1*76af099aSliuyi /* 2*76af099aSliuyi * (C) Copyright 2017 Fuzhou Rockchip Electronics Co., Ltd 3*76af099aSliuyi * Seth Liu 2017.03.01 4*76af099aSliuyi * 5*76af099aSliuyi * SPDX-License-Identifier: GPL-2.0+ 6*76af099aSliuyi */ 7*76af099aSliuyi #include "DefineHeader.h" 8*76af099aSliuyi UINT gTable_Crc32[256] = 9*76af099aSliuyi {//crfc32 factor 0x04C10DB7 10*76af099aSliuyi 0x00000000, 0x04c10db7, 0x09821b6e, 0x0d4316d9, 11*76af099aSliuyi 0x130436dc, 0x17c53b6b, 0x1a862db2, 0x1e472005, 12*76af099aSliuyi 0x26086db8, 0x22c9600f, 0x2f8a76d6, 0x2b4b7b61, 13*76af099aSliuyi 0x350c5b64, 0x31cd56d3, 0x3c8e400a, 0x384f4dbd, 14*76af099aSliuyi 0x4c10db70, 0x48d1d6c7, 0x4592c01e, 0x4153cda9, 15*76af099aSliuyi 0x5f14edac, 0x5bd5e01b, 0x5696f6c2, 0x5257fb75, 16*76af099aSliuyi 0x6a18b6c8, 0x6ed9bb7f, 0x639aada6, 0x675ba011, 17*76af099aSliuyi 0x791c8014, 0x7ddd8da3, 0x709e9b7a, 0x745f96cd, 18*76af099aSliuyi 0x9821b6e0, 0x9ce0bb57, 0x91a3ad8e, 0x9562a039, 19*76af099aSliuyi 0x8b25803c, 0x8fe48d8b, 0x82a79b52, 0x866696e5, 20*76af099aSliuyi 0xbe29db58, 0xbae8d6ef, 0xb7abc036, 0xb36acd81, 21*76af099aSliuyi 0xad2ded84, 0xa9ece033, 0xa4aff6ea, 0xa06efb5d, 22*76af099aSliuyi 0xd4316d90, 0xd0f06027, 0xddb376fe, 0xd9727b49, 23*76af099aSliuyi 0xc7355b4c, 0xc3f456fb, 0xceb74022, 0xca764d95, 24*76af099aSliuyi 0xf2390028, 0xf6f80d9f, 0xfbbb1b46, 0xff7a16f1, 25*76af099aSliuyi 0xe13d36f4, 0xe5fc3b43, 0xe8bf2d9a, 0xec7e202d, 26*76af099aSliuyi 0x34826077, 0x30436dc0, 0x3d007b19, 0x39c176ae, 27*76af099aSliuyi 0x278656ab, 0x23475b1c, 0x2e044dc5, 0x2ac54072, 28*76af099aSliuyi 0x128a0dcf, 0x164b0078, 0x1b0816a1, 0x1fc91b16, 29*76af099aSliuyi 0x018e3b13, 0x054f36a4, 0x080c207d, 0x0ccd2dca, 30*76af099aSliuyi 0x7892bb07, 0x7c53b6b0, 0x7110a069, 0x75d1adde, 31*76af099aSliuyi 0x6b968ddb, 0x6f57806c, 0x621496b5, 0x66d59b02, 32*76af099aSliuyi 0x5e9ad6bf, 0x5a5bdb08, 0x5718cdd1, 0x53d9c066, 33*76af099aSliuyi 0x4d9ee063, 0x495fedd4, 0x441cfb0d, 0x40ddf6ba, 34*76af099aSliuyi 0xaca3d697, 0xa862db20, 0xa521cdf9, 0xa1e0c04e, 35*76af099aSliuyi 0xbfa7e04b, 0xbb66edfc, 0xb625fb25, 0xb2e4f692, 36*76af099aSliuyi 0x8aabbb2f, 0x8e6ab698, 0x8329a041, 0x87e8adf6, 37*76af099aSliuyi 0x99af8df3, 0x9d6e8044, 0x902d969d, 0x94ec9b2a, 38*76af099aSliuyi 0xe0b30de7, 0xe4720050, 0xe9311689, 0xedf01b3e, 39*76af099aSliuyi 0xf3b73b3b, 0xf776368c, 0xfa352055, 0xfef42de2, 40*76af099aSliuyi 0xc6bb605f, 0xc27a6de8, 0xcf397b31, 0xcbf87686, 41*76af099aSliuyi 0xd5bf5683, 0xd17e5b34, 0xdc3d4ded, 0xd8fc405a, 