| /* crc32.c -- compute the CRC-32 of a data stream |
| * Copyright (C) 1995-2022 Mark Adler |
| * For conditions of distribution and use, see copyright notice in zlib.h |
| * |
| * This interleaved implementation of a CRC makes use of pipelined multiple |
| * arithmetic-logic units, commonly found in modern CPU cores. It is due to |
| * Kadatch and Jenkins (2010). See doc/crc-doc.1.0.pdf in this distribution. |
| */ |
| |
| /* @(#) $Id$ */ |
| |
| /* |
| Note on the use of DYNAMIC_CRC_TABLE: there is no mutex or semaphore |
| protection on the static variables used to control the first-use generation |
| of the crc tables. Therefore, if you #define DYNAMIC_CRC_TABLE, you should |
| first call get_crc_table() to initialize the tables before allowing more than |
| one thread to use crc32(). |
| |
| MAKECRCH can be #defined to write out crc32.h. A main() routine is also |
| produced, so that this one source file can be compiled to an executable. |
| */ |
| |
| #ifdef MAKECRCH |
| # include <stdio.h> |
| # ifndef DYNAMIC_CRC_TABLE |
| # define DYNAMIC_CRC_TABLE |
| # endif /* !DYNAMIC_CRC_TABLE */ |
| #endif /* MAKECRCH */ |
| |
| #include "zutil.h" /* for Z_U4, Z_U8, z_crc_t, and FAR definitions */ |
| |
| /* |
| A CRC of a message is computed on N braids of words in the message, where |
| each word consists of W bytes (4 or 8). If N is 3, for example, then three |
| running sparse CRCs are calculated respectively on each braid, at these |
| indices in the array of words: 0, 3, 6, ..., 1, 4, 7, ..., and 2, 5, 8, ... |
| This is done starting at a word boundary, and continues until as many blocks |
| of N * W bytes as are available have been processed. The results are combined |
| into a single CRC at the end. For this code, N must be in the range 1..6 and |
| W must be 4 or 8. The upper limit on N can be increased if desired by adding |
| more #if blocks, extending the patterns apparent in the code. In addition, |
| crc32.h would need to be regenerated, if the maximum N value is increased. |
| |
| N and W are chosen empirically by benchmarking the execution time on a given |
| processor. The choices for N and W below were based on testing on Intel Kaby |
| Lake i7, AMD Ryzen 7, ARM Cortex-A57, Sparc64-VII, PowerPC POWER9, and MIPS64 |
| Octeon II processors. The Intel, AMD, and ARM processors were all fastest |
| with N=5, W=8. The Sparc, PowerPC, and MIPS64 were all fastest at N=5, W=4. |
| They were all tested with either gcc or clang, all using the -O3 optimization |
| level. Your mileage may vary. |
| */ |
| |
| /* Define N */ |
| #ifdef Z_TESTN |
| # define N Z_TESTN |
| #else |
| # define N 5 |
| #endif |
| #if N < 1 || N > 6 |
| # error N must be in 1..6 |
| #endif |
| |
| /* |
| z_crc_t must be at least 32 bits. z_word_t must be at least as long as |
| z_crc_t. It is assumed here that z_word_t is either 32 bits or 64 bits, and |
| that bytes are eight bits. |
| */ |
| |
| /* |
| Define W and the associated z_word_t type. If W is not defined, then a |
| braided calculation is not used, and the associated tables and code are not |
| compiled. |
| */ |
| #ifdef Z_TESTW |
| # if Z_TESTW-1 != -1 |
| # define W Z_TESTW |
| # endif |
| #else |
| # ifdef MAKECRCH |
| # define W 8 /* required for MAKECRCH */ |
| # else |
| # if defined(__x86_64__) || defined(__aarch64__) |
| # define W 8 |
| # else |
| # define W 4 |
| # endif |
| # endif |
| #endif |
| #ifdef W |
| # if W == 8 && defined(Z_U8) |
| typedef Z_U8 z_word_t; |
| # elif defined(Z_U4) |
| # undef W |
| # define W 4 |
| typedef Z_U4 z_word_t; |
| # else |
| # undef W |
| # endif |
| #endif |
| |
| /* If available, use the ARM processor CRC32 instruction. */ |
| #if defined(__aarch64__) && defined(__ARM_FEATURE_CRC32) && W == 8 |
