Kyungmin Park | 1d8dca6 | 2008-11-19 16:23:06 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Oct 15, 2000 Matt Domsch <Matt_Domsch@dell.com> |
| 3 | * Nicer crc32 functions/docs submitted by linux@horizon.com. Thanks! |
| 4 | * Code was from the public domain, copyright abandoned. Code was |
| 5 | * subsequently included in the kernel, thus was re-licensed under the |
| 6 | * GNU GPL v2. |
| 7 | * |
| 8 | * Oct 12, 2000 Matt Domsch <Matt_Domsch@dell.com> |
| 9 | * Same crc32 function was used in 5 other places in the kernel. |
| 10 | * I made one version, and deleted the others. |
| 11 | * There are various incantations of crc32(). Some use a seed of 0 or ~0. |
| 12 | * Some xor at the end with ~0. The generic crc32() function takes |
| 13 | * seed as an argument, and doesn't xor at the end. Then individual |
| 14 | * users can do whatever they need. |
| 15 | * drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0. |
| 16 | * fs/jffs2 uses seed 0, doesn't xor with ~0. |
| 17 | * fs/partitions/efi.c uses seed ~0, xor's with ~0. |
| 18 | * |
| 19 | * This source code is licensed under the GNU General Public License, |
| 20 | * Version 2. See the file COPYING for more details. |
| 21 | */ |
| 22 | |
| 23 | #ifdef UBI_LINUX |
| 24 | #include <linux/crc32.h> |
| 25 | #include <linux/kernel.h> |
| 26 | #include <linux/module.h> |
| 27 | #include <linux/compiler.h> |
| 28 | #endif |
| 29 | #include <linux/types.h> |
| 30 | |
| 31 | #include <asm/byteorder.h> |
| 32 | |
| 33 | #ifdef UBI_LINUX |
| 34 | #include <linux/slab.h> |
| 35 | #include <linux/init.h> |
| 36 | #include <asm/atomic.h> |
| 37 | #endif |
| 38 | #include "crc32defs.h" |
| 39 | #define CRC_LE_BITS 8 |
| 40 | |
| 41 | # define __force |
| 42 | #ifndef __constant_cpu_to_le32 |
| 43 | #define __constant_cpu_to_le32(x) ((__force __le32)(__u32)(x)) |
| 44 | #endif |
| 45 | #ifndef __constant_le32_to_cpu |
| 46 | #define __constant_le32_to_cpu(x) ((__force __u32)(__le32)(x)) |
| 47 | #endif |
| 48 | |
| 49 | #if CRC_LE_BITS == 8 |
| 50 | #define tole(x) __constant_cpu_to_le32(x) |
| 51 | #define tobe(x) __constant_cpu_to_be32(x) |
| 52 | #else |
| 53 | #define tole(x) (x) |
| 54 | #define tobe(x) (x) |
| 55 | #endif |
| 56 | #include "crc32table.h" |
| 57 | #ifdef UBI_LINUX |
| 58 | MODULE_AUTHOR("Matt Domsch <Matt_Domsch@dell.com>"); |
| 59 | MODULE_DESCRIPTION("Ethernet CRC32 calculations"); |
| 60 | MODULE_LICENSE("GPL"); |
| 61 | #endif |
| 62 | /** |
| 63 | * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32 |
| 64 | * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for |
| 65 | * other uses, or the previous crc32 value if computing incrementally. |
| 66 | * @p: pointer to buffer over which CRC is run |
| 67 | * @len: length of buffer @p |
| 68 | */ |
| 69 | u32 crc32_le(u32 crc, unsigned char const *p, size_t len); |
| 70 | |
| 71 | #if CRC_LE_BITS == 1 |
| 72 | /* |
| 73 | * In fact, the table-based code will work in this case, but it can be |
| 74 | * simplified by inlining the table in ?: form. |
| 75 | */ |
| 76 | |
| 77 | u32 crc32_le(u32 crc, unsigned char const *p, size_t len) |
| 78 | { |
| 79 | int i; |
| 80 | while (len--) { |
| 81 | crc ^= *p++; |
| 82 | for (i = 0; i < 8; i++) |
| 83 | crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0); |
| 84 | } |
| 85 | return crc; |
| 86 | } |
| 87 | #else /* Table-based approach */ |