42*76af099aSliuyi 0x6904c0ee, 0x6dc5cd59, 0x6086db80, 0x6447d637, 43*76af099aSliuyi 0x7a00f632, 0x7ec1fb85, 0x7382ed5c, 0x7743e0eb, 44*76af099aSliuyi 0x4f0cad56, 0x4bcda0e1, 0x468eb638, 0x424fbb8f, 45*76af099aSliuyi 0x5c089b8a, 0x58c9963d, 0x558a80e4, 0x514b8d53, 46*76af099aSliuyi 0x25141b9e, 0x21d51629, 0x2c9600f0, 0x28570d47, 47*76af099aSliuyi 0x36102d42, 0x32d120f5, 0x3f92362c, 0x3b533b9b, 48*76af099aSliuyi 0x031c7626, 0x07dd7b91, 0x0a9e6d48, 0x0e5f60ff, 49*76af099aSliuyi 0x101840fa, 0x14d94d4d, 0x199a5b94, 0x1d5b5623, 50*76af099aSliuyi 0xf125760e, 0xf5e47bb9, 0xf8a76d60, 0xfc6660d7, 51*76af099aSliuyi 0xe22140d2, 0xe6e04d65, 0xeba35bbc, 0xef62560b, 52*76af099aSliuyi 0xd72d1bb6, 0xd3ec1601, 0xdeaf00d8, 0xda6e0d6f, 53*76af099aSliuyi 0xc4292d6a, 0xc0e820dd, 0xcdab3604, 0xc96a3bb3, 54*76af099aSliuyi 0xbd35ad7e, 0xb9f4a0c9, 0xb4b7b610, 0xb076bba7, 55*76af099aSliuyi 0xae319ba2, 0xaaf09615, 0xa7b380cc, 0xa3728d7b, 56*76af099aSliuyi 0x9b3dc0c6, 0x9ffccd71, 0x92bfdba8, 0x967ed61f, 57*76af099aSliuyi 0x8839f61a, 0x8cf8fbad, 0x81bbed74, 0x857ae0c3, 58*76af099aSliuyi 0x5d86a099, 0x5947ad2e, 0x5404bbf7, 0x50c5b640, 59*76af099aSliuyi 0x4e829645, 0x4a439bf2, 0x47008d2b, 0x43c1809c, 60*76af099aSliuyi 0x7b8ecd21, 0x7f4fc096, 0x720cd64f, 0x76cddbf8, 61*76af099aSliuyi 0x688afbfd, 0x6c4bf64a, 0x6108e093, 0x65c9ed24, 62*76af099aSliuyi 0x11967be9, 0x1557765e, 0x18146087, 0x1cd56d30, 63*76af099aSliuyi 0x02924d35, 0x06534082, 0x0b10565b, 0x0fd15bec, 64*76af099aSliuyi 0x379e1651, 0x335f1be6, 0x3e1c0d3f, 0x3add0088, 65*76af099aSliuyi 0x249a208d, 0x205b2d3a, 0x2d183be3, 0x29d93654, 66*76af099aSliuyi 0xc5a71679, 0xc1661bce, 0xcc250d17, 0xc8e400a0, 67*76af099aSliuyi 0xd6a320a5, 0xd2622d12, 0xdf213bcb, 0xdbe0367c, 68*76af099aSliuyi 0xe3af7bc1, 0xe76e7676, 0xea2d60af, 0xeeec6d18, 69*76af099aSliuyi 0xf0ab4d1d, 0xf46a40aa, 0xf9295673, 0xfde85bc4, 70*76af099aSliuyi 0x89b7cd09, 0x8d76c0be, 0x8035d667, 0x84f4dbd0, 71*76af099aSliuyi 0x9ab3fbd5, 0x9e72f662, 0x9331e0bb, 0x97f0ed0c, 72*76af099aSliuyi 0xafbfa0b1, 0xab7ead06, 0xa63dbbdf, 0xa2fcb668, 73*76af099aSliuyi 0xbcbb966d, 0xb87a9bda, 0xb5398d03, 0xb1f880b4, 74*76af099aSliuyi }; 75*76af099aSliuyi #define rr_max 104 /* Number of parity checks, rr = deg[g(x)] */ 76*76af099aSliuyi #define parallel 8 //bit count 77*76af099aSliuyi #define mm 13//limit count 78*76af099aSliuyi #define nn 8191//code size 79*76af099aSliuyi #define kk 4120//info length 80*76af099aSliuyi #define tt 8//correct count 81*76af099aSliuyi 