10 Nov
2007
10 Nov
'07
2:32 p.m.
On Saturday 10 November 2007 16:33, dwight elvey wrote:
Nope, it was definitely more complicated than that. I know it's been quite
some time since I saw that code, but they were doing all sorts of shifting
and adding and whatnot, and I distinctly recall "polynomial" (?) being
mentioned in there somewhere.
From:
rtellason at verizon.net
---snip---
Unfortunately, I have *no* idea how one would
make an eprom have the
appropriate CRC results. I suspect that one of the important details
would be the exact polynomial used to generate the CRC in the first
place, and I don't have that handy at the moment, have to figure out just
where the heck that is...
But any suggestions as to where I might research this further would be
appreciated.
Hi
It is most likely a simple checksum and not a crc. Still, making a crc come out to zero is not hard. It
is about the same as a
checksum resulting in zero. If it was doing a 16 bit crc, it would need 2
bytes to be the check bits.
Right. So you'd need some way to give the assembler instructions to look at
its own output? Or look at it, figure out the right value somehow (and how
I'm not at all clear about), and stuff that value in there at the end of
your code, then? This is where I got confused, I think.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin