From d827181d0dfcebffbc02554fdf04606b325341dd Mon Sep 17 00:00:00 2001 From: John Kohl Date: Mon, 3 Dec 1990 15:39:56 +0000 Subject: [PATCH] use proper polynomial for this CRC table git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@1525 dc483132-0cff-0310-8789-dd5450dbe970 --- src/lib/crypto/crc32/crc.c | 179 +++++++++++++++++++++++-------------- 1 file changed, 114 insertions(+), 65 deletions(-) diff --git a/src/lib/crypto/crc32/crc.c b/src/lib/crypto/crc32/crc.c index 27b35f638..be63e0066 100644 --- a/src/lib/crypto/crc32/crc.c +++ b/src/lib/crypto/crc32/crc.c @@ -7,7 +7,7 @@ * For copying and distribution information, please see the file * . * - * CRC-32 routines + * CRC-32/AUTODIN-II routines */ #if !defined(lint) && !defined(SABER) @@ -20,71 +20,120 @@ static char rcsid_crc_c[] = #include #include +/* This table and block of comments are taken from code labeled: */ +/* + * Copyright (C) 1986 Gary S. Brown. You may use this program, or + * code or tables extracted from it, as desired without restriction. + */ + +/* First, the polynomial itself and its table of feedback terms. The */ +/* polynomial is */ +/* 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+X^0 */ +/* Note that we take it "backwards" and put the highest-order term in */ +/* the lowest-order bit. The X^32 term is "implied"; the LSB is the */ +/* X^31 term, etc. The X^0 term (usually shown as "+1") results in */ +/* the MSB being 1. */ + +/* Note that the usual hardware shift register implementation, which */ +/* is what we're using (we're merely optimizing it by doing eight-bit */ +/* chunks at a time) shifts bits into the lowest-order term. In our */ +/* implementation, that means shifting towards the right. Why do we */ +/* do it this way? Because the calculated CRC must be transmitted in */ +/* order from highest-order term to lowest-order term. UARTs transmit */ +/* characters in order from LSB to MSB. By storing the CRC this way, */ +/* we hand it to the UART in the order low-byte to high-byte; the UART */ +/* sends each low-bit to hight-bit; and the result is transmission bit */ +/* by bit from highest- to lowest-order term without requiring any bit */ +/* shuffling on our part. Reception works similarly. */ + +/* The feedback terms table consists of 256, 32-bit entries. Notes: */ +/* */ +/* 1. The table can be generated at runtime if desired; code to do so */ +/* is shown later. It might not be obvious, but the feedback */ +/* terms simply represent the results of eight shift/xor opera- */ +/* tions for all combinations of data and CRC register values. */ +/* */ +/* 2. The CRC accumulation logic is the same for all CRC polynomials, */ +/* be they sixteen or thirty-two bits wide. You simply choose the */ +/* appropriate table. Alternatively, because the table can be */ +/* generated at runtime, you can start by generating the table for */ +/* the polynomial in question and use exactly the same "updcrc", */ +/* if your application needn't simultaneously handle two CRC */ +/* polynomials. (Note, however, that XMODEM is strange.) */ +/* */ +/* 3. For 16-bit CRCs, the table entries need be only 16 bits wide; */ +/* of course, 32-bit entries work OK if the high 16 bits are zero. */ +/* */ +/* 4. The values must be right-shifted by eight bits by the "updcrc" */ +/* logic; the shift must be unsigned (bring in zeroes). On some */ +/* hardware you could probably optimize the shift in assembler by */ +/* using byte-swap instructions. */ + static u_long const crc_table[256] = { - 0x00000000, 0x01080082, 0x02100104, 0x03180186, - 0x04200208, 0x0528028a, 0x0630030c, 0x0738038e, - 0x08400410, 0x09480492, 0x0a500514, 0x0b580596, - 0x0c600618, 0x0d68069a, 0x0e70071c, 0x0f78079e, - 0x10800820, 0x118808a2, 0x12900924, 0x139809a6, - 0x14a00a28, 0x15a80aaa, 0x16b00b2c, 0x17b80bae, - 0x18c00c30, 0x19c80cb2, 0x1ad00d34, 0x1bd80db6, - 0x1ce00e38, 0x1de80eba, 0x1ef00f3c, 0x1ff80fbe, - 0x21001040, 0x200810c2, 0x23101144, 0x221811c6, - 0x25201248, 0x242812ca, 0x2730134c, 0x263813ce, - 0x29401450, 0x284814d2, 0x2b501554, 0x2a5815d6, - 0x2d601658, 0x2c6816da, 0x2f70175c, 0x2e7817de, - 0x31801860, 0x308818e2, 0x33901964, 0x329819e6, - 0x35a01a68, 0x34a81aea, 0x37b01b6c, 0x36b81bee, - 0x39c01c70, 0x38c81cf2, 0x3bd01d74, 0x3ad81df6, - 0x3de01e78, 0x3ce81efa, 0x3ff01f7c, 0x3ef81ffe, - 0x42002080, 0x43082002, 0x40102184, 0x41182106, - 0x46202288, 0x4728220a, 0x4430238c, 0x4538230e, - 0x4a402490, 0x4b482412, 0x48502594, 0x49582516, - 0x4e602698, 0x4f68261a, 0x4c70279c, 0x4d78271e, - 0x528028a0, 0x53882822, 0x509029a4, 0x51982926, - 0x56a02aa8, 0x57a82a2a, 0x54b02bac, 0x55b82b2e, - 0x5ac02cb0, 0x5bc82c32, 0x58d02db4, 0x59d82d36, - 0x5ee02eb8, 0x5fe82e3a, 0x5cf02fbc, 0x5df82f3e, - 0x630030c0, 0x62083042, 0x611031c4, 0x60183146, - 0x672032c8, 0x6628324a, 0x653033cc, 0x6438334e, - 0x6b4034d0, 0x6a483452, 0x695035d4, 0x68583556, - 0x6f6036d8, 0x6e68365a, 0x6d7037dc, 0x6c78375e, - 0x738038e0, 0x72883862, 0x719039e4, 0x70983966, - 0x77a03ae8, 0x76a83a6a, 0x75b03bec, 0x74b83b6e, - 0x7bc03cf0, 0x7ac83c72, 0x79d03df4, 0x78d83d76, - 0x7fe03ef8, 0x7ee83e7a, 0x7df03ffc, 0x7cf83f7e, - 0x84004100, 0x85084182, 0x86104004, 0x87184086, - 0x80204308, 0x8128438a, 0x8230420c, 