06-21-2003, 09:10 PM
TO ANTONI:
Yes, the CRC calculation is probably one of the most popular uses of the XOR. The LRC (Longitudinal Redundancy Character or Check) used on some mainframe magnetic tape units, is a simpler computation that also uses the XOR, but is a less robust error checking technique than the CRC.
If anyone is interested, I have the "C" code for generating the identical CRC used by PKZIP. I didn't concieve it, but I fixed it to work.
x EQV y
EQV stands for Equivalent, meaning it tests if the expressions X and Y are the "same", i.e., either both true or both false.
I honestly have never had an opportunity to use it.
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TO AGAMEMNUS:
Regarding the name of XOR, i.e., exclusive-or. The story that I heard years ago is that a regular OR is an inclusive-or. If either of the bits is on, then the resultant bit will be inclusively on. But, for an XOR, if the bits are both on, then the resultant bit will be exclusively off. OK, not the best definition. Note that in some languages an XOR is written as EOR.
*****
Yes, the CRC calculation is probably one of the most popular uses of the XOR. The LRC (Longitudinal Redundancy Character or Check) used on some mainframe magnetic tape units, is a simpler computation that also uses the XOR, but is a less robust error checking technique than the CRC.
If anyone is interested, I have the "C" code for generating the identical CRC used by PKZIP. I didn't concieve it, but I fixed it to work.
x EQV y
EQV stands for Equivalent, meaning it tests if the expressions X and Y are the "same", i.e., either both true or both false.
I honestly have never had an opportunity to use it.
-----------------------------------------------------------------------------------
TO AGAMEMNUS:
Regarding the name of XOR, i.e., exclusive-or. The story that I heard years ago is that a regular OR is an inclusive-or. If either of the bits is on, then the resultant bit will be inclusively on. But, for an XOR, if the bits are both on, then the resultant bit will be exclusively off. OK, not the best definition. Note that in some languages an XOR is written as EOR.
*****