microwatt

My favorite part of this project is the pretty large battery of test cases. A lot of chip rtl releases don't bother with open sourcing the verification too, and that's arguably more useful than the rtl in the first place. https://github.com/antonblanchard/microwatt/tree/master/test...

The FPU has an instruction for fast inverse square root. https://github.com/antonblanchard/microwatt/blob/master/fpu.... I presume v.state := ... is what the FPU will do next, like a deferred goto. you can unroll the whole process following that. lookup table: https://github.com/antonblanchard/microwatt/blob/master/fpu....

A softcore is a CPU to run on an FPGA. Microwatt fits in a Lattice ECP5 FPGA with 85,000 LUTs (plus some block ram). Not sure how you'd get to transistors from that, wild guess times by 15 maybe? (But then the FPGA also has other special hardware blocks intended for interfacing with DDR RAM and other things, so those would be more as well). You can see how the Power instruction decode is implemented https://github.com/antonblanchard/microwatt/blob/master/deco...

Yes, there are open core IPs for POWER: - https://github.com/OpenPOWERFoundation/a2i - https://github.com/OpenPOWERFoundation/a2o - https://github.com/antonblanchard/microwatt

Microwatt is the only one I know of. Built as a tiny fgpa core. https://github.com/antonblanchard/microwatt

I have several OpenPOWER systems, including the POWER9 I use as my usual desktop. Besides IBM and other server manufacturers like Tyan and Wistron, you can get them as Raptor workstations and servers. If you want an OpenPOWER design to play with, look at Microwatt ( https://github.com/antonblanchard/microwatt ) which is complete enough to boot Linux.

https://github.com/antonblanchard/microwatt is an example of a Linux-capable 64-bit core that has been submitted on multiple Open MPW shuttles: https://platform.efabless.com/projects/29 https://platform.efabless.com/projects/795 https://platform.efabless.com/projects/840

The ISA is open and royalty free. There are at least three open cores, all IBM funded or designed: https://github.com/antonblanchard/microwatt https://github.com/openpower-cores/a2o https://github.com/openpower-cores/a2i The last two are older but they work. Microwatt is developing by leaps and bounds.

At the other end of the scale, if anyone wants to play you can run a little openpower CPU on an FPGA with completely open source. https://github.com/antonblanchard/microwatt It's capable of running Linux, some example docs are https://shenki.github.io/boot-linux-on-microwatt/ The toolchain consists of "apt install gcc-powerpc64le-linux-gnu" on Debian, no funny downloads. And if you want to target a Lattice ECP5 board even the FPGA tools are also all open, thanks to Yosys and friends. All the openpower ISA spec PDFs are available for perusing on the openpower site.

What is the intended usage for that? As in used in Consumer PC ? Would microWatts [1] fit that purpose? Not only do you have an Open ISA as in OpenPower, you also have an Open implementation of that ISA. AFAIK RISC-V doesn't have anything similar, only open source design in embedded usage. Otherwise a low cost POWER10 ( or now Power10 without the capital... and I hate it ) wont make much sense. You are talking about ~30mm2+ per core design. It is huge. [1] https://github.com/antonblanchard/microwatt

Down thread folks were asking to run BeOS binaries on it, sounds like a great opportunity for a couple fun hacks. * ppc -> risc-v binary translator, much more tractable with fixed width 32 bit instructions * running this on an FPGA that already includes a RISC-V core like PolarFire and then instantiate a softcore PPC. hack Haiku to run the PPC processes on that core. Extra bonus points to dynamically instantiate PPC cores to meet load, make fast ones, wide ones, slow ones. What a time to be alive! https://github.com/antonblanchard/microwatt

An OpenPOWER one, likely this with modification: https://github.com/antonblanchard/microwatt

You could even build your own Power ISA system with Microwatt, which is fully synthesizeable and growing by leaps and bounds. https://github.com/antonblanchard/microwatt (Disclaimer: minor contributor) I really liked PA-RISC. I thought it was a clean ISA with good performance at the time and avoided many of the pitfalls of other implementations. I think HP didn't want to pour lots of money into it to keep it competitive, though, and was happy to bail out for Itanium when it was viable. My big C8000 is a power hungry titan, makes the Quad G5 seem thrifty.

You might be interested in what Anton Blanchard has been up to with the power ISA soft cores, it seems like his work has spanned the bulk of the FPGA toolkits, and I think his latest is taped out for the SKY130 run. His work is also being adapted for an openBMC replacement, which would offer an opportunity to dust off some old Xzibit templates, so thats good. https://github.com/antonblanchard/microwatt https://github.com/antonblanchard/chiselwatt https://www.efabless.com/projects/29 https://gitlab.raptorengineering.com/kestrel-collaboration/k...