| # define ARMCRC32 |
| #endif |
| |
| #if defined(W) && (!defined(ARMCRC32) || defined(DYNAMIC_CRC_TABLE)) |
| /* |
| Swap the bytes in a z_word_t to convert between little and big endian. Any |
| self-respecting compiler will optimize this to a single machine byte-swap |
| instruction, if one is available. This assumes that word_t is either 32 bits |
| or 64 bits. |
| */ |
| local z_word_t byte_swap(z_word_t word) { |
| # if W == 8 |
| return |
| (word & 0xff00000000000000) >> 56 | |
| (word & 0xff000000000000) >> 40 | |
| (word & 0xff0000000000) >> 24 | |
| (word & 0xff00000000) >> 8 | |
| (word & 0xff000000) << 8 | |
| (word & 0xff0000) << 24 | |
| (word & 0xff00) << 40 | |
| (word & 0xff) << 56; |
| # else /* W == 4 */ |
| return |
| (word & 0xff000000) >> 24 | |
| (word & 0xff0000) >> 8 | |
| (word & 0xff00) << 8 | |
| (word & 0xff) << 24; |
| # endif |
| } |
| #endif |
| |
| #ifdef DYNAMIC_CRC_TABLE |
| /* ========================================================================= |
| * Table of powers of x for combining CRC-32s, filled in by make_crc_table() |
| * below. |
| */ |
| local z_crc_t FAR x2n_table[32]; |
| #else |
| /* ========================================================================= |
| * Tables for byte-wise and braided CRC-32 calculations, and a table of powers |
| * of x for combining CRC-32s, all made by make_crc_table(). |
| */ |
| # include "crc32.h" |
| #endif |
| |
| /* CRC polynomial. */ |
| #define POLY 0xedb88320 /* p(x) reflected, with x^32 implied */ |
| |
| /* |
| Return a(x) multiplied by b(x) modulo p(x), where p(x) is the CRC polynomial, |
| reflected. For speed, this requires that a not be zero. |
| */ |
| local z_crc_t multmodp(z_crc_t a, z_crc_t b) { |
| z_crc_t m, p; |
| |
| m = (z_crc_t)1 << 31; |
| p = 0; |
| for (;;) { |
| if (a & m) { |
| p ^= b; |
| if ((a & (m - 1)) == 0) |
| break; |
| } |
| m >>= 1; |
| b = b & 1 ? (b >> 1) ^ POLY : b >> 1; |
| } |
| return p; |
| } |
| |
| /* |
| Return x^(n * 2^k) modulo p(x). Requires that x2n_table[] has been |
| initialized. |
| */ |
| local z_crc_t x2nmodp(z_off64_t n, unsigned k) { |
| z_crc_t p; |
| |
| p = (z_crc_t)1 << 31; /* x^0 == 1 */ |
| while (n) { |
| if (n & 1) |
| p = multmodp(x2n_table[k & 31], p); |
| n >>= 1; |
| k++; |
| } |
| return p; |
| } |
| |
| #ifdef DYNAMIC_CRC_TABLE |
| /* ========================================================================= |
| * Build the tables for byte-wise and braided CRC-32 calculations, and a table |
| * of powers of x for combining CRC-32s. |
| */ |
| local z_crc_t FAR crc_table[256]; |
| #ifdef W |
| local z_word_t FAR crc_big_table[256]; |
| local z_crc_t FAR crc_braid_table[W][256]; |
| local z_word_t FAR crc_braid_big_table[W][256]; |
| local void braid(z_crc_t [][256], z_word_t [][256], int, int); |
| #endif |
| #ifdef MAKECRCH |
| local void write_table(FILE *, const z_crc_t FAR *, int); |
| local void write_table32hi(FILE *, const z_word_t FAR *, int); |
| local void write_table64(FILE *, const z_word_t FAR *, int); |
| #endif /* MAKECRCH */ |
| |
| /* |
| Define a once() function depending on the availability of atomics. If this is |
| compiled with DYNAMIC_CRC_TABLE defined, and if CRCs will be computed in |
| multiple threads, and if atomics are not available, then get_crc_table() must |
| be called to initialize the tables and must return before any threads are |
| allowed to compute or combine CRCs. |
| */ |
| |
| /* Definition of once functionality. */ |
| typedef struct once_s once_t; |
| |
| /* Check for the availability of atomics. */ |
| #if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \ |
| !defined(__STDC_NO_ATOMICS__) |
| |
| #include <stdatomic.h> |
| |
