
Show HN: R8 Processor - ruchira66
http://www.hasaranga.com/R8/
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bem94
Cool project! I see lots of toy RISC CPUs but rarely anything CISCy. This sort
of thing is great as a house-keeping core for bigger RTL designs, especially
as it is synthesis-able.

Are you planning to extend the ISA at all?

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jacquesm
I'm not sure if < 40 instructions should count as 'CISC' by any definition.
Besides the instructions that are implemented fall squarely in the 'RISC'
domain: low count, very few addressing modes, memory access separate from
operations.

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microtherion
"Move immediate value to memory address" seems like a prototypically CISCy
operation to me.

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ajb
Typical CISC is an instructions which uses both a load/store pipeline slot and
an ALU pipeline slot. 'move immediate to address' just uses a load/store slot
and fits into a normal risc microarchitecture; the reason you don't normally
get it is encoding constraints: the address typically uses the instruction
bits where the immediate would go.

Looking at the source, though, this processor uses a variable length
instruction; so it is at least a bit CISCy.

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gravypod
Are there any FPGAs that can fit into the PCI slot of Thinkpads (specifically
my X220). I want to play around with them but I don't want to lug around 30
development boards and cables.

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amenghra
Get an icestick (fpga on a USB stick). You can use an entire open source tool
chain (thanks to great reverse engineering work) although I would use the
default tools even if it implies running Windows in a VM.

Some other boards a pretty small. I have a Xilinx Spartan; really easy to
carry around.

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jfktrey
Second the default tools. The open source tools are really cool, but
especially if you're just starting out, the proprietary tools are much gentler
in helping you debug your own mistakes.

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vanjoe
I wouldn't say lattice tools are super helpful, I've spent more hours cursing
icecube2 than I care to recall.

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bedros
be careful with trademark from ARM, they already have R5 and R7 cpus, I'm not
sure about R8

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Cyph0n
There is the Audi R8 sports car, but I guess this is unrelated enough?

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godmodus
Can use same name for a _different_ product catigory. Same catogory ->
_somebody gonna geta hurt_

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ajb
Intel discovered to their cost that you can't trademark a number (hence
80486->pentium). Don't know if one letter is enough :-)

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jlebrech
how does verilog then translate onto a chip, does it try to fit it into the
space?

are there any tutorials for this?

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cryptarch
What's the license?

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ruchira66
it's free for personal and commercial use.

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cryptarch
Perhaps you could add a mention of the license on the project page and/or at
the top of the file?

If I'm understanding you right don't have a former license yet. You could use
something like MIT, Apache 2.0, CC0, GPL, LGPL or WTFPL, that would fit your
comment.

I think MIT or Apache 2.0 would be the safest choices (if you don't have a
preference for GNU/copyleft licenses).

I'm afraid a HN comment won't hold up in court as proof I have a license to
use a work.

~~~
ruchira66
Thanks for the licensing guide. I decided to use MIT license for the project.

Please let me know if you made anything useful with this processor!

