Open-source chip RISC-V to take on closed x86, ARM CPUs

http://www.computerworld.com.au/article/618724/open-source-chip-mimics-linux-path-take-closed-x86-arm-cpus/

by jumpkickhit • 9 years ago

354 151 9 years ago

computerworld.com.au

DonbunEf7• 9 years ago

I want to buy RISC-V, both to play with and to support the cause. What are my options like and should I buy something now or wait for the next generation?

pmorici• 9 years ago

The HiFive1 from sifive for $60 is what I got.

https://www.sifive.com/products/hifive1/

wanderingjew• 9 years ago

You can buy one from SiFive: https://www.crowdsupply.com/sifive/hifive1 although it's going to be a while until a RISC-V chip will be packaged on a board with USB, Ethernet, SATA, and all peripherals that make an ATX motherboard or a Raspberry Pi worth owning.

deepnotderp4• 9 years ago

SiFive

microcolonel5• 9 years ago

You can buy the HiFive1 board (I have a few and they're swell), but it's more of a microcontroller than an application processor, the board is Arduino compatible. If you want something more like a Raspberry Pi or bigger, you'll have to wait a bit longer.

The Freedom Unleashed platform is coming down the pipe, and you can pre-evaluate it on an FPGA board (albeit at lower frequency, and fairly pricy since it's a complex design and requires a fairly large FPGA to prototype). I won't pretend to know when they'll have a standard Freedom U500 SoC dev board, but it will have multiple cores, PCIe 3.0, USB 3, Gigabit ethernet, and DDR4 compatibility according to their website[1].

[1] https://www.sifive.com/products/freedom/

ktta• 9 years ago

Apart from buying an actual dev kit like HiFive from SiFive, a great way to get into it is to buy SiFive's FPGA kits

https://dev.sifive.com/freedom-soc/evaluate/fpga/

The FPGA board can be used for other things too. If you are really adventurous, I'd suggest buying a FPGA board with better chip so you can fit in larger IP blocks in the future. It will work perfectly fine as a replacement for the above FPGA kit I've linked to.

My suggestion would be this[1]. It has a pretty large LUT count so you can go nuts. The RAM and Ethernet will be pretty useful if you want to run linux[2] and test out stuff. It'll be a bit hard to run linux on it right now.

On the other hand, you can choose a Parallela board[3] which comes with a FPGA chip along with a new (soon to be retired) arch called epiphany. Here[4] is a GSoC project which runs linux on that board using the FPGA.

[1] http://store.digilentinc.com/nexys-4-ddr-artix-7-fpga-traine... [2]: https://github.com/riscv/riscv-linux [3]: https://www.parallella.org/ [4]: https://github.com/eliaskousk/parallella-riscv

e12e2• 9 years ago

I see that what they recommend for the freedom platform

https://www.sifive.com/products/freedom/

today, is a dev board

https://dev.sifive.com/freedom-soc/evaluate/fpga/

that costs around 3500 USD:

https://www.avnet.com/shop/us/p/kits-and-tools/development-k...

Do anyone here know what kind of "classic pc" performance one is likely to get out of a board like that? Could you get on the order of low-end pc (~500 dollar soc / netbook with real gigabit ethernet, sata6 and usb3) from something like that, if paired up with a reasonable cpu design?

ddcc7• 9 years ago

For an FPGA to play around with, the Lattice ECP-5G is really nice: http://www.latticesemi.com/en/Products/FPGAandCPLD/ECP5andEC... . PCIE and DDR3, in a $99 dev board.

FullyFunctional5• 9 years ago

(Public service announcement: https://riscv.org/forum/)

Others have the SiFive chip, but if you want to boot Linux then your best option currently is running Rocket on an FPGA kit. I expect that we'll soon have more options. If you just want to play around, then I'd recommend Spike or Fabrice's https://bellard.org/riscvemu/

tyingq2• 9 years ago

People mentioned the siFive option, but that's a microcontroller. If you were looking for a 64 bit processor implementation, without having to use an FPGA...

It looks like the first dev board that would be capable of running linux will likely be the lowRISC project.

