the + * fact that crctable[i^j] = crctable[i] ^ crctable[j]. + * + */ +static void crc32init_le_generic(const uint32_t polynomial, + uint32_t (*tab)[256]) +{ + unsigned i, j; + uint32_t crc = 1; + + tab[0][0] = 0; + + for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) { + crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0); + for (j = 0; j < LE_TABLE_SIZE; j += 2 * i) + tab[0][i + j] = crc ^ tab[0][j]; + } + for (i = 0; i < LE_TABLE_SIZE; i++) { + crc = tab[0][i]; + for (j = 1; j < LE_TABLE_ROWS; j++) { + crc = tab[0][crc & 0xff] ^ (crc >> 8); + tab[j][i] = crc; + } + } +} + +static void crc32init_le(void) +{ + crc32init_le_generic(CRC32_POLY_LE, crc32table_le); +} + +static void crc32cinit_le(void) +{ + crc32init_le_generic(CRC32C_POLY_LE, crc32ctable_le); +} + +/** + * crc32init_be() - allocate and initialize BE table data + */ +static void crc32init_be(void) +{ + unsigned i, j; + uint32_t crc = 0x80000000; + + crc32table_be[0][0] = 0; + + for (i = 1; i < BE_TABLE_SIZE; i <<= 1) { + crc = (crc << 1) ^ ((crc & 0x80000000) ? CRC32_POLY_BE : 0); + for (j = 0; j < i; 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 < 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 rows, int len, char *trans) +{ + int i, j; + + for (j = 0 ; j < rows; 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]); + } +} + +int main(int argc, char** argv) +{ + printf("/* this file is generated - do not edit */\n\n"); + + if (CRC_LE_BITS > 1) { + crc32init_le(); + 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 ____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"); + } + if (CRC_LE_BITS > 1) { + crc32cinit_le(); + printf("static const u32 ____cacheline_aligned " + "crc32ctable_le[%d][%d] = {", + LE_TABLE_ROWS, LE_TABLE_SIZE); + output_table(crc32ctable_le, LE_TABLE_ROWS, + LE_TABLE_SIZE, "tole"); + printf("};\n"); + } + + return 0; +} |