| 88 | |
| 89 | u32 crc32_le(u32 crc, unsigned char const *p, size_t len) |
| 90 | { |
| 91 | # if CRC_LE_BITS == 8 |
| 92 | const u32 *b =(u32 *)p; |
| 93 | const u32 *tab = crc32table_le; |
| 94 | |
| 95 | # ifdef __LITTLE_ENDIAN |
| 96 | # define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8) |
| 97 | # else |
| 98 | # define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8) |
| 99 | # endif |
Wolfgang Denk | 55334c7 | 2008-12-16 01:02:17 +0100 | [diff] [blame] | 100 | /* printf("Crc32_le crc=%x\n",crc); */ |
Kyungmin Park | 1d8dca6 | 2008-11-19 16:23:06 +0100 | [diff] [blame] | 101 | crc = __cpu_to_le32(crc); |
| 102 | /* Align it */ |
| 103 | if((((long)b)&3 && len)){ |
| 104 | do { |
| 105 | u8 *p = (u8 *)b; |
| 106 | DO_CRC(*p++); |
| 107 | b = (void *)p; |
| 108 | } while ((--len) && ((long)b)&3 ); |
| 109 | } |
| 110 | if((len >= 4)){ |
| 111 | /* load data 32 bits wide, xor data 32 bits wide. */ |
| 112 | size_t save_len = len & 3; |
| 113 | len = len >> 2; |
| 114 | --b; /* use pre increment below(*++b) for speed */ |
| 115 | do { |
| 116 | crc ^= *++b; |
| 117 | DO_CRC(0); |
| 118 | DO_CRC(0); |
| 119 | DO_CRC(0); |
| 120 | DO_CRC(0); |
| 121 | } while (--len); |
| 122 | b++; /* point to next byte(s) */ |
| 123 | len = save_len; |
| 124 | } |
| 125 | /* And the last few bytes */ |
| 126 | if(len){ |
| 127 | do { |
| 128 | u8 *p = (u8 *)b; |
| 129 | DO_CRC(*p++); |
| 130 | b = (void *)p; |
| 131 | } while (--len); |
| 132 | } |
| 133 | |
| 134 | return __le32_to_cpu(crc); |
| 135 | #undef ENDIAN_SHIFT |
| 136 | #undef DO_CRC |
| 137 | |
| 138 | # elif CRC_LE_BITS == 4 |
| 139 | while (len--) { |
| 140 | crc ^= *p++; |
| 141 | crc = (crc >> 4) ^ crc32table_le[crc & 15]; |
| 142 | crc = (crc >> 4) ^ crc32table_le[crc & 15]; |
| 143 | } |
| 144 | return crc; |
| 145 | # elif CRC_LE_BITS == 2 |
| 146 | while (len--) { |
| 147 | crc ^= *p++; |
| 148 | crc = (crc >> 2) ^ crc32table_le[crc & 3]; |
| 149 | crc = (crc >> 2) ^ crc32table_le[crc & 3]; |
| 150 | crc = (crc >> 2) ^ crc32table_le[crc & 3]; |
| 151 | crc = (crc >> 2) ^ crc32table_le[crc & 3]; |
| 152 | } |
| 153 | return crc; |
| 154 | # endif |
| 155 | } |
| 156 | #endif |
| 157 | #ifdef UBI_LINUX |
| 158 | /** |
| 159 | * crc32_be() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32 |
| 160 | * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for |
| 161 | * other uses, or the previous crc32 value if computing incrementally. |
| 162 | * @p: pointer to buffer over which CRC is run |
| 163 | * @len: length of buffer @p |
| 164 | */ |
| 165 | u32 __attribute_pure__ crc32_be(u32 crc, unsigned char const *p, size_t len); |
| 166 | |
| 167 | #if CRC_BE_BITS == 1 |
| 168 | /* |
| 169 | * In fact, the table-based code will work in this case, but it can be |
| 170 | * simplified by inlining the table in ?: form. |
| 171 | */ |
| 172 | |
| 173 | u32 __attribute_pure__ crc32_be(u32 crc, unsigned char const *p, size_t len) |
| 174 | { |
| 175 | int i; |
| 176 | while (len--) { |
| 177 | crc ^= *p++ << 24; |
| 178 | for (i = 0; i < 8; i++) |
| 179 | crc = |
| 180 | (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : |
| 181 | 0); |
| 182 | } |
| 183 | return crc; |
| 184 | } |
| 185 | |
| 186 | #else /* Table-based approach */ |
| 187 | u32 __attribute_pure__ crc32_be(u32 crc, unsigned char const *p, size_t len) |
| 188 | { |
| 189 | # if CRC_BE_BITS == 8 |