| /* Structure for once(), which must be initialized with ONCE_INIT. */ |
| struct once_s { |
| atomic_flag begun; |
| atomic_int done; |
| }; |
| #define ONCE_INIT {ATOMIC_FLAG_INIT, 0} |
| |
| /* |
| Run the provided init() function exactly once, even if multiple threads |
| invoke once() at the same time. The state must be a once_t initialized with |
| ONCE_INIT. |
| */ |
| local void once(once_t *state, void (*init)(void)) { |
| if (!atomic_load(&state->done)) { |
| if (atomic_flag_test_and_set(&state->begun)) |
| while (!atomic_load(&state->done)) |
| ; |
| else { |
| init(); |
| atomic_store(&state->done, 1); |
| } |
| } |
| } |
| |
| #else /* no atomics */ |
| |
| /* Structure for once(), which must be initialized with ONCE_INIT. */ |
| struct once_s { |
| volatile int begun; |
| volatile int done; |
| }; |
| #define ONCE_INIT {0, 0} |
| |
| /* Test and set. Alas, not atomic, but tries to minimize the period of |
| vulnerability. */ |
| local int test_and_set(int volatile *flag) { |
| int was; |
| |
| was = *flag; |
| *flag = 1; |
| return was; |
| } |
| |
| /* Run the provided init() function once. This is not thread-safe. */ |
| local void once(once_t *state, void (*init)(void)) { |
| if (!state->done) { |
| if (test_and_set(&state->begun)) |
| while (!state->done) |
| ; |
| else { |
| init(); |
| state->done = 1; |
| } |
| } |
| } |
| |
| #endif |
| |
| /* State for once(). */ |
| local once_t made = ONCE_INIT; |
| |
| /* |
| Generate tables for a byte-wise 32-bit CRC calculation on the polynomial: |
| x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1. |
| |
| Polynomials over GF(2) are represented in binary, one bit per coefficient, |
| with the lowest powers in the most significant bit. Then adding polynomials |
| is just exclusive-or, and multiplying a polynomial by x is a right shift by |
| one. If we call the above polynomial p, and represent a byte as the |
| polynomial q, also with the lowest power in the most significant bit (so the |
| byte 0xb1 is the polynomial x^7+x^3+x^2+1), then the CRC is (q*x^32) mod p, |
| where a mod b means the remainder after dividing a by b. |
| |
| This calculation is done using the shift-register method of multiplying and |
| taking the remainder. The register is initialized to zero, and for each |
| incoming bit, x^32 is added mod p to the register if the bit is a one (where |
| x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by x |
| (which is shifting right by one and adding x^32 mod p if the bit shifted out |
| is a one). We start with the highest power (least significant bit) of q and |
| repeat for all eight bits of q. |
| |
| The table is simply the CRC of all possible eight bit values. This is all the |
| information needed to generate CRCs on data a byte at a time for all |
| combinations of CRC register values and incoming bytes. |
| */ |
| |
| local void make_crc_table(void) { |
| unsigned i, j, n; |
| z_crc_t p; |
| |
| /* initialize the CRC of bytes tables */ |
| for (i = 0; i < 256; i++) { |
| p = i; |
| for (j = 0; j < 8; j++) |
| p = p & 1 ? (p >> 1) ^ POLY : p >> 1; |
| crc_table[i] = p; |
| #ifdef W |
| crc_big_table[i] = byte_swap(p); |
| #endif |
| } |
| |
| /* initialize the x^2^n mod p(x) table */ |
| p = (z_crc_t)1 << 30; /* x^1 */ |
| x2n_table[0] = p; |
| for (n = 1; n < 32; n++) |
| x2n_table[n] = p = multmodp(p, p); |
| |
| #ifdef W |
| /* initialize the braiding tables -- needs x2n_table[] */ |
| braid(crc_braid_table, crc_braid_big_table, N, W); |
| #endif |
| |
| #ifdef MAKECRCH |
| { |
| /* |
| The crc32.h header file contains tables for both 32-bit and 64-bit |
| z_word_t's, and so requires a 64-bit type be available. In that case, |
| z_word_t must be defined to be 64-bits. This code then also generates |
