[Milkymist-devel] Mic032

[Sébastien Bourdeauducq]

Hi,

On Friday 28 August 2009 00:29:23 you wrote:
> I saw your Milkymist project when I was looking for information Mic32 ports
> for Xilinx. Very cool ;-)

Thanks :)

> One thing that I was wondering was why you were planning on moving from
> Mico32 to the open source MicroBlaze project. We've been pretty happy with
> Mico32 and MSB, but have had nothing but bad experiences with MicroBlaze
> and EDK (primarily the latter).

Actually, the first versions of Milkymist were using AEMB, which only shares 
its instruction set with Microblaze. It's not a drop-in replacement - the bus 
is different, and it also has 2 hardware threads.

Milkymist moved to Mico32 last month, for technical (performance) and software 
portability/simplicity reasons (see mailing list archives for more details).

But I think that AEMB is slightly more "open source friendly" than Mico32 
(LGPL license and developed by an individual, not a big company), and that's 
why I'm looking forward to use it again when it's technically possible to do 
so.

Milkymist does not use MSB nor EDK, it's written entirely in Verilog without 
any special preprocessor or source code generator. The build scripts only run 
the synthesizer.

Switching between AEMB and Mico32 only requires patching ~150 lines of code 
altogether, counting the firmware, the Verilog code (excluding the CPU design 
of course) and the build scripts. The system then builds and works the same 
way, regardless of the processor.

Regards,
Sébastien