larimer@ncrcam.Cambridge.NCR.COM (Fred Larimer) (10/24/90)
I hope somebody can help me with this. I need to write a routine to generate a crc32 frame check sequence in software. I've read the description of the Autodin II CRC32 frame check sequence in the IEEE 802.3 Standard 1988, but so far I haven't been able to convert that description to an algorithm that I can code to. So, if anybody can help me with an algorithm, a routine, a function or a source reference for any of the above I would appreciate it. Fred.
rbt@cernvax.UUCP (roberto divia) (10/25/90)
Fred Larimer asked for an implementation of the Autodin II CRC32 cheker. This is written using CERN macros. Hope it will be readable... IDENT CHIFC_CRC_CHECK TTL 'CHIFC CRC Generator/Checker' STTL 'Module history' ******************************************************************************** * * CHIFC CRC Generator/Checker * =========================== * * Modification history: * 5 Sep 89 Created (RD) * * General comment: this code is completely reentrant and it should be extremely * fast since the kernel is small enough to be cached in the program cache of the * 68020/68030. The data cache should not make a big difference. * ******************************************************************************** STTL 'EQU Declarations' PAGE ******************************************************************************** * * EQU Declarations * ================ * PROGRAM SECTION R * OPT P=68020 * NOLIST SYSTEXT LIST CREF * * CRC polynomial term: * -------------------- * POLY EQU %00000100110000010001110110110111 As for Ethernet prot. * EXPECT EQU %11000111000001001101110101111011 As before, this is the * expected value by the * CRC checker. * ******************************************************************************** STTL 'CRC Generator initialisation' PAGE ******************************************************************************** * * CRC Generator initialisation * ---------------------------- * * procedure initialise_CRC; * * This entry must be called before using the CRC generator/checker, to "warm up" * the table of CRC constants. * S_Entry initialise_CRC Main entry point S_Entry _initialise_CRC For C programs S_Entry iniCRC For FORTRAN programs * lea CRC_t,a0 Load the CRC table base address (low b) clr.l d1 Initial byte value move.l #POLY,d7 Load the polynomial term IextL move.b d1,d2 Load the current byte value moveq.l #7,d3 Initialise the bit counter (7 + 1) clr.l d0 Initial CRC value (all zeros) IintL rol.b #1,d2 Get the top bit (# 7) in position 0 lsl.l #1,d0 Prepare the next CRC roxl.b #1,d4 Get the top bit of the CRC into d4 bit 0 eor.b d2,d4 Xor the patterns btst.b #0,d4 Bit 0 is zero? beq.b IdivZ Skip if true eor.l d7,d0 Otherwise xor the CRC with the POLY... or.b #1,d0 ...and set bit 0 IdivZ dbra.w d3,IintL Loop on all bits move.l d0,(a0)+ Done: save the generated CRC value addq.b #1,d1 Increment the byte count bne.b IextL And loop on all the possible patterns rts * ******************************************************************************** STTL 'CRC Generator' PAGE ******************************************************************************** * * CRC Generator * ------------- * * procedure generate_CRC( VAR data_buffer : INTEGER [1..num_longwords]; * VAR num_longwords : INTEGER ); * * The data_buffer is scanned and the generated CRC is appended after * num_longwords + 1. * * All input parameters are passed by ADDRESS for FORTRAN compatibility. * S_Entry generate_CRC Main entry point S_Entry _generate_CRC For C programs S_Entry genCRC For FORTRAN programs * bsr.b do_CRC Generate the CRC eor.l #-1,d0 Negate the pattern... move.l d0,(a0) ...and save it rts * ******************************************************************************** STTL 'CRC Checker' PAGE ******************************************************************************** * * CRC Checker * ----------- * * function check_CRC ( VAR data_buffer : INTEGER [1..num_longwords]; * VAR num_longwords : INTEGER ) : UNSIGNED; * * The data_buffer is scanned for num_longwords and the CRC is checked. The * function returns 0 if the check succedes. This procedure assumes that the * last longword if the data_buffer contains the CRC generated by generate_CRC. * * All input parameters are passed by ADDRESS for FORTRAN compatibility. * S_Entry check_CRC Main entry point S_Entry _check_CRC For C programs S_Entry chkCRC For FORTRAN programs * bsr.b do_CRC Generate the expected CRC sub.l #EXPECT,d0 Expected value? d0 MUST be = 0 rts * ******************************************************************************** STTL 'CRC generator' PAGE ******************************************************************************** * * CRC generator * ============= * * This procedure is called with this stack organisation: * * a7 -> "internal" return address * +4 -> "external" return address * +8 -> buffer address * +C -> number of longwords in the buffer * * It returns in d0 the generated CRC and in a0 the address of the first * unused longword. * do_CRC move.l 8(a7),a0 Fetch the data array address move.l ([$C,a7]),d1 Fetch the number of longwords counter asl.l #2,d1 Compute the byte count moveq.l #-1,d0 Preload the Remainder lea CRC_t,a1 Fetch the CRC table base address moveq.l #0,d2 bra endOfL Start looping * * Here starts the Main Loop * mainL rol.l #8,d0 Get the top remainder byte in low byte move.b (a0)+,d3 Get current data pattern move.b d0,d2 Move the bottom CRC byte into d2 move.b #0,d0 Clear the remainder bottom byte eor.b d3,d2 Compute the table index move.l (a1,d2.W*4),d4 Retrieve the remainder from the table... eor.l d4,d0 ...and compute the current CRC endOfL dbra.w d1,mainL Loop on all the bytes rts * ******************************************************************************** STTL 'CRC Generator (Bit oriented)' PAGE ******************************************************************************** * * CRC