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#include <stdio.h>
unsigned short CalculateCRC( unsigned char *buf, short num );
void shortCRC( void );
void searchID_CRC( void );
void MFM512_CRC( void );
void MFM256_CRC( void );
void searchID_CRC2( void );
void MFM512_CRC2( void );
void MFM256_CRC2( void );
void shortCRC2( void );
/******** main ***************/
void main( void )
{
// shortCRC();
searchID_CRC();
// MFM512_CRC();
// MFM256_CRC();
// searchID_CRC2();
// MFM512_CRC2();
// MFM256_CRC2();
// shortCRC2();
}
/****************************/
void shortCRC( void )
// To test crc for short run of data.
{
char msg[32];
unsigned short crc;
*(msg+0)= 0x02;
*(msg+1)= 0x00;
*(msg+2)= 0x03;
*(msg+3)= 0x02;
*(msg+4)= 0x41;
*(msg+5)= 0x65;
crc = CalculateCRC( (unsigned char*)(msg+0), 6 );
printf(" crc= %4x \n",crc );
}
/*************************/
void searchID_CRC( void )
// To search for init value for ID data.
{ // The answer is 0x00377500.
char msg[32];
short i,j;
unsigned short *pt;
unsigned short crc;
pt = (unsigned short*)msg;
*(msg+2)= 0x02;
*(msg+3)= 0x00;
*(msg+4)= 0x03;
*(msg+5)= 0x02;
*(msg+6)= 0x41;
*(msg+7)= 0x65;
for( i=0x0000; ; i++)
{
*pt = i;
if( i % 256 == 0 )
printf ("%4x\n",i);
crc = CalculateCRC( (unsigned char*)msg, 8 );
if ( crc == 0 )
break;
}
printf("found! %4x CRC(forID)=%4x \n", i, crc);
}
/******************************/
void MFM512_CRC( void )
// To search for init value for
// MFM-disk 512 data.
{ // The answer is 0x00377000;
char msg[600];
short i,j;
unsigned short *pt, *pt2;
unsigned short crc;
pt = (unsigned short*)msg;
for( i=0 ; i< 512; i++ )
*(msg+i+2) = 0xf6;
pt2 = (unsigned short*)(msg+2+512);
*pt2 = 0x2bf6; // given CRC value
for( i=0x2000; ; i++)
{
*pt = i;
if( i % 256 == 0 )
printf ("%4x\n",i);
crc = CalculateCRC( (unsigned char*)msg, 512+4 );
if ( crc == 0 )
break;
}
printf("found! %4x CRC(forMFM512)=%4x \n", i, crc);
}
/**************************/
void MFM256_CRC( void )
// To search for init value for
// MFM-disk 256 data.
{ // The answer is 0x00377000.
char msg[300];
short i,j;
unsigned short *pt, *pt2;
unsigned short crc;
pt = (unsigned short*)msg;
for( i=0 ; i< 256; i++ )
*(msg+i+2) = 0x21;
pt2 = (unsigned short*)(msg+2+256);
*pt2 = 0x84ed; // given CRC value
for( i=0x0000; ; i++)
{
*pt = i;
if( i % 256 == 0 )
printf ("%4x\n",i);
crc = CalculateCRC( (unsigned char*)msg, 256+4 );
if ( crc == 0 )
break;
}
printf("found! %4x CRC(forMFM256)=%4x \n", i, crc );
}
/*************************/
void searchID_CRC2( void )
// To search for init value for
// ID data including IAM.
{ // The answer is 0x0084CF00.
char msg[32];
short i,start;
unsigned short *pt;
unsigned short crc;
start=0;
pt = (unsigned short*)(msg+start);
*(msg+2)= 0xA1;
*(msg+3)= 0xA1;
*(msg+4)= 0xA1;
*(msg+5)= 0xFE;
*(msg+6)= 0x02;
*(msg+7)= 0x00;
*(msg+8)= 0x03;
*(msg+9)= 0x02;
*(msg+10)= 0x41;
*(msg+11)= 0x65;
for( i=0x0000; i<= 0xffff; i++)
{
*pt = i;
if( i % 256 == 0 )
printf ("%4x\n",i);
crc = CalculateCRC( (unsigned char*)(msg+start), 12-start );
if ( crc == 0 )
break;
}
printf("found! %4x CRC(forID)=%4x \n", i, crc);
}
/******************************/
void MFM512_CRC2( void )
// To search for init value for MFM-disk
// 512 data including IAM.
{ // The answer is 0x0084CF00.
char msg[600];
short i,j;
unsigned short *pt, *pt2;
unsigned short crc;
pt = (unsigned short*)msg;
*(pt+1) = 0xA1A1;
*(pt+2) = 0xA1FB;
for( i=0 ; i< 512; i++ )
*(msg+i+6) = 0xF6;
pt2 = (unsigned short*)(msg+6+512);
*pt2 = 0x2BF6; // given CRC value
for( i=0x7000; ; i++)
{
*pt = i;
if( i % 256 == 0 )
printf ("%4x\n",i);
crc = CalculateCRC( (unsigned char*)msg, 512+8 );
if ( crc == 0 )
break;
}
printf("found! %4x CRC(forMFM512)=%4x \n", i, crc);
}
/**************************/
void MFM256_CRC2( void )
// To search for init value for MFM-disk
// 256 data including IAM.
{ // The answer is 0x0084CF00.
char msg[300];
short i,j;
unsigned short *pt, *pt2;
unsigned short crc;
pt = (unsigned short*)msg;
*(pt+1) = 0xA1A1;
*(pt+2) = 0xA1FB;
for( i=0 ; i< 256; i++ )
*(msg+i+6) = 0x21;
pt2 = (unsigned short*)(msg+6+256);
*pt2 = 0x84ed; // given CRC value
for( i=0x6000; ; i++)
{
*pt = i;
if( i % 256 == 0 )
printf ("%4x\n",i);
crc = CalculateCRC( (unsigned char*)msg, 256+8 );
if ( crc == 0 )
break;
}
printf("found! %4x CRC(forMFM256)=%4x \n", i, crc );
}
/****************************/
void shortCRC2( void )
// To test crc for short run
// of data including IAM.
{
char msg[32];
unsigned short crc;
*(msg+0)= 0x84;
*(msg+1)= 0xCF;
*(msg+2)= 0xA1;
*(msg+3)= 0xA1;
*(msg+4)= 0xA1;
*(msg+5)= 0xFE;
*(msg+6)= 0x02;
*(msg+7)= 0x00;
*(msg+8)= 0x03;
*(msg+9)= 0x02;
*(msg+10)= 0x41;
*(msg+11)= 0x65;
crc = CalculateCRC( (unsigned char*)(msg+0), 12 );
printf(" crc= %4x \n",crc );
}
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