| and writes out the tables for the case that z_word_t is 32 bits. |
| */ |
| #if !defined(W) || W != 8 |
| # error Need a 64-bit integer type in order to generate crc32.h. |
| #endif |
| FILE *out; |
| int k, n; |
| z_crc_t ltl[8][256]; |
| z_word_t big[8][256]; |
| |
| out = fopen("crc32.h", "w"); |
| if (out == NULL) return; |
| |
| /* write out little-endian CRC table to crc32.h */ |
| fprintf(out, |
| "/* crc32.h -- tables for rapid CRC calculation\n" |
| " * Generated automatically by crc32.c\n */\n" |
| "\n" |
| "local const z_crc_t FAR crc_table[] = {\n" |
| " "); |
| write_table(out, crc_table, 256); |
| fprintf(out, |
| "};\n"); |
| |
| /* write out big-endian CRC table for 64-bit z_word_t to crc32.h */ |
| fprintf(out, |
| "\n" |
| "#ifdef W\n" |
| "\n" |
| "#if W == 8\n" |
| "\n" |
| "local const z_word_t FAR crc_big_table[] = {\n" |
| " "); |
| write_table64(out, crc_big_table, 256); |
| fprintf(out, |
| "};\n"); |
| |
| /* write out big-endian CRC table for 32-bit z_word_t to crc32.h */ |
| fprintf(out, |
| "\n" |
| "#else /* W == 4 */\n" |
| "\n" |
| "local const z_word_t FAR crc_big_table[] = {\n" |
| " "); |
| write_table32hi(out, crc_big_table, 256); |
| fprintf(out, |
| "};\n" |
| "\n" |
| "#endif\n"); |
| |
| /* write out braid tables for each value of N */ |
| for (n = 1; n <= 6; n++) { |
| fprintf(out, |
| "\n" |
| "#if N == %d\n", n); |
| |
| /* compute braid tables for this N and 64-bit word_t */ |
| braid(ltl, big, n, 8); |
| |
| /* write out braid tables for 64-bit z_word_t to crc32.h */ |
| fprintf(out, |
| "\n" |
| "#if W == 8\n" |
| "\n" |
| "local const z_crc_t FAR crc_braid_table[][256] = {\n"); |
| for (k = 0; k < 8; k++) { |
| fprintf(out, " {"); |
| write_table(out, ltl[k], 256); |
| fprintf(out, "}%s", k < 7 ? ",\n" : ""); |
| } |
| fprintf(out, |
| "};\n" |
| "\n" |
| "local const z_word_t FAR crc_braid_big_table[][256] = {\n"); |
| for (k = 0; k < 8; k++) { |
| fprintf(out, " {"); |
| write_table64(out, big[k], 256); |
| fprintf(out, "}%s", k < 7 ? ",\n" : ""); |
| } |
| fprintf(out, |
| "};\n"); |
| |
| /* compute braid tables for this N and 32-bit word_t */ |
| braid(ltl, big, n, 4); |
| |
| /* write out braid tables for 32-bit z_word_t to crc32.h */ |
| fprintf(out, |
| "\n" |
| "#else /* W == 4 */\n" |
| "\n" |
| "local const z_crc_t FAR crc_braid_table[][256] = {\n"); |
| for (k = 0; k < 4; k++) { |
| fprintf(out, " {"); |
| write_table(out, ltl[k], 256); |
| fprintf(out, "}%s", k < 3 ? ",\n" : ""); |
| } |
| fprintf(out, |
| "};\n" |
| "\n" |
| "local const z_word_t FAR crc_braid_big_table[][256] = {\n"); |
| for (k = 0; k < 4; k++) { |
| fprintf(out, " {"); |
| write_table32hi(out, big[k], 256); |
| fprintf(out, "}%s", k < 3 ? ",\n" : ""); |
| } |
| fprintf(out, |
| "};\n" |
| "\n" |
| "#endif\n" |
| "\n" |
| "#endif\n"); |
| } |
| fprintf(out, |
| "\n" |
| "#endif\n"); |
| |
| /* write out zeros operator table to crc32.h */ |
| fprintf(out, |
| "\n" |
| "local const z_crc_t FAR x2n_table[] = {\n" |
| " "); |
| write_table(out, x2n_table, 32); |
| fprintf(out, |
| "};\n"); |
| fclose(out); |
| } |
| #endif /* MAKECRCH */ |
| } |
| |
| #ifdef MAKECRCH |
| |
| /* |
| Write the 32-bit values in table[0..k-1] to out, five per line in |
| hexadecimal separated by commas. |
| */ |
| local void write_table(FILE *out, const z_crc_t FAR *table, int k) { |
| int n; |
| |
| for (n = 0; n < k; n++) |
| fprintf(out, "%s0x%08lx%s", n == 0 || n % 5 ? "" : " ", |
| (unsigned long)(table[n]), |
| n == k - 1 ? "" : (n % 5 == 4 ? ",\n" : ", ")); |
| } |
| |
| /* |
| Write the high 32-bits of each value in table[0..k-1] to out, five per line |
| in hexadecimal separated by commas. |
| */ |
| local void write_table32hi(FILE *out, const z_word_t FAR *table, int k) { |