82*76af099aSliuyi #define tt2 2*tt 83*76af099aSliuyi UINT s[tt2+1]; // Syndrome values 84*76af099aSliuyi 85*76af099aSliuyi UINT rr;//redundant length // BCH code parameters 86*76af099aSliuyi 87*76af099aSliuyi 88*76af099aSliuyi UINT p[mm + 1]; 89*76af099aSliuyi UINT alpha_to[nn+1], index_of[nn+1] ; // Galois field 90*76af099aSliuyi UINT gg[rr_max+1] ; // Generator polynomial 91*76af099aSliuyi 92*76af099aSliuyi UINT ggx1=0; 93*76af099aSliuyi UINT ggx2=0; 94*76af099aSliuyi UINT ggx3=0; 95*76af099aSliuyi UINT ggx4=0; 96*76af099aSliuyi // get crc32 value 97*76af099aSliuyi UINT CRC_32(unsigned char* pData, UINT ulSize) 98*76af099aSliuyi { 99*76af099aSliuyi UINT i; 100*76af099aSliuyi UINT nAccum = 0; 101*76af099aSliuyi 102*76af099aSliuyi for ( i=0; i<ulSize; i++) 103*76af099aSliuyi nAccum = (nAccum<<8)^gTable_Crc32[(nAccum>>24)^(*pData++)]; 104*76af099aSliuyi return nAccum; 105*76af099aSliuyi } 106*76af099aSliuyi #define CRC16_CCITT 0x1021 //CRC operator 107*76af099aSliuyi void CRCBuildTable16(unsigned short aPoly , unsigned short *crcTable) 108*76af099aSliuyi { 109*76af099aSliuyi unsigned short i, j; 110*76af099aSliuyi unsigned short nData; 111*76af099aSliuyi unsigned short nAccum; 112*76af099aSliuyi 113*76af099aSliuyi for (i = 0; i < 256; i++) 114*76af099aSliuyi { 115*76af099aSliuyi nData = (unsigned short)(i << 8); 116*76af099aSliuyi nAccum = 0; 117*76af099aSliuyi for (j = 0; j < 8; j++) 118*76af099aSliuyi { 119*76af099aSliuyi if ((nData ^ nAccum) & 0x8000) 120*76af099aSliuyi nAccum = (nAccum << 1) ^ aPoly; 121*76af099aSliuyi else 122*76af099aSliuyi nAccum <<= 1; 123*76af099aSliuyi nData <<= 1; 124*76af099aSliuyi } 125*76af099aSliuyi crcTable[i] = nAccum; 126*76af099aSliuyi } 127*76af099aSliuyi } 128*76af099aSliuyi 129*76af099aSliuyi unsigned short CRC_16(unsigned char* aData, UINT aSize) 130*76af099aSliuyi { 131*76af099aSliuyi UINT i; 132*76af099aSliuyi unsigned short nAccum = 0; 133*76af099aSliuyi unsigned short crcTable[256]; 134*76af099aSliuyi 135*76af099aSliuyi CRCBuildTable16(CRC16_CCITT , crcTable); 136*76af099aSliuyi for (i = 0; i < aSize; i++) 137*76af099aSliuyi nAccum = (nAccum << 8) ^ crcTable[(nAccum >> 8) ^ *aData++]; 138*76af099aSliuyi 139*76af099aSliuyi return nAccum; 140*76af099aSliuyi } 141*76af099aSliuyi 142*76af099aSliuyi void P_RC4(unsigned char* buf, unsigned short len) 143*76af099aSliuyi { 144*76af099aSliuyi unsigned char S[256],K[256],temp; 145*76af099aSliuyi unsigned short i,j,t,x; 146*76af099aSliuyi