S3C2440中ECC校验算法实现

/* 文件名：EccTest.c 功 能：对2048个字节进行ECC检验 作 者：吕氏春秋8266 v1.0 函 数：CreatEccTabe 生成0~256数值的ECC码， 其中bit7=0,bit6=行检验码,bit5=p4_0,bit4=p4_1,bit3=p2_0,bit2=p2_1,bit1=p1_0,bit0=p1_1 */ //用VC6编译通过 #include "stdio.h" unsigned int BIT0(unsigned char x) { return (x&1)>>0;} unsigned int BIT1(unsigned char x) { return (x&2)>>1;} unsigned int BIT2(unsigned char x) { return (x&4)>>2;} unsigned int BIT3(unsigned char x) { return (x&8)>>3;} unsigned int BIT4(unsigned char x) { return (x&16)>>4;} unsigned int BIT5(unsigned char x) { return (x&32)>>5;} unsigned int BIT6(unsigned char x) { return (x&64)>>6;} unsigned int BIT7(unsigned char x) { return (x&128)>>7;} //生成256个字节的Ecc码 void CreatEccTabe(unsigned char *Ecc_Table) { unsigned int i; unsigned char xData; for (i=0;i<256;i++) { xData=0; if(BIT1(i)^BIT3(i)^BIT5(i)^BIT7(i)) {xData|=0x1; } //bit0 P1_1 if(BIT0(i)^BIT2(i)^BIT4(i)^BIT6(i)) {xData|=0x2; } //bit1 P1_0 if(BIT2(i)^BIT3(i)^BIT6(i)^BIT7(i)) {xData|=0x4; } //bit2 P2_1 if(BIT0(i)^BIT1(i)^BIT4(i)^BIT5(i)) {xData|=0x8; } //bit3 P2_0 if(BIT4(i)^BIT5(i)^BIT6(i)^BIT7(i)) {xData|=0x10;} //bit4 P4_1 if(BIT0(i)^BIT1(i)^BIT2(i)^BIT3(i)) {xData|=0x20;} //bit5 P4_0 if(BIT0(i)^BIT1(i)^BIT2(i)^BIT3(i)^BIT4(i)^BIT5(i)^BIT6(i)^BIT7(i)) //bit6 { xData|=0x40; } Ecc_Table[i]=xData; } } /* static const char Ecc_Table[256] = { 0x00,0x55,0x56,0x03,0x59,0x0C,0x0F,0x5A,0x5A,0x0F,0x0C,0x59,0x03,0x56,0x55,0x00, 0x65,0x30,0x33,0x66,0x3C,0x69,0x6A,0x3F,0x3F,0x6A,0x69,0x3C,0x66,0x33,0x30,0x65, 0x66,0x33,0x30,0x65,0x3F,0x6A,0x69,0x3C,0x3C,0x69,0x6A,0x3F,0x65,0x30,0x33,0x66, 0x03,0x56,0x55,0x00,0x5A,0x0F,0x0C,0x59,0x59,0x0C,0x0F,0x5A,0x00,0x55,0x56,0x03, 0x69,0x3C,0x3F,0x6A,0x30,0x65,0x66,0x33,0x33,0x66,0x65,0x30,0x6A,0x3F,0x3C,0x69, 0x0C,0x59,0x5A,0x0F,0x55,0x00,0x03,0x56,0x56,0x03,0x00,0x55,0x0F,0x5A,0x59,0x0C, 0x0F,0x5A,0x59,0x0C,0x56,0x03,0x00,0x55,0x55,0x00,0x03,0x56,0x0C,0x59,0x5A,0x0F, 0x6A,0x3F,0x3C,0x69,0x33,0x66,0x65,0x30,0x30,0x65,0x66,0x33,0x69,0x3C,0x3F,0x6A, 0x6A,0x3F,0x3C,0x69,0x33,0x66,0x65,0x30,0x30,0x65,0x66,0x33,0x69,0x3C,0x3F,0x6A, 0x0F,0x5A,0x59,0x0C,0x56,0x03,0x00,0x55,0x55,0x00,0x03,0x56,0x0C,0x59,0x5A,0x0F, 0x0C,0x59,0x5A,0x0F,0x55,0x00,0x03,0x56,0x56,0x03,0x00,0x55,0x0F,0x5A,0x59,0x0C, 0x69,0x3C,0x3F,0x6A,0x30,0x65,0x66,0x33,0x33,0x66,0x65,0x30,0x6A,0x3F,0x3C,0x69, 0x03,0x56,0x55,0x00,0x5A,0x0F,0x0C,0x59,0x59,0x0C,0x0F,0x5A,0x00,0x55,0x56,0x03, 0x66,0x33,0x30,0x65,0x3F,0x6A,0x69,0x3C,0x3C,0x69,0x6A,0x3F,0x65,0x30,0x33,0x66, 0x65,0x30,0x33,0x66,0x3C,0x69,0x6A,0x3F,0x3F,0x6A,0x69,0x3C,0x66,0x33,0x30,0x65, 0x00,0x55,0x56,0x03,0x59,0x0C,0x0F,0x5A,0x5A,0x0F,0x0C,0x59,0x03,0x56,0x55,0x00 }; */ /* Ecc_Make生成2048个字节的ECC校验码，其中，list用来保存列检验码，row0,row1保存行检验码 bit10 bit9 bit8 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 row0为p8192_0 p4096_0 p2048_0 p1024_0 p512_0 p256_0 p128_0 p64_0 p32_0 p16_0 p8_0 row1为p8192_1 p4096_1 p2048_1 p1024_1 p512_1 p256_1 p128_1 p64_1 p32_1 p16_1 p8_1 说 明：s3c2440中ECC表如下： BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0 MECCN_0 P64_0 P64_1 P32_0 P32_1 P16_0 P16_1 P8_0 P8_1 MECCN_1 P1024_0 P1024_1 