| int n; |
| |
| for (n = 0; n < k; n++) |
| fprintf(out, "%s0x%08lx%s", n == 0 || n % 5 ? "" : " ", |
| (unsigned long)(table[n] >> 32), |
| n == k - 1 ? "" : (n % 5 == 4 ? ",\n" : ", ")); |
| } |
| |
| /* |
| Write the 64-bit values in table[0..k-1] to out, three per line in |
| hexadecimal separated by commas. This assumes that if there is a 64-bit |
| type, then there is also a long long integer type, and it is at least 64 |
| bits. If not, then the type cast and format string can be adjusted |
| accordingly. |
| */ |
| local void write_table64(FILE *out, const z_word_t FAR *table, int k) { |
| int n; |
| |
| for (n = 0; n < k; n++) |
| fprintf(out, "%s0x%016llx%s", n == 0 || n % 3 ? "" : " ", |
| (unsigned long long)(table[n]), |
| n == k - 1 ? "" : (n % 3 == 2 ? ",\n" : ", ")); |
| } |
| |
| /* Actually do the deed. */ |
| int main(void) { |
| make_crc_table(); |
| return 0; |
| } |
| |
| #endif /* MAKECRCH */ |
| |
| #ifdef W |
| /* |
| Generate the little and big-endian braid tables for the given n and z_word_t |
| size w. Each array must have room for w blocks of 256 elements. |
| */ |
| local void braid(z_crc_t ltl[][256], z_word_t big[][256], int n, int w) { |
| int k; |
| z_crc_t i, p, q; |
| for (k = 0; k < w; k++) { |
| p = x2nmodp((n * w + 3 - k) << 3, 0); |
| ltl[k][0] = 0; |
| big[w - 1 - k][0] = 0; |
| for (i = 1; i < 256; i++) { |
| ltl[k][i] = q = multmodp(i << 24, p); |
| big[w - 1 - k][i] = byte_swap(q); |
| } |
| } |
| } |
| #endif |
| |
| #endif /* DYNAMIC_CRC_TABLE */ |
| |
| /* ========================================================================= |
| * This function can be used by asm versions of crc32(), and to force the |
| * generation of the CRC tables in a threaded application. |
| */ |
| const z_crc_t FAR * ZEXPORT get_crc_table(void) { |
| #ifdef DYNAMIC_CRC_TABLE |
| once(&made, make_crc_table); |
| #endif /* DYNAMIC_CRC_TABLE */ |
| return (const z_crc_t FAR *)crc_table; |
| } |
| |
| /* ========================================================================= |
| * Use ARM machine instructions if available. This will compute the CRC about |
| * ten times faster than the braided calculation. This code does not check for |
| * the presence of the CRC instruction at run time. __ARM_FEATURE_CRC32 will |
| * only be defined if the compilation specifies an ARM processor architecture |
| * that has the instructions. For example, compiling with -march=armv8.1-a or |
| * -march=armv8-a+crc, or -march=native if the compile machine has the crc32 |
| * instructions. |
| */ |
| #ifdef ARMCRC32 |
| |
| /* |
| Constants empirically determined to maximize speed. These values are from |
| measurements on a Cortex-A57. Your mileage may vary. |
| */ |
| #define Z_BATCH 3990 /* number of words in a batch */ |
| #define Z_BATCH_ZEROS 0xa10d3d0c /* computed from Z_BATCH = 3990 */ |
| #define Z_BATCH_MIN 800 /* fewest words in a final batch */ |
| |
| unsigned long ZEXPORT crc32_z(unsigned long crc, const unsigned char FAR *buf, |
| z_size_t len) { |
| z_crc_t val; |
| z_word_t crc1, crc2; |
| const z_word_t *word; |
| z_word_t val0, val1, val2; |
| z_size_t last, last2, i; |
| z_size_t num; |
| |
| /* Return initial CRC, if requested. */ |
| if (buf == Z_NULL) return 0; |
| |
| #ifdef DYNAMIC_CRC_TABLE |
| once(&made, make_crc_table); |
| #endif /* DYNAMIC_CRC_TABLE */ |
| |
| /* Pre-condition the CRC */ |
| crc = (~crc) & 0xffffffff; |
| |
| /* Compute the CRC up to a word boundary. */ |
| while (len && ((z_size_t)buf & 7) != 0) { |
| len--; |
| val = *buf++; |
| __asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val)); |
| } |
| |
| /* Prepare to compute the CRC on full 64-bit words word[0..num-1]. */ |
| word = (z_word_t const *)buf; |
