[ixp1200] Re: contents of ixp1200 digest

[Wong Kim Sing]

Hello Somu,

Thank a lot for your help.

-----Original Message-----
From: ixp1200-bounces at lists.cs.princeton.edu
[mailto:ixp1200-bounces at lists.cs.princeton.edu] On Behalf Of Somu Ghosh
Sent: Wednesday, June 15, 2005 8:48 PM
To: ixp1200 at lists.cs.princeton.edu
Subject: [ixp1200] Re: contents of ixp1200 digest

The IXP1200 is different from 2400 is three main ways.

1. The Rx/TX engine is totally different. So for migration you should
rewrite your code for send and rx. Framing code will be the same, so
64 quad words format still remain the same. All you need to do is
schedule receive and transmit engines. My suggestion would be to use
the default rx and tx that comes with 2400 and fit it into your module

2. Memory map is radically different. First of all the memory
calculations would have to be changed. For Eg, DRAM has addresses like
1000, 1004, 1008, or something like that. That is it is byte memory
and not word memory. So you would have to align yourself very clearly.
writing something to 1000 and 1001 as SRAM (i think they have chnaged
the name) addresses would not give you the same effect in SRAM
(ixp1200). Similar rule apply for SDRAM

3. Efficient Memory Route. You have the advantage of next neighbor and
higher scratch along with double DMA size. You may want to use these
features for additional performance boost, but if you are looking for
portability, you may want to skip this step.

All the best in your efforts.,

Love,
Somu
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