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Message
From: Mohit Sindhwani<mohits@o...>
Date: Wed Sep 28 17:55:59 CEST 2005
Subject: [openrisc] OpenRisc vs Leon
Balint Cristian wrote:
> On Wednesday 28 September 2005 16:05, Bill Cox wrote:
>
>> Hi.
>>
>> I get questions now and then as to which open-source processor to
>> recommend. I generally recommend the OpenRisc processor, but yesterday
>> EETimes ran an article about TSCM promoting Leon.
>>
>> The OpenRisc processor seems to have a vibrant user group, and multiple
>> open-source tool chains and operating systems. The Leon site doesn't
>> even have a user forum. However, being "Sparc compatible" seems like a
>> big draw.
>>
>
> It has a "forum", there are 3 mailinglist, and well maintained by Jiri Gaisler the leadear/founder of the project.
> Unfortunatley Leon have comercial parts e.g the FPU and the smp variant, and some ASIC assistance stuff.
>
>
>> What arguments would you guys put forward for OpenRisc vs Leon?
>>
>
> OpenRISC is a concept from the scratch with completly free ideology, Leon is a sparcv7 compliance.
> What if maybe sparc (TM) will one day charge for it's IP, who knows ? Just like MIPS do it right now.
>
>
> As performance and other analysis there is a comparasion between Leon2/OpenRISC/Microblaze
> http://www.gaisler.com/doc/Evaluation_of_synthesizable_CPU_cores.pdf
>
>
>
One of the things about the OpenRISC that attracts me is the ability to
add custom instructions to the ISA. I think that offers significant
possibilities. That is something that both Leon and MicroBlaze seem to
lack. Specially on FPGA fabric, Custom Instructions are really good to
have :)
On the other hand, when it comes to adding Custom Instructions, I feel
that the Altera NIOS has the most streamlined interface for the job.
It's easy to understand and very easy to use - even a software engineer
(me included) who has flirted with hardware can add & use simple custom
instructions.
Cheers
Mohit.
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