| num = len >> 3; |
| len &= 7; |
| |
| /* Do three interleaved CRCs to realize the throughput of one crc32x |
| instruction per cycle. Each CRC is calculated on Z_BATCH words. The |
| three CRCs are combined into a single CRC after each set of batches. */ |
| while (num >= 3 * Z_BATCH) { |
| crc1 = 0; |
| crc2 = 0; |
| for (i = 0; i < Z_BATCH; i++) { |
| val0 = word[i]; |
| val1 = word[i + Z_BATCH]; |
| val2 = word[i + 2 * Z_BATCH]; |
| __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0)); |
| __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1)); |
| __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2)); |
| } |
| word += 3 * Z_BATCH; |
| num -= 3 * Z_BATCH; |
| crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc1; |
| crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc2; |
| } |
| |
| /* Do one last smaller batch with the remaining words, if there are enough |
| to pay for the combination of CRCs. */ |
| last = num / 3; |
| if (last >= Z_BATCH_MIN) { |
| last2 = last << 1; |
| crc1 = 0; |
| crc2 = 0; |
| for (i = 0; i < last; i++) { |
| val0 = word[i]; |
| val1 = word[i + last]; |
| val2 = word[i + last2]; |
| __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0)); |
| __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1)); |
| __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2)); |
| } |
| word += 3 * last; |
| num -= 3 * last; |
| val = x2nmodp(last, 6); |
| crc = multmodp(val, crc) ^ crc1; |
| crc = multmodp(val, crc) ^ crc2; |
| } |
| |
| /* Compute the CRC on any remaining words. */ |
| for (i = 0; i < num; i++) { |
| val0 = word[i]; |
| __asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0)); |
| } |
| word += num; |
| |
| /* Complete the CRC on any remaining bytes. */ |
| buf = (const unsigned char FAR *)word; |
| while (len) { |
| len--; |
| val = *buf++; |
| __asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val)); |
| } |
| |
| /* Return the CRC, post-conditioned. */ |
| return crc ^ 0xffffffff; |
| } |
| |
| #else |
| |
| #ifdef W |
| |
| /* |
| Return the CRC of the W bytes in the word_t data, taking the |
| least-significant byte of the word as the first byte of data, without any pre |
| or post conditioning. This is used to combine the CRCs of each braid. |
| */ |
| local z_crc_t crc_word(z_word_t data) { |
| int k; |
| for (k = 0; k < W; k++) |
| data = (data >> 8) ^ crc_table[data & 0xff]; |
| return (z_crc_t)data; |
| } |
| |
| local z_word_t crc_word_big(z_word_t data) { |
| int k; |
| for (k = 0; k < W; k++) |
| data = (data << 8) ^ |
| crc_big_table[(data >> ((W - 1) << 3)) & 0xff]; |
| return data; |
| } |
| |
| #endif |
| |
| /* ========================================================================= */ |
| unsigned long ZEXPORT crc32_z(unsigned long crc, const unsigned char FAR *buf, |
| z_size_t len) { |
| /* Return initial CRC, if requested. */ |
| if (buf == Z_NULL) return 0; |
| |
| #ifdef DYNAMIC_CRC_TABLE |
| once(&made, make_crc_table); |
| #endif /* DYNAMIC_CRC_TABLE */ |
| |
| /* Pre-condition the CRC */ |
| crc = (~crc) & 0xffffffff; |
| |
| #ifdef W |
| |
| /* If provided enough bytes, do a braided CRC calculation. */ |
| if (len >= N * W + W - 1) { |
| z_size_t blks; |
| z_word_t const *words; |
| unsigned endian; |
| int k; |
| |
| /* Compute the CRC up to a z_word_t boundary. */ |
| while (len && ((z_size_t)buf & (W - 1)) != 0) { |
| len--; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| } |
| |
| /* Compute the CRC on as many N z_word_t blocks as are available. */ |
| blks = len / (N * W); |
| len -= blks * N * W; |
| words = (z_word_t const *)buf; |
| |
| /* Do endian check at execution time instead of compile time, since ARM |
| processors can change the endianness at execution time. If the |