0x8338428e, - 0x8c404510, 0x8d484592, 0x8e504414, 0x8f584496, - 0x88604718, 0x8968479a, 0x8a70461c, 0x8b78469e, - 0x94804920, 0x958849a2, 0x96904824, 0x979848a6, - 0x90a04b28, 0x91a84baa, 0x92b04a2c, 0x93b84aae, - 0x9cc04d30, 0x9dc84db2, 0x9ed04c34, 0x9fd84cb6, - 0x98e04f38, 0x99e84fba, 0x9af04e3c, 0x9bf84ebe, - 0xa5005140, 0xa40851c2, 0xa7105044, 0xa61850c6, - 0xa1205348, 0xa02853ca, 0xa330524c, 0xa23852ce, - 0xad405550, 0xac4855d2, 0xaf505454, 0xae5854d6, - 0xa9605758, 0xa86857da, 0xab70565c, 0xaa7856de, - 0xb5805960, 0xb48859e2, 0xb7905864, 0xb69858e6, - 0xb1a05b68, 0xb0a85bea, 0xb3b05a6c, 0xb2b85aee, - 0xbdc05d70, 0xbcc85df2, 0xbfd05c74, 0xbed85cf6, - 0xb9e05f78, 0xb8e85ffa, 0xbbf05e7c, 0xbaf85efe, - 0xc6006180, 0xc7086102, 0xc4106084, 0xc5186006, - 0xc2206388, 0xc328630a, 0xc030628c, 0xc138620e, - 0xce406590, 0xcf486512, 0xcc506494, 0xcd586416, - 0xca606798, 0xcb68671a, 0xc870669c, 0xc978661e, - 0xd68069a0, 0xd7886922, 0xd49068a4, 0xd5986826, - 0xd2a06ba8, 0xd3a86b2a, 0xd0b06aac, 0xd1b86a2e, - 0xdec06db0, 0xdfc86d32, 0xdcd06cb4, 0xddd86c36, - 0xdae06fb8, 0xdbe86f3a, 0xd8f06ebc, 0xd9f86e3e, - 0xe70071c0, 0xe6087142, 0xe51070c4, 0xe4187046, - 0xe32073c8, 0xe228734a, 0xe13072cc, 0xe038724e, - 0xef4075d0, 0xee487552, 0xed5074d4, 0xec587456, - 0xeb6077d8, 0xea68775a, 0xe97076dc, 0xe878765e, - 0xf78079e0, 0xf6887962, 0xf59078e4, 0xf4987866, - 0xf3a07be8, 0xf2a87b6a, 0xf1b07aec, 0xf0b87a6e, - 0xffc07df0, 0xfec87d72, 0xfdd07cf4, 0xfcd87c76, - 0xfbe07ff8, 0xfae87f7a, 0xf9f07efc, 0xf8f87e7e + 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, + 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, + 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, + 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, + 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, + 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, + 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, + 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, + 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, + 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, + 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, + 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, + 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, + 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, + 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, + 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, + 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, + 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, + 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, + 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, + 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, + 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, + 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, + 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, + 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, + 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, + 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, + 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, + 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, + 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, + 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, + 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, + 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, + 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, + 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, + 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, + 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, + 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, + 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, + 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, + 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, + 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, + 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, + 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, + 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, + 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, + 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, + 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, + 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, + 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, + 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, + 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, + 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, + 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, + 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, + 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, + 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, + 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, + 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, + 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, + 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, + 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, + 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, + 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d }; static krb5_error_code -- 2.26.2