I use "Ctrl-R" to reply, and the name of the sender and TechToolsList are both set up as the reply To:, does this not work for everyone? I have tried to get my web site host to update their mail list program, but not a lot of luck...perhaps this week. As far as starting with FFFFFFF, is there a simple test I can do to find out one way or the other? I can fill a section of RAM with either FF or 00 and then run the signature on it...would that help? I do know that when I last looked at this that if I did a signature on a single byte the signature was the same as the data in the byte, so if the data was "AE" then the signature would be "00AE". I can send you known files and signatures for same, I'd need to get that info tomorrow though I don't have it at home. The signatures for Asteroids Eproms (RV2?) are: F1 - 53C9, E1 - 3D7A, C1 - 232F, NP3 - CBED though...I can send you those files if you don't have them... John :-#)# At 02:47 PM 06/05/2002 -0700, Zonn wrote:
I don't have a 9010a to verify the results, but I can write that fairly easily.
You left out a couple of things though.
What is the initial value of the CRC register (0000 or FFFF -- I assume it is 16 bits), and are the results inverted?
For example: CRC32 starts with an FFFFFFFF and inverts the results.
Starting with an FFFF allows leading zeros to be counted as part of the CRC, if you start with 0000, leading zeros will be ignored. Inverting the results has some advantages, but I don't remember what they were. But I guess it depends on how the designers of the 9010a did things.
Ideally you can answer the above questions and give me a file, or two, with known signatures, and I should be able to whip up a utility shortly.
-Zonn
BTW: It sure is a pain to respond to the list, I have to manually type "ThechToolsList@flippers.com", shouldn't there be an easier way? :^)
On Mon, 06 May 2002 14:02:30 -0700, John Robertson <jrr@flippers.com> wrote:
What we need is for some bright person to write a simple utility that converts data files to signatures. The signature formula is fairly simple and if combined with Bill Ung's ROMSUM would be a nice tool for our package. If you don't know ROMSUM it is a dos utility that will give a checksum listing plus the ROM size for a single or group of files...
The Signature process is a CRC process that uses the following feedback equation: X(to the 16th) + X(to the 12th) + X(to the 9th) +X(to the 7th) + 1 or P(X) = X(15th) + X(9th) + X(7th) +X(4th) + 1
So who wants to make a simple (not for me!) binary program that allows one to input a file and outputs it's signature?
John :-#)#
At 09:11 AM 06/05/2002 -0400, Kev wrote:
Anyone written any test scripts for these or at the very least have some checksum signatures?
Thanks, Kev