RE: [ethmac] magic number

["Illan Glasner" <iglasner@zumanetworks.com>]

24-Apr-01

   Hi,

	Assumign you reffer to the CRC magic number than the answer is
yes regardless of the data once you append the crc inverted and roatated
to the end of the packet and pass it again through crc checker the
result will always be the same.

two thing 

1. if you forget to invert-rotate the result will always be 0 and this
is actually the reson for the invert-rotate.

2. a more intresting thing is what do you do if the data is let say come
in 8 bit alignment but you use a 32 bit data bus and therefore 32 bit
crc equation. just something to think about.

have a nice day

   Illan


-----Original Message-----
From: 97024 Hendra Gunawan [mailto:hendrag01@students.ee.itb.ac.id]
Sent: Monday, April 23, 2001 6:38 PM
To: ethmac@opencores.org
Subject: [ethmac] magic number




hi'

anybody can tell me, where the magic numbers are from? is it right for
all
data  conditions?