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[ts-7000] Re: NAND flash based vs NOR flash based

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Subject: [ts-7000] Re: NAND flash based vs NOR flash based
From: "twhk2007" <>
Date: Thu, 18 Jan 2007 05:00:01 -0000
Hi Curtis and other members,

>Curtis wrote 
>You may look into downloading the Cirrus Logic GCC compiler with 
>Maverick Crunch enabled. This could double the speed of your code. 
>The only problem is the TS Linux kernel does not support Maverick 
>Crunch. So it isn't initialized and you can't have more than one 
>task using it, as the Crunch registers are not preserved between 
>tasks. You will also have trouble linking to libraries that were 
>not compiled with it.
>Some people have ported Linux 2.6 kernels that should support 
>Crunch.

  I am new to the GCC complier. From the GCC 4.1.1 manual 
(http://gcc.gnu.org/onlinedocs/), I can only see the -mcpu option 
for EP9312. How about EP9302 and other EP93xx ? Is there anyone used 
the hardware floating point for EP9302 ? Does the current GCC 
complier (or other version) support the Maverick floating point co-
processor in EP9302 ? 

Many thanks !
James 

--- In  "twhk2007" <> wrote:
>
> Thanks for your advice !
> 
> --- In  Curtis Monroe <curtis@> wrote:
> >
> > On January 17, 2007 08:55 am, Christopher Friedt wrote:
> > > Hi James,
> > > 
> > > Neither of these boards will execute any code from flash as 
> opposed to 
> > > ram, that would hinder the processor drastically. I don't even 
> think the 
> > > processor supports program addressing in flash-based devices.
> > 
> > Technically NOR flash can execute code in-place (XIP). See 
article:
> > http://www.edn.com/article-partner/CA6257144.html
> > 
> > Nand Flash cannot XIP. It works more like a hard drive loading 
and 
> storing 
> > sectors. Nand also need to correct errors that occur in each 
pages
> (ECC), NOR 
> > doesn't.
> > 
> > I'm not sure if the TS-7200 with NOR flash uses XIP. But that 
> should not 
> > really matter. The EP9302 (or EP9301 on earlier TS-7200 boards) 
> has enough 
> > cache to store most of your critical code. Its the speed of the 
> cache that 
> > will be the biggest factor. 
> > 
> > So Nor and Nand will only make a difference in the speed of 
> loading code to 
> > your cache. Once the code is in the cache it will go at top 
speed!
> >  
> > 
> > > 
> > > You're looking at nearly the exact same execution time. There 
> would only 
> > > be a very slight difference if one board had 32 MB sdram and 
one 
> had 64 
> > > MB sdram, since a board w/ 64 MB sdram has a dis-contiguous 
ram 
> layout 
> > > and thus would require a very very slight overhead in page 
table 
> > > translation from virtual addressing -> physical addressing.
> > 
> > The 32MB sdram is discontinuous too. The EP9302 stores data and 
> code in the 
> > cache indexed by its virtual address, not its physical 
addresses. 
> So once the 
> > code is in the cache it does not need address translation to get 
> fetched 
> > again. So address translation will not slow it down.
> >   
> > 
> > > 
> > > ~/Chris
> > > 
> > > twhk2007 wrote:
> > > > Hello all !
> > > > 
> > > > TS-7200 uses NOR flash while TS-7260 uses NAND flash. I know 
> that the
> > > > read time for NOR flash is faster than that of NAND flash. I 
> will use 
> > > > the board to do a lot of floating point calculations. Could 
> you anyone 
> > 
> > You may look into downloading the Cirrus Logic GCC compiler with 
> Maverick 
> > Crunch enabled. This could double the speed of your code. The 
only 
> problem is 
> > the TS Linux kernel does not support Maverick Crunch. So it 
isn't 
> initialized 
> > and you can't have more than one task using it, as the Crunch 
> registers are 
> > not preserved between tasks. You will also have trouble linking 
to 
> libraries 
> > that were not compiled with it.
> > 
> > Some people have ported Linux 2.6 kernels that should support 
> Crunch.
> > 
> > -Curtis.
> > 
> > 
> > > > on the execution speed for these two boards ? Some people 
> mention that 
> > > > the code in NAND flash will be transfered to SDRAM during 
> excution, so 
> > > > the excution speed of a NAND flash-based board can be faster 
> than NOR 
> > > > flash-based board. Is this true for TS-7260 ?
> > > > 
> > > > Best regards,
> > > > James
> > > > 
> > > > 
> > >
> >
>




 
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