| 190 | const u32 *b =(u32 *)p; |
| 191 | const u32 *tab = crc32table_be; |
| 192 | |
| 193 | # ifdef __LITTLE_ENDIAN |
| 194 | # define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8) |
| 195 | # else |
| 196 | # define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8) |
| 197 | # endif |
| 198 | |
| 199 | crc = __cpu_to_be32(crc); |
| 200 | /* Align it */ |
| 201 | if(unlikely(((long)b)&3 && len)){ |
| 202 | do { |
| 203 | u8 *p = (u8 *)b; |
| 204 | DO_CRC(*p++); |
| 205 | b = (u32 *)p; |
| 206 | } while ((--len) && ((long)b)&3 ); |
| 207 | } |
| 208 | if(likely(len >= 4)){ |
| 209 | /* load data 32 bits wide, xor data 32 bits wide. */ |
| 210 | size_t save_len = len & 3; |
| 211 | len = len >> 2; |
| 212 | --b; /* use pre increment below(*++b) for speed */ |
| 213 | do { |
| 214 | crc ^= *++b; |
| 215 | DO_CRC(0); |
| 216 | DO_CRC(0); |
| 217 | DO_CRC(0); |
| 218 | DO_CRC(0); |
| 219 | } while (--len); |
| 220 | b++; /* point to next byte(s) */ |
| 221 | len = save_len; |
| 222 | } |
| 223 | /* And the last few bytes */ |
| 224 | if(len){ |
| 225 | do { |
| 226 | u8 *p = (u8 *)b; |
| 227 | DO_CRC(*p++); |
| 228 | b = (void *)p; |
| 229 | } while (--len); |
| 230 | } |
| 231 | return __be32_to_cpu(crc); |
| 232 | #undef ENDIAN_SHIFT |
| 233 | #undef DO_CRC |
| 234 | |
| 235 | # elif CRC_BE_BITS == 4 |
| 236 | while (len--) { |
| 237 | crc ^= *p++ << 24; |
| 238 | crc = (crc << 4) ^ crc32table_be[crc >> 28]; |
| 239 | crc = (crc << 4) ^ crc32table_be[crc >> 28]; |
| 240 | } |
| 241 | return crc; |
| 242 | # elif CRC_BE_BITS == 2 |
| 243 | while (len--) { |
| 244 | crc ^= *p++ << 24; |
| 245 | crc = (crc << 2) ^ crc32table_be[crc >> 30]; |
| 246 | crc = (crc << 2) ^ crc32table_be[crc >> 30]; |
| 247 | crc = (crc << 2) ^ crc32table_be[crc >> 30]; |
| 248 | crc = (crc << 2) ^ crc32table_be[crc >> 30]; |
| 249 | } |
| 250 | return crc; |
| 251 | # endif |
| 252 | } |
| 253 | #endif |
| 254 | |
| 255 | EXPORT_SYMBOL(crc32_le); |
| 256 | EXPORT_SYMBOL(crc32_be); |
| 257 | #endif |
| 258 | /* |
| 259 | * A brief CRC tutorial. |
| 260 | * |
| 261 | * A CRC is a long-division remainder. You add the CRC to the message, |
| 262 | * and the whole thing (message+CRC) is a multiple of the given |
| 263 | * CRC polynomial. To check the CRC, you can either check that the |
| 264 | * CRC matches the recomputed value, *or* you can check that the |
| 265 | * remainder computed on the message+CRC is 0. This latter approach |
| 266 | * is used by a lot of hardware implementations, and is why so many |
| 267 | * protocols put the end-of-frame flag after the CRC. |
| 268 | * |
| 269 | * It's actually the same long division you learned in school, except that |
| 270 | * - We're working in binary, so the digits are only 0 and 1, and |
| 271 | * - When dividing polynomials, there are no carries. Rather than add and |
| 272 | * subtract, we just xor. Thus, we tend to get a bit sloppy about |
| 273 | * the difference between adding and subtracting. |
| 274 | * |
| 275 | * A 32-bit CRC polynomial is actually 33 bits long. But since it's |
| 276 | * 33 bits long, bit 32 is always going to be set, so usually the CRC |
| 277 | * is written in hex with the most significant bit omitted. (If you're |
| 278 | * familiar with the IEEE 754 floating-point format, it's the same idea.) |
| 279 | * |