"We are expecting to crowdfund an initial instantiation of the lowRISC platform during the course of 2017" http://www.lowrisc.org/

brucehoult2• 9 years ago

I'll buy a LoweRISC as soon as they have something for sale (and I have one of the first HiFive1s). But at the rate both organisations are progressing I expect to be able to get a quad core 1.6 GHz 64 bit RISC-V "Pi-like" board from SiFive before LowRISC. Possibly even this year. I've gathered from other things they've said that they're sampling wafers with that SoC about now.

Ideally, they'll both succeed.

alkoumpa2• 9 years ago

I wonder how of those fit in a zedboard. (not going to ask how many hours of tool fighting that would require though).

sidereal• 9 years ago

Running on a Zedboard is quite well documented; only took me a couple of hours to do it from scratch following their instructions: https://github.com/ucb-bar/fpga-zynq

alkoumpa2• 9 years ago

I meant in a SIMT fashion, more like a GPU

blitmap2• 9 years ago

I look forward to a RISC-V proc powering my laptop with some ridiculous Nvidia GPU. We must escape x86 :(

deepnotderp4• 9 years ago

Atm, arm is likely a better fit for that.

swiley2• 9 years ago

Right now the arm SBCs actually make functional desktops. There's very little you can't do on a raspberry pi other than run closed software.

djsumdog• 9 years ago

I wish ARM made all their manufactures use UEFI. Microsoft did for their phones, but the bootloaders are locked. All the other ARM devices are SoCs with random shit connected to random pins and non-upstreamable kernels. It's not a platform.

For a new design to work, it really need to be a sold platform, with a spec and kernels that don't need per-device images to boot and run. Device trees help, but they're just not enough.

monk_e_boy• 9 years ago

Twice the battery life and all the computing power :) sounds like heaven

zanny2• 9 years ago

There is some gentle irony in wanting an open source ISA CPU paired with a GPU so proprietary the ISA is not even public knowledge.

Nomentatus4• 9 years ago

"The journey of a thousand miles..."

blitmap2• 9 years ago

I'm looking forward to the day we can operate dedicated, proprietary GPUs like black boxes we can turn on and off at will as optional accelerators. :-)

filereaper• 9 years ago

Many people claim to want an open-source chip, but end up balking at its price tag, this is exactly why Raptor Engineering's Talos failed. [1]

I've pretty much given up hope on a non-x86 based chip hitting our desktops, the closest to reach will be ARM.

The economies of scale aren't there, I pretty much end up rolling my eyes at each of these articles.

[1] https://www.raptorengineering.com/TALOS/prerelease.php

nickik• 9 years ago

The hole point of a free ISA is that many different people can produce them so that it will reach a economy of scale and chip producers will face competition making dirving down price.

Its not garantied to work but its a worty target.

jeffdavis3• 9 years ago

Free is about freedom, not price.

microtherion• 9 years ago

With more producers, you get more competition, but LESS economy of scale, and for a product like this (with demand being limited initially), this was already a critical concern.

abeyer• 9 years ago

You have a point, but I think there is a reasonable midpoint that Talos missed altogether. RISC-V's move towards RPi/Arduino style mini-systems lets them get a market going at a price point that has some chance to get some uptake early, and hopefully grow from there.

Talos seemed amazing, and I was always fond of the ppc/power architecture and wished for something more modern than an old G5 mac, but $7k for a desktop is just more than even most early adopters are willing to do.

orionblastar• 9 years ago

That was the Apple Lisa's folly. It cost too much than most early adopters wanted to pay.

The PPC was a good brand but Intel out innovated them making faster x86 chips cheaper than PPC makers could. Apple had to move to Intel to compete with Intel PCs running Windows or Linux. Amiga still uses PPC but they are expensive.

Arm chips are so cheap to make that there is the $5 Raspberry PI Zero cheapest computer on a chip tech.

