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VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

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Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#41

Post by comex »

monocasa wrote: post #30
londons_explore wrote: post #27

Earlier quoted context omitted.

Name some... Any task where perf per dollar matters also boils down to perf per watt, since watts cost dollars...

Say, robotics where the difference between an FPGA and something else is way overshadowed by the motors. Or really basically anywhere that has you interacting with the real world directly connected to your compute, and not just compute off in a datacenter.

> Or really basically anywhere that has you interacting with the real world directly connected to your compute, and not just compute off in a datacenter.

Which, at least in mass-market applications, mostly happens on phones and other battery-powered devices. :)

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#42

Post by monocasa »

comex wrote: post #41
monocasa wrote: post #30

Earlier quoted context omitted.

Say, robotics where the difference between an FPGA and something else is way overshadowed by the motors. Or really basically anywhere that has you interacting with the real world directly connected to your compute, and not just compute off in a datacenter.

> Or really basically anywhere that has you interacting with the real world directly connected to your compute, and not just compute off in a datacenter. Which, at least in mass-market applications, mostly happens on phones and other battery-powered devices. :)

Or the dozens of other devices in your house that have the benefit of mains voltage.

I don't think perf per watt was a differentiator in the compute chosen for your TV, your monitor, your AV receiver, your fridge, etc.

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#43

Post by alfalfasprout »

londons_explore wrote: post #27
monocasa wrote: post #17

Earlier quoted context omitted.

There's a lot of use cases today where perf per watt doesn't matter.

Name some... Any task where perf per dollar matters also boils down to perf per watt, since watts cost dollars...

realtime systems. avionics, robots, radar processing, low latency network appliances, trading platforms...

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#44

Post by alfalfasprout »

comex wrote: post #41
monocasa wrote: post #30

Earlier quoted context omitted.

Say, robotics where the difference between an FPGA and something else is way overshadowed by the motors. Or really basically anywhere that has you interacting with the real world directly connected to your compute, and not just compute off in a datacenter.

> Or really basically anywhere that has you interacting with the real world directly connected to your compute, and not just compute off in a datacenter. Which, at least in mass-market applications, mostly happens on phones and other battery-powered devices. :)

But many, many important applications are not mass-market.

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#45

Post by roosterdawn »

gchadwick wrote: post #7

Worth mentioning SymbiFlow: https://symbiflow.github.io/ , it's a fully open-source flow for FPGAs, Xilinx support (targetting the Arty A7 that the project in this story uses for instance) is on the way so hopefully won't be long until you can build a opensource RISC-V SoC that can run Linux entirely on open source tooling.

You read my mind. This is awesome. Wonder how hard it'd be to DIY a smartphone and go from there.

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#46

Post by rjsw »

rkagerer wrote: post #12

I'm disappointed today's general purpose CPU's and microcontrollers don't come with some integrated FPGA space, similar to how you have SRAM and other peripherals. Intel talked about it a few years back [1] but I'm not sure anything materialized. The closest I've seen in popular chips is a few gates worth of programmable logic. Are there any hidden gems I've missed out on? [1] https://www.nextplatform.com/2018/05/24/…

There was a company that had an FPGA implementation of HyperTransport so that you could link the FPGA to a network of AMD Opteron CPUs.

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#47

Post by jimktrains2 »

zozbot234 wrote: post #32
rkagerer wrote: post #12

I'm disappointed today's general purpose CPU's and microcontrollers don't come with some integrated FPGA space, similar to how you have SRAM and other peripherals. Intel talked about it a few years back [1] but I'm not sure anything materialized. The closest I've seen in popular chips is a few gates worth of programmable logic. Are there any hidden gems I've missed out on? [1] https://www.nextplatform.com/2018/05/24/…

Don't general purpose CPU's and μC's use replaceable microcode as part of the chip implementation? Shouldn't that boil down to the same thing?

The microcode is still controlling a microprocessor, not defining gates. It's more like microcode is the assembly language and the x86 or w/e is byte code.

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#48

Post by litghost »

gchadwick wrote: post #7

Worth mentioning SymbiFlow: https://symbiflow.github.io/ , it's a fully open-source flow for FPGAs, Xilinx support (targetting the Arty A7 that the project in this story uses for instance) is on the way so hopefully won't be long until you can build a opensource RISC-V SoC that can run Linux entirely on open source tooling.

To be clear, creating a linux capable Artix-7 image using only open source tools can be done today, right now! https://github.com/SymbiFlow/symbiflow-examples

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#49

Post by 5- »

eebynight wrote: post #16

The fact that it fits in the 35T version with room to spare is pretty huge, especially since certain packages of the 35T start as low as $35 for a single chip, no MOQ. I could see myself dropping one of these on a homemade project if I ever spend the time making a reliable reflow oven...

it runs on the 5k lut ice40up5k, e.g. as the default bootloader in fomu: https://www.crowdsupply.com/sutajio-kosagi/fomu

(the whole thing fits inside the usb-a port)

Re: VexRiscv is a quadcore, Linux-capable RISC-V softcore for FPGA

#50

Post by Teknoman117 »

rkagerer wrote: post #12

I'm disappointed today's general purpose CPU's and microcontrollers don't come with some integrated FPGA space, similar to how you have SRAM and other peripherals. Intel talked about it a few years back [1] but I'm not sure anything materialized. The closest I've seen in popular chips is a few gates worth of programmable logic. Are there any hidden gems I've missed out on? [1] https://www.nextplatform.com/2018/05/24/…

The FPSLIC comes to mind (https://www.digikey.com/catalog/en/partgroup/fpslic/14188?mp...) and the Cypress PSoC
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