| 280 | * Note that a CRC is computed over a string of *bits*, so you have |
| 281 | * to decide on the endianness of the bits within each byte. To get |
| 282 | * the best error-detecting properties, this should correspond to the |
| 283 | * order they're actually sent. For example, standard RS-232 serial is |
| 284 | * little-endian; the most significant bit (sometimes used for parity) |
| 285 | * is sent last. And when appending a CRC word to a message, you should |
| 286 | * do it in the right order, matching the endianness. |
| 287 | * |
| 288 | * Just like with ordinary division, the remainder is always smaller than |
| 289 | * the divisor (the CRC polynomial) you're dividing by. Each step of the |
| 290 | * division, you take one more digit (bit) of the dividend and append it |
| 291 | * to the current remainder. Then you figure out the appropriate multiple |
| 292 | * of the divisor to subtract to being the remainder back into range. |
| 293 | * In binary, it's easy - it has to be either 0 or 1, and to make the |
| 294 | * XOR cancel, it's just a copy of bit 32 of the remainder. |
| 295 | * |
| 296 | * When computing a CRC, we don't care about the quotient, so we can |
| 297 | * throw the quotient bit away, but subtract the appropriate multiple of |
| 298 | * the polynomial from the remainder and we're back to where we started, |
| 299 | * ready to process the next bit. |
| 300 | * |
| 301 | * A big-endian CRC written this way would be coded like: |
| 302 | * for (i = 0; i < input_bits; i++) { |
| 303 | * multiple = remainder & 0x80000000 ? CRCPOLY : 0; |
| 304 | * remainder = (remainder << 1 | next_input_bit()) ^ multiple; |
| 305 | * } |
| 306 | * Notice how, to get at bit 32 of the shifted remainder, we look |
| 307 | * at bit 31 of the remainder *before* shifting it. |
| 308 | * |
| 309 | * But also notice how the next_input_bit() bits we're shifting into |
| 310 | * the remainder don't actually affect any decision-making until |
| 311 | * 32 bits later. Thus, the first 32 cycles of this are pretty boring. |
| 312 | * Also, to add the CRC to a message, we need a 32-bit-long hole for it at |
| 313 | * the end, so we have to add 32 extra cycles shifting in zeros at the |
| 314 | * end of every message, |
| 315 | * |
| 316 | * So the standard trick is to rearrage merging in the next_input_bit() |
| 317 | * until the moment it's needed. Then the first 32 cycles can be precomputed, |
| 318 | * and merging in the final 32 zero bits to make room for the CRC can be |
| 319 | * skipped entirely. |
| 320 | * This changes the code to: |
| 321 | * for (i = 0; i < input_bits; i++) { |
| 322 | * remainder ^= next_input_bit() << 31; |
| 323 | * multiple = (remainder & 0x80000000) ? CRCPOLY : 0; |
| 324 | * remainder = (remainder << 1) ^ multiple; |
| 325 | * } |
| 326 | * With this optimization, the little-endian code is simpler: |
| 327 | * for (i = 0; i < input_bits; i++) { |
| 328 | * remainder ^= next_input_bit(); |
| 329 | * multiple = (remainder & 1) ? CRCPOLY : 0; |
| 330 | * remainder = (remainder >> 1) ^ multiple; |
| 331 | * } |
| 332 | * |
| 333 | * Note that the other details of endianness have been hidden in CRCPOLY |
| 334 | * (which must be bit-reversed) and next_input_bit(). |
| 335 | * |
| 336 | * However, as long as next_input_bit is returning the bits in a sensible |
| 337 | * order, we can actually do the merging 8 or more bits at a time rather |