Risc-V would have to be priced like the Arm chips are, or else there would be no benefit to use them unless you like paying more for an open source chip that is free as in freedom and more expensive.

yellowapple• 9 years ago

Talos failed because Raptor tried to sell a high-end server in desktop clothing when the market called for maybe a PowerBook at most. They needed to start smaller with something lower-power.

webaholic• 9 years ago

RISC-V is atleast 10 years away from competing with x86 and ARM. It is just now getting to a point where it can power arduino class hardware. Long way to go... but looks promising.

legulere• 9 years ago

Where do you get this from? It will still take a bit until the privileged spec is finalized, but what is holding RISC-V back then?

orbifold• 9 years ago

Implementations that are competitive with current x86 and ARM at the highend

jbarham4• 9 years ago

The Freedom E310 chip in the HiFive1 board is shipping today and is already competitive with embedded ARM: https://www.crowdsupply.com/sifive/hifive1/#comparisons. It's comically faster (i.e., 100x) than the AVR chip in the Arduino Uno board, but the similar form factor makes it cheap & easy for early adopters to play around with.

I'd bet that within five years a good proportion, even the majority, of Amazon & Google servers, will be running on RISC V chips.

dom05• 9 years ago

It's comically faster (i.e., 100x) than the AVR chip in the Arduino Uno board

Beating AVR cores on performance is like stealing candy from a baby. No one hands out prizes for that.

sweden11• 9 years ago

That sheet doesn't mean anything, they are comparing a microcontroller clocked at a frequency of 300 MHz with microcontrollers clocked at 30 MHz.

Of course that they have better performance... Misleading marketing material.

nezza-_-2• 9 years ago

Is there a power consumption comparison?

nl2• 9 years ago

I'd bet that within five years a good proportion, even the majority, of Amazon & Google servers, will be running on RISC V chips.

Can I take the other side of that bet?

I'm mildly bullish on RISC V, but displacing x86/AMD64 in the data center in 2 generations (servers generally have a 2 year refresh cycle) seems fairly optimistic.

ARM hasn't managed it, despite some good attempts. Nor has AMD, nor Power8/9.

kbumsik• 9 years ago

It is not competitive at all yet. In the world of embedded system, the processing power is not all about embedded system. The CPU takes less than 10% of the sillicon of the chip. Look at what what it got - A single SPI, some PWMs, even so I2C, no hardware timer, no ADC/DAC. So it should rely on software implementation of peripheral. Lack of hardware peripherals will lead to fail real time requirements. It may slower than even arduino in some operations. Moreover, where are you going to use 320MHz with tiny 16kb of RAM? This chip might be useful for calculating such as DSP or Machine learning unit but this is yet practically useless for a microcontroller. There is yet a long way to take off.

Sanddancer• 9 years ago

The big problem with the E310 is that after you've prototyped something and want to design a custom board, you've got a much more difficult task ahead of you. The AVR needs a significantly fewer number of support chips, as it has onboard flash, has pretty large voltage tolerances, has adcs, etc. It gets even murkier when you start considering boards from other companies like STMicro, which have Cortex-M7s, are competitive in performance and have boards that go for half the cost of a hifive1. It's interesting if you want to poke around with Risc-V for the purpose of poking around, but i wouldn't want to start a serious project based on it at the current time.

wyldfire• 9 years ago

I thought that microprocessor production and design was fraught with risk of infringing on other designers' patents (even for original ISAs). I can see that industry heavyweights have arrived to support RISC-V, so hopefully that comes with a team of professors/lawyers that could defend them. But, why now? Why couldn't this have happened sooner? Didn't Sun try to create an open SPARC processor design? What does RISC-V have that it didn't?

Is the intent for RISC-V to compete with modern high-end CPU designs, or do we just want to have royalty-free microprocessors for our embedded devices?

You might be surprised (at least I was) to learn that peripherals like hard drives and PCI-add-in cards usually have their own CPU executing their own software. Those processors are often MIPS/ARM/etc based and the manufacturer has to shell out to someone to be able to use that, even if they designed the processor themselves. I can see how this particular market is ripe for something like RISC-V. But does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq?

I sound incredulous because this seems surprising to me, but I have no evidence to suggest whether it's as unlikely as I think. I've certainly seen open source software designs far superior to closed source ones, so maybe hardware design is no different?

microcolonel5• 9 years ago

There are a number of things that make RISC-V different from OpenSPARC. One is that OpenSPARC is not a very scalable design, it could probably only ever work in servers and workstations, and workstations are essentially a monoculture. Another reason is timing: manufacturing processes have effectively stopped yielding performance and power gains as the fundamental constraint (distance between components on chip) doesn't get any smaller. This means that in order to keep the pace up for any popular workload, many new microarchitectures will need to be created. RISC-V is amenable to a wide array of microarchitectural decisions, and doesn't carry the architectural baggage of ARM and MIPS licensing and technical quirks, or the impossible licensing of x86.