| compiler knows what the endianness will be, it can optimize out the |
| check and the unused branch. */ |
| endian = 1; |
| if (*(unsigned char *)&endian) { |
| /* Little endian. */ |
| |
| z_crc_t crc0; |
| z_word_t word0; |
| #if N > 1 |
| z_crc_t crc1; |
| z_word_t word1; |
| #if N > 2 |
| z_crc_t crc2; |
| z_word_t word2; |
| #if N > 3 |
| z_crc_t crc3; |
| z_word_t word3; |
| #if N > 4 |
| z_crc_t crc4; |
| z_word_t word4; |
| #if N > 5 |
| z_crc_t crc5; |
| z_word_t word5; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| |
| /* Initialize the CRC for each braid. */ |
| crc0 = crc; |
| #if N > 1 |
| crc1 = 0; |
| #if N > 2 |
| crc2 = 0; |
| #if N > 3 |
| crc3 = 0; |
| #if N > 4 |
| crc4 = 0; |
| #if N > 5 |
| crc5 = 0; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| |
| /* |
| Process the first blks-1 blocks, computing the CRCs on each braid |
| independently. |
| */ |
| while (--blks) { |
| /* Load the word for each braid into registers. */ |
| word0 = crc0 ^ words[0]; |
| #if N > 1 |
| word1 = crc1 ^ words[1]; |
| #if N > 2 |
| word2 = crc2 ^ words[2]; |
| #if N > 3 |
| word3 = crc3 ^ words[3]; |
| #if N > 4 |
| word4 = crc4 ^ words[4]; |
| #if N > 5 |
| word5 = crc5 ^ words[5]; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| words += N; |
| |
| /* Compute and update the CRC for each word. The loop should |
| get unrolled. */ |
| crc0 = crc_braid_table[0][word0 & 0xff]; |
| #if N > 1 |
| crc1 = crc_braid_table[0][word1 & 0xff]; |
| #if N > 2 |
| crc2 = crc_braid_table[0][word2 & 0xff]; |
| #if N > 3 |
| crc3 = crc_braid_table[0][word3 & 0xff]; |
| #if N > 4 |
| crc4 = crc_braid_table[0][word4 & 0xff]; |
| #if N > 5 |
| crc5 = crc_braid_table[0][word5 & 0xff]; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| for (k = 1; k < W; k++) { |
| crc0 ^= crc_braid_table[k][(word0 >> (k << 3)) & 0xff]; |
| #if N > 1 |
| crc1 ^= crc_braid_table[k][(word1 >> (k << 3)) & 0xff]; |
| #if N > 2 |
| crc2 ^= crc_braid_table[k][(word2 >> (k << 3)) & 0xff]; |
| #if N > 3 |
| crc3 ^= crc_braid_table[k][(word3 >> (k << 3)) & 0xff]; |
| #if N > 4 |
| crc4 ^= crc_braid_table[k][(word4 >> (k << 3)) & 0xff]; |
| #if N > 5 |
| crc5 ^= crc_braid_table[k][(word5 >> (k << 3)) & 0xff]; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| } |
| } |
| |
| /* |
| Process the last block, combining the CRCs of the N braids at the |
| same time. |
| */ |
| crc = crc_word(crc0 ^ words[0]); |
| #if N > 1 |
| crc = crc_word(crc1 ^ words[1] ^ crc); |
| #if N > 2 |
| crc = crc_word(crc2 ^ words[2] ^ crc); |
| #if N > 3 |
| crc = crc_word(crc3 ^ words[3] ^ crc); |
| #if N > 4 |
| crc = crc_word(crc4 ^ words[4] ^ crc); |
| #if N > 5 |
| crc = crc_word(crc5 ^ words[5] ^ crc); |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| words += N; |
| } |
| else { |
| /* Big endian. */ |
| |
| z_word_t crc0, word0, comb; |
| #if N > 1 |
| z_word_t crc1, word1; |
| #if N > 2 |
| z_word_t crc2, word2; |
| #if N > 3 |
| z_word_t crc3, word3; |
| #if N > 4 |
| z_word_t crc4, word4; |
| #if N > 5 |
| z_word_t crc5, word5; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| |
| /* Initialize the CRC for each braid. */ |
| crc0 = byte_swap(crc); |
| #if N > 1 |
| crc1 = 0; |
| #if N > 2 |
| crc2 = 0; |
| #if N > 3 |
| crc3 = 0; |
| #if N > 4 |
| crc4 = 0; |
| #if N > 5 |
| crc5 = 0; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| |
| /* |
| Process the first blks-1 blocks, computing the CRCs on each braid |
| independently. |
| */ |
| while (--blks) { |
| /* Load the word for each braid into registers. */ |
| word0 = crc0 ^ words[0]; |
| #if N > 1 |
| word1 = crc1 ^ words[1]; |
| #if N > 2 |
| word2 = crc2 ^ words[2]; |
| #if N > 3 |
| word3 = crc3 ^ words[3]; |