P512_0 P512_1 P256_0 P256_1 P128_0 P128_1 MECCN_2 P4_0 P4_1 P2_0 P2_1 P1_0 P1_1 P2048_0 P2048_1 MECCN_3 P8192_0 P8192_1 P4096_0 P4096_1 - - - - */ void Ecc_Make(unsigned char *pData,unsigned char *Ecc_Table,unsigned long *EccData0,unsigned long *EccData1) { unsigned int i,j; unsigned char byte=0,list=0; unsigned long row0=0,row1=0,temp=0 ; for(i=0;i<2048;i++) { j=pData[i]; //得到要检验的数值 byte=Ecc_Table[j]; //查表得到ECC结果 list^=(byte&0x3f); //得到列检验码 if(byte&0x40) //判断第6位为行检验码 { row0^=((~i)&0x7ff); row1^=(i&0x7ff); } } //将得到的校验码按s3c2440要求的格式排列 temp|=(row0&1)<<1 ; //p8_1->temp[0] temp|=(row1&1)<<0 ; //p8_0->temp[1] temp|=(row0&2)<<2 ; //p16_1->temp[2] temp|=(row1&2)<<1 ; //p16_0->temp[3] temp|=(row0&4)<<3 ; //p32_1->temp[4] temp|=(row1&4)<<2 ; //p32_0->temp[5] temp|=(row0&8)<<4 ; //p64_1->temp[6] temp|=(row1&8)<<3 ; //p64_0->temp[7] temp|=(row0&16)<<5 ; //p128_1->temp[8] temp|=(row1&16)<<4 ; //p128_0->temp[9] temp|=(row0&32)<<6 ; //p256_1->temp[10] temp|=(row1&32)<<5 ; //p256_0->temp[11] temp|=(row0&64)<<7 ; //p512_1->temp[12] temp|=(row1&64)<<6 ; //p512_0->temp[13] temp|=(row0&128)<<8 ; //p1024_1->temp[14] temp|=(row1&128)<<7 ; //p1024_0->temp[15] *EccData0=temp ; temp=0; temp=list<<2; //将列校验码加入到EccData1[2~7] temp|=(row0&256)>>7 ; //p2048_1->temp[0] temp|=(row1&256)>>8 ; //p2048_0->temp[1] temp|=(row0&512)<<4 ; //p4096_1->temp[12] temp|=(row1&512)<<3 ; //p4096_0->temp[13] temp|=(row0&1024)<<5 ; //p8192_1->temp[14] temp|=(row1&1024)<<4 ; //p8192_0->temp[15] *EccData1=temp; return; } /*得取ECC码中1的个数*/ unsigned long EccCheckNumber(unsigned long Err_Data0,unsigned long Err_Data1) { unsigned long i,number=0; for(i=0;i<16;i++) { if(((Err_Data0>>i)&0x1)==1) number++; if(((Err_Data1>>i)&0x1)==1) number++; } return number; } /*判断数据是否正确，返回值0，正确，1，有一位错误，可纠正 2，校验码错误3.错误，*/ unsigned long ErrCheckEcc(unsigned long *Ecc_data0,unsigned long *Ecc_data1, unsigned long *Ecc_data2,unsigned long *Ecc_data3) { unsigned long Err_Data0,Err_Data1,Err_number,Ecc_Flag=0; Err_Data0=(*Ecc_data0)^(*Ecc_data2); Err_Data1=(*Ecc_data1)^(*Ecc_data3); printf("Ecc Err_Data is 0x%x%x\n",Err_Data1,Err_Data0); Err_number=EccCheckNumber(Err_Data0,Err_Data1); if(Err_number==0) return 0; if(Err_number==14) //一位数据错误，可修正 { Ecc_Flag|=0x1; //错误码Ecc_Flag[1~0] Ecc_Flag|=(Err_Data1&0x4)>>0; //p1_1->Ecc_Flag[2] Ecc_Flag|=(Err_Data1&0x10)>>1; //p2_1->Ecc_Flag[3] Ecc_Flag|=(Err_Data1&0x40)>>2; //p3_1->Ecc_Flag[4] Ecc_Flag|=(Err_Data0&0x1)<<5; //p8_1->Ecc_Flag[5] Ecc_Flag|=(Err_Data0&0x4)<<4; //p16_1->Ecc_Flag[6] Ecc_Flag|=(Err_Data0&0x10)<<3; //p32_1->Ecc_Flag[7] Ecc_Flag|=(Err_Data0&0x40)<<2; //p64_1->Ecc_Flag[8] Ecc_Flag|=(Err_Data0&0x100)<<1; //p128_1->Ecc_Flag[9] Ecc_Flag|=(Err_Data0&0x400)>>0; //p256_1->Ecc_Flag[10] Ecc_Flag|=(Err_Data0&0x1000)>>1; //p512_1->Ecc_Flag[11] Ecc_Flag|=(Err_Data0&0x4000)>>2; //p1024_1->Ecc_Flag[12] Ecc_Flag|=(Err_Data1&0x1)<<13; //p2048_1->Ecc_Flag[13] Ecc_Flag|=(Err_Data1&0x1000)<<2; //p4096_1->Ecc_Flag[14] Ecc_Flag|=(Err_Data1&0x4000)<<1; //p8192_1->Ecc_Flag[15] return Ecc_Flag; } if(Err_number==1) return 2; //校验码错误 return 3; //超过一位或其它错误，无法修正 }