| 338 | * than one bit at a time: |
| 339 | * for (i = 0; i < input_bytes; i++) { |
| 340 | * remainder ^= next_input_byte() << 24; |
| 341 | * for (j = 0; j < 8; j++) { |
| 342 | * multiple = (remainder & 0x80000000) ? CRCPOLY : 0; |
| 343 | * remainder = (remainder << 1) ^ multiple; |
| 344 | * } |
| 345 | * } |
| 346 | * Or in little-endian: |
| 347 | * for (i = 0; i < input_bytes; i++) { |
| 348 | * remainder ^= next_input_byte(); |
| 349 | * for (j = 0; j < 8; j++) { |
| 350 | * multiple = (remainder & 1) ? CRCPOLY : 0; |
| 351 | * remainder = (remainder << 1) ^ multiple; |
| 352 | * } |
| 353 | * } |
| 354 | * If the input is a multiple of 32 bits, you can even XOR in a 32-bit |
| 355 | * word at a time and increase the inner loop count to 32. |
| 356 | * |
| 357 | * You can also mix and match the two loop styles, for example doing the |
| 358 | * bulk of a message byte-at-a-time and adding bit-at-a-time processing |
| 359 | * for any fractional bytes at the end. |
| 360 | * |
| 361 | * The only remaining optimization is to the byte-at-a-time table method. |
| 362 | * Here, rather than just shifting one bit of the remainder to decide |
| 363 | * in the correct multiple to subtract, we can shift a byte at a time. |
| 364 | * This produces a 40-bit (rather than a 33-bit) intermediate remainder, |
| 365 | * but again the multiple of the polynomial to subtract depends only on |
| 366 | * the high bits, the high 8 bits in this case. |
| 367 | * |
| 368 | * The multile we need in that case is the low 32 bits of a 40-bit |
| 369 | * value whose high 8 bits are given, and which is a multiple of the |
| 370 | * generator polynomial. This is simply the CRC-32 of the given |
| 371 | * one-byte message. |
| 372 | * |
| 373 | * Two more details: normally, appending zero bits to a message which |
| 374 | * is already a multiple of a polynomial produces a larger multiple of that |
| 375 | * polynomial. To enable a CRC to detect this condition, it's common to |
| 376 | * invert the CRC before appending it. This makes the remainder of the |
| 377 | * message+crc come out not as zero, but some fixed non-zero value. |
| 378 | * |
| 379 | * The same problem applies to zero bits prepended to the message, and |
| 380 | * a similar solution is used. Instead of starting with a remainder of |
| 381 | * 0, an initial remainder of all ones is used. As long as you start |
| 382 | * the same way on decoding, it doesn't make a difference. |
| 383 | */ |
| 384 | |
| 385 | #ifdef UNITTEST |
| 386 | |
| 387 | #include <stdlib.h> |
| 388 | #include <stdio.h> |
| 389 | |
| 390 | #ifdef UBI_LINUX /*Not used at present */ |
| 391 | static void |
| 392 | buf_dump(char const *prefix, unsigned char const *buf, size_t len) |
| 393 | { |
| 394 | fputs(prefix, stdout); |
| 395 | while (len--) |
| 396 | printf(" %02x", *buf++); |
| 397 | putchar('\n'); |
| 398 | |
| 399 | } |
| 400 | #endif |
| 401 | |
| 402 | static void bytereverse(unsigned char *buf, size_t len) |
| 403 | { |
| 404 | while (len--) { |
| 405 | unsigned char x = bitrev8(*buf); |
| 406 | *buf++ = x; |
| 407 | } |
| 408 | } |
| 409 | |
| 410 | static void random_garbage(unsigned char *buf, size_t len) |
| 411 | { |
| 412 | while (len--) |
| 413 | *buf++ = (unsigned char) random(); |
| 414 | } |
| 415 | |
| 416 | #ifdef UBI_LINUX /* Not used at present */ |
