Chris_C

smallest simplest open source softcore

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I'm wanting to look at source code to aid learning and to help with some crazy ideas I have

 

requirements as the title...

 

but also can you have an array of components but each with slightly different (calculated)  properties say based on their index?

 

I'm guessing that picoblaze is a lot more complex than I need and even on the pro you'd be lucky to get a dozen packed onto even a pro?

 

for learning purposes it could even be a 4bit CPU!

 

so I'm not even talking practical softcores - rather the smallest simplest CPU thats one or two up from a Von neuman machine...

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PIcoBlaze is what you want. There is plenty of documentation on it.

 

But if you are scraping the bottom of the bucket there is a PIC 16F84 in Verilog on OpenCores. It is all in once source file with a truck-load of comments. 

My little I2C controller is almost a CPU, just without an ALU (loads, stores, tests, input, output, jumps, branches) - http://hamsterworks.co.nz/mediawiki/images/9/90/I3c2.vhd

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how dare you knock the 16F84 its the biz ! B)  but seriously for a mo... thats way overkill for what I meant (its actually not that simple a cpu really!) on the other hand

 

I've already designed a 4 function 4 bit ALU in logisim last month... for fun! no really...

 

anyhow that I2C controller is just the thing dead simple, and you know what half way through your book and ten mins looking at that I2C processor and I can see how "linear" processing concepts can be performed instead by a state machine and it makes sense now how/why opengl for example used to be strictly a state machine...

 

thanks for suggesting your I2C, add 2-4 registers and a simple ALU and you could have a great tutorial....

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He wanted something so simple he could understand easily. It doesn't get much simpler than a state machine, you can have a simple CPU with 10 or so instructions in a state machine that anyone can understand and then expand on.

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