unsigned char key[16]={124,78,3,4,85,5,9,7,45,44,123,56,23,13,23,17}; 147*76af099aSliuyi 148*76af099aSliuyi j = 0; 149*76af099aSliuyi for(i=0; i<256; i++){ 150*76af099aSliuyi S[i] = (unsigned char)i; 151*76af099aSliuyi j&=0x0f; 152*76af099aSliuyi K[i] = key[j]; 153*76af099aSliuyi j++; 154*76af099aSliuyi } 155*76af099aSliuyi 156*76af099aSliuyi j = 0; 157*76af099aSliuyi for(i=0; i<256; i++){ 158*76af099aSliuyi j = (j + S[i] + K[i]) % 256; 159*76af099aSliuyi temp = S[i]; 160*76af099aSliuyi S[i] = S[j]; 161*76af099aSliuyi S[j] = temp; 162*76af099aSliuyi } 163*76af099aSliuyi 164*76af099aSliuyi i = j = 0; 165*76af099aSliuyi for(x=0; x<len; x++){ 166*76af099aSliuyi i = (i+1) % 256; 167*76af099aSliuyi j = (j + S[i]) % 256; 168*76af099aSliuyi temp = S[i]; 169*76af099aSliuyi S[i] = S[j]; 170*76af099aSliuyi S[j] = temp; 171*76af099aSliuyi t = (S[i] + (S[j] % 256)) % 256; 172*76af099aSliuyi buf[x] = buf[x] ^ S[t]; 173*76af099aSliuyi } 174*76af099aSliuyi } 175*76af099aSliuyi 176*76af099aSliuyi void bch_encode(unsigned char* encode_in, unsigned char* encode_out) 177*76af099aSliuyi { 178*76af099aSliuyi UINT i,j; 179*76af099aSliuyi bool feed_back; 180*76af099aSliuyi UINT bch1=0; 181*76af099aSliuyi UINT bch2=0; 182*76af099aSliuyi UINT bch3=0; 183*76af099aSliuyi UINT bch4=0; 184*76af099aSliuyi 185*76af099aSliuyi for (i=0;i<515;i++) 186*76af099aSliuyi { 187*76af099aSliuyi for (j=0;j<8;j++) 188*76af099aSliuyi { 189*76af099aSliuyi feed_back = (bch1&1) ^ ((encode_in[i]>>j) & 1); 190*76af099aSliuyi bch1=((bch1>>1)|((bch2&1)*0x80000000))^(ggx1*feed_back); 191*76af099aSliuyi bch2=((bch2>>1)|((bch3&1)*0x80000000))^(ggx2*feed_back); 192*76af099aSliuyi bch3=((bch3>>1)|((bch4&1)*0x80000000))^(ggx3*feed_back); 193*76af099aSliuyi bch4=(((bch4>>1)^(ggx4*feed_back))) | (feed_back*0x80); 194*76af099aSliuyi } 195*76af099aSliuyi } 196*76af099aSliuyi 197*76af099aSliuyi //********Handle FF*********************** 198*76af099aSliuyi bch1 = ~(bch1 ^ 0xad6273b1); 199*76af099aSliuyi bch2 = ~(bch2 ^ 0x348393d2); 200*76af099aSliuyi bch3 = ~(bch3 ^ 0xe6ebed3c); 201*76af099aSliuyi bch4 = ~(bch4 ^ 0xc8); 202*76af099aSliuyi //********************************************* 203*76af099aSliuyi 204*76af099aSliuyi for (i=0;i<515;i++) 205*76af099aSliuyi encode_out[i] = encode_in[i]; 206*76af099aSliuyi encode_out[515] = bch1&0x000000ff; 207*76af099aSliuyi encode_out[516] = (bch1&0x0000ff00)>>8; 208*76af099aSliuyi encode_out[517] = (bch1&0x00ff0000)>>16; 209*76af099aSliuyi