But does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq?

Except for Intel, none of these manufacturers have any reason to resist RISC-V. All of these vendors can directly port knowledge from one ISA to another. So really it becomes a matter of "will there be a demand for RISC-V hardware in the server and workstation markets?", and the answer to that is a firm "maybe".

I think that today, since most software is written in high level languages which are at least as abstract as C, there is little reason why a new ISA couldn't take hold in any of these markets if hardware vendors can promise good things to ISVs and to customers who write their own software.

At present, there is a considerable barrier to entry for new designers and manufacturers to approach ARM, POWER, and MIPS, and basically no hope of manufacturing an AMD64. ARM is not the cuddly RISC architecture people think it is, it is in many ways nearly as quirky as x86, and therefore very expensive to enter and innovate on. Furthermore, it can take more than a year to negotiate an architectural license with ARM, your company or the market might no longer exist by the time you close the deal. POWER is not too far off on licensing, and it's not all that elegant either (though far more surmountable than ARM). MIPS lacks industry momentum and standardized high performance feature sets (wide vector compute, hardware security features), and its custodian company seems to barely acknowledge it exists.

All in all, nobody knows if it'll work out, but there are good reasons for RISC-V to succeed in the market. The challenges also seem surmountable.

dom05• 9 years ago

OpenSPARC is GPL. And OpenSPARC means the T1/T2 designs (high throughput, very low single-threaded performance) which are useless outside their niche.

CalChris3• 9 years ago

RISC-V is amenable to a wide array of microarchitectural decisions

As is ARMv8. Applied Micro, Broadcom, Cavium, Huawei, Nvidia, AMD, Samsung and Apple are all architectural licensees with radically different microarchitectural implementations. For example, Nvidia is Transmeta code-morphing style implementation. Also, Intel and AMD continue to innovate in the x86 space.

At this date, RISC-V has no fundamental advantage over any of these architectures and then has the fundamental disadvantage of not having access to their IP. You're lining up against Usain Bolt and your advantage is that you're wearing organic cotton. That's just not gonna work.

indolering3• 9 years ago

The RISC-V team was very careful in establishing prior art for every design decision. The patents on ISAs tend to be on their quirks, so keeping things truly minimal helps avoid all of that complexity.

Like a lot of what Sun did, prior open chip designs weren't good enough. Academics starting with a clean slate and a 20+ years of additional experience gives RISC-V real advantages over MIPS and ARM.

The primary advantage is that RISC-V is truly RISC: they have a core ISA that is frozen but extendable. This means that they can have application-specific CPUs with intelligent fallback and full compatibility.

As to why now, well, they came up with RISC-V as a teaching ISA and started getting emails from industry asking why it had changed from last semester. It turns out that chip manufacturing has gotten cheap, with custom runs on 28nm processes going for $30K.

You are correct in that their early target market are co-processors and other niche components. Just getting a license from ARM is 10+ million dollars. But the biggest cost in building your own ISA is investment in software and tooling. RISC-V gives a common foundation for everyone to build on.

However, their intent is indeed to bring competition at every level. Their licensing scheme was chosen specifically to allow big players to create IP and keep the secret sauce to themselves, unlike SPARC V8 and OpenRISC.

Apple creates their own CPU and GPU designs, Google has custom hardware for machine learning, and Samsung is about to overtake Intel as the world's largest chip manufacturer. Why should they keep shelling out billions to ARM, Intel, and AMD just to use their ISA?

dom05• 9 years ago

Just getting a license from ARM is 10+ million dollars.

Which license? ARM offers several different models.

Apple creates their own CPU and GPU designs, Google has custom hardware for machine learning, and Samsung is about to overtake Intel as the world's largest chip manufacturer. Why should they keep shelling out billions to ARM, Intel, and AMD just to use their ISA?