Generator (Bit oriented) * ---------------------------- * * procedure Bgenerate_CRC(VAR data_buffer : INTEGER [1..num_longwords]; * VAR num_longwords : INTEGER ); * * The data_buffer is scanned and the generated CRC is appended after * num_longwords + 1. * * All input parameters are passed by ADDRESS for FORTRAN compatibility. * S_Entry Bgenerate_CRC Main entry point * bsr.b private Generate the CRC eor.l #-1,d0 Negate the pattern... move.l d0,(a0) ...and save it rts * ******************************************************************************** STTL 'CRC Checker (Bit oriented)' PAGE ******************************************************************************** * * CRC Checker (Bit oriented) * -------------------------- * * function Bcheck_CRC ( VAR data_buffer : INTEGER [1..num_longwords]; * VAR num_longwords : INTEGER ) : UNSIGNED; * * The data_buffer is scanned for num_longwords and the CRC is checked. The * function returns 0 if the check succedes. This procedure assumes that the * last longword if the data_buffer contains the CRC generated by generate_CRC. * * All input parameters are passed by ADDRESS for FORTRAN compatibility. * S_Entry Bcheck_CRC Main entry point * bsr.b private Generate the expected CRC sub.l #EXPECT,d0 Expected value? d0 MUST be = 0 rts * ******************************************************************************** STTL 'CRC generator (Bit oriented)' PAGE ******************************************************************************** * * CRC generator (Bit oriented) * ============================ * * This procedure is called with this stack organisation: * * a7 -> "internal" return address * +4 -> "external" return address * +8 -> buffer address * +C -> number of longwords in the buffer * * It returns in d0 the generated CRC and in a0 the address of the first * unused longword. * private move.l 8(a7),a0 Fetch the data array address move.l ([$C,a7]),d1 Fetch the number of longwords counter moveq.l #-1,d0 Preload the CRC accumulator to all 1s move.l #POLY,d7 d7 contains the polynomial term bra BendOfL Start looping * * Here starts the Main Loop * BmainL move.l (a0)+,d2 Fetch the current Lw moveq.l #31,d3 Load the bits count - 1 BbitsL rol.l #1,d2 Get the current bit in position 0 lsl.l #1,d0 Start making the next CRC roxl.b #1,d4 Get into d4 bit 0 the Shift out eor.b d2,d4 Exor (only bit 0 is interesting) btst.b #0,d4 Bit is zero? beq.b BdivZ If true, skip next phase eor.l d7,d0 Otherwise xor CRC with the POLY... or.b #1,d0 ...and set bit 0 BdivZ dbra.w d3,BbitsL Loop on all the data bits BendOfL dbra.w d1,BmainL Loop on all the Lws in the buffer rts * ******************************************************************************** STTL 'Data area' PAGE ******************************************************************************** * * Data area * --------- * UNINDATA SECTION R * ENTRY CRC_t For debugging... CRC_t DS.L 256 CRC table (loaded by initialise_CRC) * ******************************************************************************** STTL '' PAGE END -- | Roberto Divia` | Love at first sight is one of the greatest | | ============= | labor-saving devices the world has ever seen | | CERN : European Laboratory for Particle Physics, 1211 Geneva 23 | | Switzerland (CH) |
syackey@secola.Columbia.NCR.COM (Steve Yackey) (10/26/90)
In article <2117@ncrcam.Cambridge.NCR.COM> larimer@ncrcam.Cambridge.NCR.COM (Fred Larimer) writes: >I hope somebody can help me with this. > >I need to write a routine to generate a crc32 frame check sequence in software. > >I've read the description of the Autodin II CRC32 frame check sequence in the >IEEE 802.3 Standard 1988, but so far I haven't been able to convert that >description to an algorithm that I can code to. > >So, if anybody can help me with an algorithm, a routine, a function or a >source reference for any of the above I would appreciate it. > >Fred. /* * This code implements the AUTODIN II polynomial used by Ethernet, * and can be used to calculate multicast address hash indices. * It assumes that the low order bits will be transmitted first, * and consequently the low byte should be sent first when * the crc computation is finished. The crc should be complemented * before transmission. * The variable corresponding to the macro argument "crc" should * be an unsigned long and should be preset to all ones for Ethernet * use. An error-free packet will leave 0xDEBB20E3 in the crc. * Spencer Garrett <srg@quick.com> */ #define CRC(crc, ch) (crc = (crc >> 8) ^ crctab[(crc ^ (ch)) & 0xff]) /* generated using the AUTODIN II 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 + 1 */ unsigned long crctab[256] = { 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, }; #include <stdio.h> main() { unsigned long crc = 0xFFFFFFFF; int i; while (scanf(" %x", &i) == 1) CRC(crc, i); printf("crc 0x%08x comp 0x%08x\n", crc, ~crc); }
sasrer@unx.sas.com (Rodney Radford) (11/06/90)
In article <2117@ncrcam.Cambridge.NCR.COM> larimer@ncrcam.Cambridge.NCR.COM (Fred Larimer) writes: >I hope somebody can help me with this. > >I need to write a routine to generate a crc32 frame check sequence in software. > >I've read the description of the Autodin II CRC32 frame check sequence in the >IEEE 802.3 Standard 1988, but so far I haven't been able to convert that >description to an algorithm that I can code to. > >So, if anybody can help me with an algorithm, a routine, a function or a >source reference for any of the above I would appreciate it. > >Fred. An article in Steve Ciarcia's magazine "Circuit Cellar" showed just such an algorithm coded in C. I am currently at work so I don't have my magazines handy, but if you want more information, I can get the actual issue number later.... -- Rodney E. Radford SAS Institute, Inc. sasrer@unx.sas.com DG/UX AViiON developer Box 8000, Cary, NC 27512 (919) 677-8000 x7703