Re: [ECOS] Re: Bug in crc32 routine?

[Gary Thomas <gthomas at ecoscentric dot com>]

On Fri, 2002-10-11 at 06:00, Andrew Lunn wrote:
> I checked around and found a few more CRC calculations. In summary
> 
> 1) zlib
> 2) jffs2
> 3) gdb stubs
> 4) cygmon
> 5) ks32c5000 net driver
> 6) Redboot - already using cyg_crc32()
> 
> cygmon and gdb stubs i've left alone. The code is not particularly
> well commented.
> 
> jffs2 uses the same algorithm as cyg_crc32.
> 
> ks32c5000 wants the Ethernet FCS algorithm. 
> zlib uses an algorithm which happens to be the FCS algorithm :-)
> 
> So, what i've done is left cyg_crc32 alone and added a new one,
> cyg_ether_crc32. Another coincidence, is that it appears to use the
> same table of coefficients as cyg_crc32. The only difference is that
> it does some XORs at the beginning and the end. jffs2 and zlib need to
> be able to run the CRC over multiple buffers, so i've added support
> for this as well and some tests.
> 
> Redboot should not be affected in any way. I've removed the code from
> zlib, jffs2 and the ks32c5000 net driver. Unfortunately, i don't have
> the required hardware to test all this properly. It all compiles
> cleanly. The zlib tests run correctly. Also the normal jffs2 test
> passes. I hacked around with the jffs2 romfileio1 test on linux. It
> correctly recognizes the filesystem, but fails some of the mkdir and
> rename tests. This could be something to do with it running with a
> ramfs not romfs?
> 
> What i would like is some volunteers to run the following test:
> 
> 1) redboot flash CRC still work OK
> 2) redboot support for gzip images still works OK
> 3) Somebody with a Compaq Ipaq test that jffs2 still works OK
> 4) Somebody with a snds with a ks32c5000 test its still OK
> 
> Here is the patch. Once i get feedback on these i will commit the
> patch.

I tested 1,2,3 with good results.  I can't try 4, but I'd say go ahead
and commit the patch.  If there is a problem with 4, it can be addressed
later.

-- 
------------------------------------------------------------
Gary Thomas                  |
eCosCentric, Ltd.            |  
+1 (970) 229-1963            |  eCos & RedBoot experts
gthomas@ecoscentric.com      |
http://www.ecoscentric.com/  |
------------------------------------------------------------