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Incorrect CRC32 values being computed???

Posted: Sat Dec 24, 2005 5:25 am
by Anonymous
I've been cataloging all my ROMs and have noticed that when I look at the CRC32 output from SNES9x 1.43 for a ROM, and then I check that same ROM with CRC32.exe and CheckCRC.exe or any other CRC32 checking program, they all give a different value than SNES9x is giving me (but all of the indepependent CRC checkers give the same value as each other.) Some ROMs SNES9x does give the correct value, but I'm finding that a great many of my ROMs are showing incorrect values when I look at their info through SNES9x. Is this problem something only I'm running into? I've tried it with 3 seperate computers, all with the same results from SNES9x and the various CRC32 checking programs. Can some people try checking like 10 of their ROMs and seeing the CRC value that SNES9x gives, then check those same ROM files with an independent CRC program. I've already spent so many darned hours copying over values to the little database I'm making, so I'd like to know if the values from SNES9x were correct. Also, why are they different so many times? Argh!

Here's an example:

ROM: Zoop (USA version 1.0).smc
SNES9x CRC32: 06F0E94C
CheckCRC.exe says: FCAE4EE4
CRC32.exe says: 0xFCAE4EE4

Posted: Sat Dec 24, 2005 8:34 am
by zones
Remove the copier's header before calculating with CRC32.exe and CheckCRC.exe.

Posted: Sat Dec 24, 2005 5:01 pm
by Nach
Snes9x computes the CRC32 of the ROM, not the file, big difference.

Since your standard tools don't understand what an SNES ROM is, they can't show you the ROM's CRC32.

If you want to know the CRC32 of an SNES ROM, you can use NSRT, uCON64, ZSNES, or Snes9x, and they are all correct.

Thanks!

Posted: Sun Dec 25, 2005 4:35 am
by Anonymous
Wonderful, now I understand. Thanks guys.