encode_out[518] = (bch1&0xff000000)>>24; 210*76af099aSliuyi encode_out[519] = bch2&0x000000ff; 211*76af099aSliuyi encode_out[520] = (bch2&0x0000ff00)>>8; 212*76af099aSliuyi encode_out[521] = (bch2&0x00ff0000)>>16; 213*76af099aSliuyi encode_out[522] = (bch2&0xff000000)>>24; 214*76af099aSliuyi encode_out[523] = bch3&0x000000ff; 215*76af099aSliuyi encode_out[524] = (bch3&0x0000ff00)>>8; 216*76af099aSliuyi encode_out[525] = (bch3&0x00ff0000)>>16; 217*76af099aSliuyi encode_out[526] = (bch3&0xff000000)>>24; 218*76af099aSliuyi encode_out[527] = bch4&0x000000ff; 219*76af099aSliuyi } 220*76af099aSliuyi 221*76af099aSliuyi #define poly16_CCITT 0x1021 /* crc-ccitt mask */ 222*76af099aSliuyi 223*76af099aSliuyi unsigned short CRC_Calculate(unsigned short crc, unsigned char ch) 224*76af099aSliuyi { 225*76af099aSliuyi UINT i; 226*76af099aSliuyi for(i=0x80; i!=0; i>>=1) 227*76af099aSliuyi { 228*76af099aSliuyi if((crc & 0x8000) != 0) 229*76af099aSliuyi { 230*76af099aSliuyi crc <<= 1; 231*76af099aSliuyi crc ^= poly16_CCITT; 232*76af099aSliuyi } 233*76af099aSliuyi else 234*76af099aSliuyi crc <<= 1; 235*76af099aSliuyi if((ch & i)!=0) 236*76af099aSliuyi crc ^= poly16_CCITT; 237*76af099aSliuyi } 238*76af099aSliuyi return crc; 239*76af099aSliuyi } 240*76af099aSliuyi unsigned short CRC_CCITT(unsigned char* p, UINT CalculateNumber) 241*76af099aSliuyi { 242*76af099aSliuyi unsigned short crc = 0xffff; 243*76af099aSliuyi while(CalculateNumber--) 244*76af099aSliuyi { 245*76af099aSliuyi crc = CRC_Calculate(crc, *p); 246*76af099aSliuyi p++; 247*76af099aSliuyi } 248*76af099aSliuyi return crc; 249*76af099aSliuyi } 250*76af099aSliuyi void gen_poly() 251*76af099aSliuyi { 252*76af099aSliuyi UINT gen_roots[nn + 1], gen_roots_true[nn + 1] ; // Roots of generator polynomial 253*76af099aSliuyi UINT i, j, Temp ; 254*76af099aSliuyi 255*76af099aSliuyi // Initialization of gen_roots 256*76af099aSliuyi for (i = 0; i <= nn; i++) 257*76af099aSliuyi { gen_roots_true[i] = 0; 258*76af099aSliuyi gen_roots[i] = 0; 259*76af099aSliuyi } 260*76af099aSliuyi 261*76af099aSliuyi // Cyclotomic cosets of gen_roots 262*76af099aSliuyi for (i = 1; i <= 2*tt ; i++) 263*76af099aSliuyi { 264*76af099aSliuyi for (j = 0; j < mm; j++) 265*76af099aSliuyi { 266*76af099aSliuyi Temp = ((1<<j)*i)%nn; 267*76af099aSliuyi gen_roots_true[Temp] = 1; 268*76af099aSliuyi } 269*76af099aSliuyi } 270*76af099aSliuyi rr = 0; // Count thenumber of parity check bits 271*76af099aSliuyi for (i = 0; i < nn; i++) 