| 417 | static void store_le(u32 x, unsigned char *buf) |
| 418 | { |
| 419 | buf[0] = (unsigned char) x; |
| 420 | buf[1] = (unsigned char) (x >> 8); |
| 421 | buf[2] = (unsigned char) (x >> 16); |
| 422 | buf[3] = (unsigned char) (x >> 24); |
| 423 | } |
| 424 | #endif |
| 425 | |
| 426 | static void store_be(u32 x, unsigned char *buf) |
| 427 | { |
| 428 | buf[0] = (unsigned char) (x >> 24); |
| 429 | buf[1] = (unsigned char) (x >> 16); |
| 430 | buf[2] = (unsigned char) (x >> 8); |
| 431 | buf[3] = (unsigned char) x; |
| 432 | } |
| 433 | |
| 434 | /* |
| 435 | * This checks that CRC(buf + CRC(buf)) = 0, and that |
| 436 | * CRC commutes with bit-reversal. This has the side effect |
| 437 | * of bytewise bit-reversing the input buffer, and returns |
| 438 | * the CRC of the reversed buffer. |
| 439 | */ |
| 440 | static u32 test_step(u32 init, unsigned char *buf, size_t len) |
| 441 | { |
| 442 | u32 crc1, crc2; |
| 443 | size_t i; |
| 444 | |
| 445 | crc1 = crc32_be(init, buf, len); |
| 446 | store_be(crc1, buf + len); |
| 447 | crc2 = crc32_be(init, buf, len + 4); |
| 448 | if (crc2) |
| 449 | printf("\nCRC cancellation fail: 0x%08x should be 0\n", |
| 450 | crc2); |
| 451 | |
| 452 | for (i = 0; i <= len + 4; i++) { |
| 453 | crc2 = crc32_be(init, buf, i); |
| 454 | crc2 = crc32_be(crc2, buf + i, len + 4 - i); |
| 455 | if (crc2) |
| 456 | printf("\nCRC split fail: 0x%08x\n", crc2); |
| 457 | } |
| 458 | |
| 459 | /* Now swap it around for the other test */ |
| 460 | |
| 461 | bytereverse(buf, len + 4); |
| 462 | init = bitrev32(init); |
| 463 | crc2 = bitrev32(crc1); |
| 464 | if (crc1 != bitrev32(crc2)) |
| 465 | printf("\nBit reversal fail: 0x%08x -> 0x%08x -> 0x%08x\n", |
| 466 | crc1, crc2, bitrev32(crc2)); |
| 467 | crc1 = crc32_le(init, buf, len); |
| 468 | if (crc1 != crc2) |
| 469 | printf("\nCRC endianness fail: 0x%08x != 0x%08x\n", crc1, |
| 470 | crc2); |
| 471 | crc2 = crc32_le(init, buf, len + 4); |
| 472 | if (crc2) |
| 473 | printf("\nCRC cancellation fail: 0x%08x should be 0\n", |
| 474 | crc2); |
| 475 | |
| 476 | for (i = 0; i <= len + 4; i++) { |
| 477 | crc2 = crc32_le(init, buf, i); |
| 478 | crc2 = crc32_le(crc2, buf + i, len + 4 - i); |
| 479 | if (crc2) |
| 480 | printf("\nCRC split fail: 0x%08x\n", crc2); |
| 481 | } |
| 482 | |
| 483 | return crc1; |
| 484 | } |
| 485 | |
| 486 | #define SIZE 64 |
| 487 | #define INIT1 0 |
| 488 | #define INIT2 0 |
| 489 | |
| 490 | int main(void) |
| 491 | { |
| 492 | unsigned char buf1[SIZE + 4]; |
| 493 | unsigned char buf2[SIZE + 4]; |
| 494 | unsigned char buf3[SIZE + 4]; |
| 495 | int i, j; |
| 496 | u32 crc1, crc2, crc3; |
| 497 | |
| 498 | for (i = 0; i <= SIZE; i++) { |
| 499 | printf("\rTesting length %d...", i); |
| 500 | fflush(stdout); |
| 501 | random_garbage(buf1, i); |
| 502 | random_garbage(buf2, i); |
| 503 | for (j = 0; j < i; j++) |
| 504 | buf3[j] = buf1[j] ^ buf2[j]; |
| 505 | |
| 506 | crc1 = test_step(INIT1, buf1, i); |
| 507 | crc2 = test_step(INIT2, buf2, i); |
| 508 | /* Now check that CRC(buf1 ^ buf2) = CRC(buf1) ^ CRC(buf2) */ |
| 509 | crc3 = test_step(INIT1 ^ INIT2, buf3, i); |
| 510 | if (crc3 != (crc1 ^ crc2)) |
| 511 | printf("CRC XOR fail: 0x%08x != 0x%08x ^ 0x%08x\n", |
| 512 | crc3, crc1, crc2); |
| 513 | } |
| 514 | printf("\nAll test complete. No failures expected.\n"); |
| 515 | return 0; |
| 516 | } |
| 517 | |
| 518 | #endif /* UNITTEST */ |