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Diffstat (limited to 'src/base/crc.cc')
| -rw-r--r-- | src/base/crc.cc | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/src/base/crc.cc b/src/base/crc.cc new file mode 100644 index 000000000..08f039577 --- /dev/null +++ b/src/base/crc.cc @@ -0,0 +1,114 @@ +/* + * Copyright (c) 1988, 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <string> + +#include "sim/host.hh" +#include "base/crc.hh" + +#define ETHER_CRC_POLY_LE 0xedb88320 +#define ETHER_CRC_POLY_BE 0x04c11db6 + +#if 0 +/* + * This is for reference. We have a table-driven version + * of the little-endian crc32 generator, which is faster + * than the double-loop. + */ +uint32_t +crc32le(const uint8_t *buf, size_t len) +{ + uint32_t c, crc, carry; + size_t i, j; + + crc = 0xffffffffU; /* initial value */ + + for (i = 0; i < len; i++) { + c = buf[i]; + for (j = 0; j < 8; j++) { + carry = ((crc & 0x01) ? 1 : 0) ^ (c & 0x01); + crc >>= 1; + c >>= 1; + if (carry) + crc = (crc ^ ETHER_CRC_POLY_LE); + } + } + + return (crc); +} +#else +uint32_t +crc32le(const uint8_t *buf, size_t len) +{ + static const uint32_t crctab[] = { + 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, + 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c, + 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, + 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c + }; + uint32_t crc; + int i; + + crc = 0xffffffffU; /* initial value */ + + for (i = 0; i < len; i++) { + crc ^= buf[i]; + crc = (crc >> 4) ^ crctab[crc & 0xf]; + crc = (crc >> 4) ^ crctab[crc & 0xf]; + } + + return (crc); +} +#endif + +uint32_t +crc32be(const uint8_t *buf, size_t len) +{ + uint32_t c, crc, carry; + size_t i, j; + + crc = 0xffffffffU; /* initial value */ + + for (i = 0; i < len; i++) { + c = buf[i]; + for (j = 0; j < 8; j++) { + carry = ((crc & 0x80000000U) ? 1 : 0) ^ (c & 0x01); + crc <<= 1; + c >>= 1; + if (carry) + crc = (crc ^ ETHER_CRC_POLY_BE) | carry; + } + } + + return (crc); +} |