272*76af099aSliuyi { 273*76af099aSliuyi if (gen_roots_true[i] == 1) 274*76af099aSliuyi { 275*76af099aSliuyi rr++; 276*76af099aSliuyi gen_roots[rr] = i; 277*76af099aSliuyi } 278*76af099aSliuyi } 279*76af099aSliuyi // Compute generator polynomial based on its roots 280*76af099aSliuyi gg[0] = 2 ; // g(x) = (X + alpha) initially 281*76af099aSliuyi gg[1] = 1 ; 282*76af099aSliuyi for (i = 2; i <= rr; i++) 283*76af099aSliuyi { 284*76af099aSliuyi gg[i] = 1 ; 285*76af099aSliuyi for (j = i - 1; j > 0; j--) 286*76af099aSliuyi if (gg[j] != 0) 287*76af099aSliuyi gg[j] = gg[j-1]^ alpha_to[(index_of[gg[j]] + index_of[alpha_to[gen_roots[i]]]) % nn] ; 288*76af099aSliuyi else 289*76af099aSliuyi gg[j] = gg[j-1] ; 290*76af099aSliuyi gg[0] = alpha_to[(index_of[gg[0]] + index_of[alpha_to[gen_roots[i]]]) % nn] ; 291*76af099aSliuyi } 292*76af099aSliuyi 293*76af099aSliuyi ggx1 = gg[103] | (gg[102]<<1) | (gg[101]<<2) | (gg[100]<<3) | (gg[99]<<4) |(gg[98]<<5)| (gg[97]<<6)|(gg[96]<<7) 294*76af099aSliuyi | (gg[95]<<8) | (gg[94]<<9) | (gg[93]<<10) | (gg[92]<<11) |(gg[91]<<12)| (gg[90]<<13)|(gg[89]<<14) |(gg[88]<<15) 295*76af099aSliuyi | (gg[87]<<16) | (gg[86]<<17) | (gg[85]<<18) | (gg[84]<<19) | (gg[83]<<20) |(gg[82]<<21)| (gg[81]<<22)|(gg[80]<<23) 296*76af099aSliuyi | (gg[79]<<24) | (gg[78]<<25) | (gg[77]<<26) | (gg[76]<<27) |(gg[75]<<28)| (gg[74]<<29)|(gg[73]<<30) |(gg[72]<<31); 297*76af099aSliuyi ggx2 = gg[71] | (gg[70]<<1) | (gg[69]<<2) | (gg[68]<<3) | (gg[67]<<4) |(gg[66]<<5)| (gg[65]<<6)|(gg[64]<<7) 298*76af099aSliuyi | (gg[63]<<8) | (gg[62]<<9) | (gg[61]<<10) | (gg[60]<<11) |(gg[59]<<12)| (gg[58]<<13)|(gg[57]<<14) |(gg[56]<<15) 299*76af099aSliuyi | (gg[55]<<16) | (gg[54]<<17) | (gg[53]<<18) | (gg[52]<<19) | (gg[51]<<20) |(gg[50]<<21)| (gg[49]<<22)|(gg[48]<<23) 300*76af099aSliuyi | (gg[47]<<24) | (gg[46]<<25) | (gg[45]<<26) | (gg[44]<<27) |(gg[43]<<28)| (gg[42]<<29)|(gg[41]<<30) |(gg[40]<<31); 301*76af099aSliuyi ggx3 = gg[39] | (gg[38]<<1) | (gg[37]<<2) | (gg[36]<<3) | (gg[35]<<4) |(gg[34]<<5)| (gg[33]<<6)|(gg[32]<<7) 302*76af099aSliuyi | (gg[31]<<8) | (gg[30]<<9) | (gg[29]<<10) | (gg[28]<<11) |(gg[27]<<12)| (gg[26]<<13)|(gg[25]<<14) |(gg[24]<<15) 303*76af099aSliuyi | (gg[23]<<16) | (gg[22]<<17) | (gg[21]<<18) | (gg[20]<<19) | (gg[19]<<20) |(gg[18]<<21)| (gg[17]<<22)|(gg[16]<<23) 304*76af099aSliuyi | (gg[15]<<24) | (gg[14]<<25) | (gg[13]<<26) | (gg[12]<<27) |(gg[11]<<28)| (gg[10]<<29)|(gg[9]<<30) |(gg[8]<<31); 305*76af099aSliuyi ggx4 = gg[7] | (gg[6]<<1) | (gg[5]<<2) | (gg[4]<<3) | (gg[3]<<4) |(gg[2]<<5)| (gg[1]<<6); 306*76af099aSliuyi 307*76af099aSliuyi } 308*76af099aSliuyi 309*76af099aSliuyi void generate_gf() 310*76af099aSliuyi { 311*76af099aSliuyi UINT i; 312*76af099aSliuyi UINT mask ; // Register states 313*76af099aSliuyi 314*76af099aSliuyi // Primitive polynomials 315*76af099aSliuyi for (i = 1; i < mm; i++) 316*76af099aSliuyi p[i] = 0; 317*76af099aSliuyi p[0] = p[mm] = 1; 318*76af099aSliuyi if (mm == 2) p[1] = 1; 319*76af099aSliuyi else if (mm == 3) p[1] = 1; 320*76af099aSliuyi else if (mm == 4) p[1] = 1; 321*76af099aSliuyi else if (mm == 5) p[2] = 1; 322*76af099aSliuyi else if (mm == 6) p[1] = 1; 323*76af099aSliuyi else if (mm == 7) p[1] = 1; 324*76af099aSliuyi else if (mm == 8) p[4] = p[5] = p[6] = 1; 325*76af099aSliuyi else if (mm == 9) p[4] = 1; 326*76af099aSliuyi else if (mm == 10) p[3] = 1; 327*76af099aSliuyi else if (mm == 11) p[2] = 1; 328*76af099aSliuyi else if (mm == 12) p[3] = p[4] = p[7] = 1; 329*76af099aSliuyi else if (mm == 13) p[1] = p[2] = p[3] = p[5] = p[7] = p[8] = p[10] = 1; // 25AF 330*76af099aSliuyi else if (mm == 14) p[2] = p[4] = p[6] = p[7] = p[8] = 1; // 41D5 331*76af099aSliuyi else if (mm == 15) p[1] = 1; 332*76af099aSliuyi else if (mm == 16) p[2] = p[3] = p[5] = 1; 333*76af099aSliuyi else if (mm == 17) p[3] = 1; 334*76af099aSliuyi else if (mm == 18) p[7] = 1; 335*76af099aSliuyi else if (mm == 19) p[1] = p[5] = p[6] = 1; 336*76af099aSliuyi else if (mm == 20) p[3] = 1; 337*76af099aSliuyi // Galois field implementation with shift registers 338*76af099aSliuyi // Ref: L&C, Chapter 6.7, pp. 217 339*76af099aSliuyi mask = 1 ; 340*76af099aSliuyi alpha_to[mm] = 0 ; 341*76af099aSliuyi for (i = 0; i < mm; i++) 342*76af099aSliuyi { 343*76af099aSliuyi alpha_to[i] = mask ; 344*76af099aSliuyi index_of[alpha_to[i]] = i ; 345*76af099aSliuyi if (p[i] != 0) 346*76af099aSliuyi alpha_to[mm] ^= mask ; 347*76af099aSliuyi mask <<= 1 ; 348*76af099aSliuyi } 349*76af099aSliuyi 350*76af099aSliuyi index_of[alpha_to[mm]] = mm ; 351*76af099aSliuyi mask >>= 1 ; 352*76af099aSliuyi for (i = mm + 1; i < nn; i++) 353*76af099aSliuyi { 354*76af099aSliuyi if (alpha_to[i-1] >= mask) 355*76af099aSliuyi alpha_to[i] = alpha_to[mm] ^ ((alpha_to[i-1] ^ mask) << 1) ; 356*76af099aSliuyi else 357*76af099aSliuyi alpha_to[i] = alpha_to[i-1] << 1 ; 358*76af099aSliuyi 359*76af099aSliuyi index_of[alpha_to[i]] = i ; 360*76af099aSliuyi } 361*76af099aSliuyi index_of[0] = -1 ; 362*76af099aSliuyi }