Summary of FAT file system 3
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// ChkSum()
// Returns an unsigned byte checksum computed on an unsigned byte
// array. The array must be 11 bytes long and is assumed to contain
// a name stored in the format of a MS-DOS directory entry.
unsigned char ChkSum (unsigned char *pFcbName)
{
short FcbNameLen; unsigned char Sum;
Sum = 0;
for (FcbNameLen=11; FcbNameLen!=0; FcbNameLen--) {
// NOTE: The operation is an unsigned char rotate right Sum = ((Sum & 1) ? 0x80 : 0) + (Sum >> 1) + *pFcbName++;
}
return (Sum);
}
Below is a leader filename directory entries.
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