| #if N > 4 |
| word4 = crc4 ^ words[4]; |
| #if N > 5 |
| word5 = crc5 ^ words[5]; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| words += N; |
| |
| /* Compute and update the CRC for each word. The loop should |
| get unrolled. */ |
| crc0 = crc_braid_big_table[0][word0 & 0xff]; |
| #if N > 1 |
| crc1 = crc_braid_big_table[0][word1 & 0xff]; |
| #if N > 2 |
| crc2 = crc_braid_big_table[0][word2 & 0xff]; |
| #if N > 3 |
| crc3 = crc_braid_big_table[0][word3 & 0xff]; |
| #if N > 4 |
| crc4 = crc_braid_big_table[0][word4 & 0xff]; |
| #if N > 5 |
| crc5 = crc_braid_big_table[0][word5 & 0xff]; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| for (k = 1; k < W; k++) { |
| crc0 ^= crc_braid_big_table[k][(word0 >> (k << 3)) & 0xff]; |
| #if N > 1 |
| crc1 ^= crc_braid_big_table[k][(word1 >> (k << 3)) & 0xff]; |
| #if N > 2 |
| crc2 ^= crc_braid_big_table[k][(word2 >> (k << 3)) & 0xff]; |
| #if N > 3 |
| crc3 ^= crc_braid_big_table[k][(word3 >> (k << 3)) & 0xff]; |
| #if N > 4 |
| crc4 ^= crc_braid_big_table[k][(word4 >> (k << 3)) & 0xff]; |
| #if N > 5 |
| crc5 ^= crc_braid_big_table[k][(word5 >> (k << 3)) & 0xff]; |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| } |
| } |
| |
| /* |
| Process the last block, combining the CRCs of the N braids at the |
| same time. |
| */ |
| comb = crc_word_big(crc0 ^ words[0]); |
| #if N > 1 |
| comb = crc_word_big(crc1 ^ words[1] ^ comb); |
| #if N > 2 |
| comb = crc_word_big(crc2 ^ words[2] ^ comb); |
| #if N > 3 |
| comb = crc_word_big(crc3 ^ words[3] ^ comb); |
| #if N > 4 |
| comb = crc_word_big(crc4 ^ words[4] ^ comb); |
| #if N > 5 |
| comb = crc_word_big(crc5 ^ words[5] ^ comb); |
| #endif |
| #endif |
| #endif |
| #endif |
| #endif |
| words += N; |
| crc = byte_swap(comb); |
| } |
| |
| /* |
| Update the pointer to the remaining bytes to process. |
| */ |
| buf = (unsigned char const *)words; |
| } |
| |
| #endif /* W */ |
| |
| /* Complete the computation of the CRC on any remaining bytes. */ |
| while (len >= 8) { |
| len -= 8; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| } |
| while (len) { |
| len--; |
| crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; |
| } |
| |
| /* Return the CRC, post-conditioned. */ |
| return crc ^ 0xffffffff; |
| } |
| |
| #endif |
| |
| /* ========================================================================= */ |
| unsigned long ZEXPORT crc32(unsigned long crc, const unsigned char FAR *buf, |
| uInt len) { |
| return crc32_z(crc, buf, len); |
| } |
| |
| /* ========================================================================= */ |
| uLong ZEXPORT crc32_combine64(uLong crc1, uLong crc2, z_off64_t len2) { |
| #ifdef DYNAMIC_CRC_TABLE |
| once(&made, make_crc_table); |
| #endif /* DYNAMIC_CRC_TABLE */ |
| return multmodp(x2nmodp(len2, 3), crc1) ^ (crc2 & 0xffffffff); |
| } |
| |
| /* ========================================================================= */ |
| uLong ZEXPORT crc32_combine(uLong crc1, uLong crc2, z_off_t len2) { |
| return crc32_combine64(crc1, crc2, (z_off64_t)len2); |
| } |
| |
| /* ========================================================================= */ |
| uLong ZEXPORT crc32_combine_gen64(z_off64_t len2) { |
| #ifdef DYNAMIC_CRC_TABLE |
| once(&made, make_crc_table); |
| #endif /* DYNAMIC_CRC_TABLE */ |
| return x2nmodp(len2, 3); |
| } |
| |
| /* ========================================================================= */ |
| uLong ZEXPORT crc32_combine_gen(z_off_t len2) { |
| return crc32_combine_gen64((z_off64_t)len2); |
| } |
| |
| /* ========================================================================= */ |
| uLong ZEXPORT crc32_combine_op(uLong crc1, uLong crc2, uLong op) { |
| return multmodp(op, crc1) ^ (crc2 & 0xffffffff); |
| } |