The Google hardware we know (TPU) for learning does not use ARM at all, so they would obviously pay nothing there. BigCo's like Apple or Samsung are probably ARM partners, so no per-design/unit fees.

Samsung Electronics may become the biggest chip manufacturer soon, but much like with smartphones that's only by turnover, not profit. But profit is what ultimately finances your R&D.

An interesting titbit is that even Intel and ARM are, at least on paper, partners.

_ph_• 9 years ago

For the costs, they do not only get the license to use the ISA, but the whole processor design, as in the "source code" to the whole processor. As a licensee, you place that design together with any other electronics you create (or license separately) on a chip to create the device you want.

mtgx3• 9 years ago

does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq?

Yes, and no. RISC-V is disruptive [1] to both ARM and x86. But before it can run (compete with Intel CPUs), it needs to crawl (compete with low-end ARM CPUs/microcontrollers). It could take a decade or more before RISC-V competes at the high-end. Basically think of it as following ARM's path but on a much more accelerated path (for many different reasons: much larger chip market these days, being open source and royalty-free, etc).

[1] https://www.youtube.com/watch?v=mbPiAzzGap0

noir_lord• 9 years ago

I think part of the accelerated path will be that we are reaching the limits of 'easy' (in the billions already) process improvements.

When everyone and his dog has 14nm you can't rely on process to keep you ahead, Ryzen has shown this partially recently, Broadwell level IPC on an Octacore processor for less than Intel sells a Quad core.

It's going to be a bloodbath as the middle eats into the top.

figers• 9 years ago

Isn't ARM the RISC solution that is already here? Already dominating mobile, Microsoft is soon to be announcing x86 apps running on Windows on ARM

wyager2• 9 years ago

ARM is too license-encumbered. If we're going to switch away from x86, it might as well be to something that admits free development and production.

sweden11• 9 years ago

Things are not that straight forward, I wrote a better comment here: https://news.ycombinator.com/item?id=14284409

jbarham4• 9 years ago

Relevant article: http://makezine.com/2017/05/03/sifive-brings-open-source-to-...

pubby• 9 years ago

As someone not knowledgeable about hardware, I really enjoyed reading Agner Fog's message board where he and others discuss creating a new open source instruction set: http://agner.org/optimize/blog/read.php?i=421

RISC-V is discussed some, and part of the discussion is how to improve it.

sweden11• 9 years ago

I see on this thread a lot of people getting blind-folded by the "open-source" term attached to the headline of this article.

First of all RISC-V can mean more than one thing: it can refer to the architecture, which is in fact open and free to use, or it can refer to the implementation of the same architecture, which will not be necessarily free or open source. For example, check the so claimed SiFive company which was promising free and open source implementations of RISC-V: http://www.eetimes.com/document.asp?doc_id=1331690

"“A year ago there was quite a debate if people would license a core if there was a free version, [but now] we’ve seen significant demand for customers who don’t want an open-source version but one better documented with a company behind it,” said Jack Kang, vice president of product and business development at SiFive."

By the end of the day, they just decided to follow ARM's path by providing license fees to their CPUs.

Secondly, when people say that RISC-V is "free" and "open-source" and that will allow companies to create cheaper and more open hardware, that is just an illusion. There are many more things on a SoC other than a CPU (like memories, communication buses, GPUs, power management processors, and so on). Cutting costs on a CPU will not make the cost of an SoC go down to zero, the CPU is just a small part of the puzzle. With RISC-V, you either need to implement the CPU yourself (which will be extremely expensive and time consuming) or you will have to find someone who provides with CPU cores already implemented. And of course that you need to have support and guarantees that the cores you bought will work on silicon. There will be always a huge cost associated when shipping CPUs, you can't escape from that.

You can already imagine that open-source hardware doesn't play by the same rules as open-source software, it's a completely different game with completely different rules.

And people speak of ARM's royalties like if they were a very bad thing. Truth to be told, the royalties you pay ARM can be a very good deal taking into account that you get access to silicon proven CPU cores, support from the best engineers in the industry and you automatically get covered by the many CPU patents that ARM owns. And you can even choose on how you want to pay for ARM's CPU licenses: you can either choose to license an already implemented CPU design by ARM or you can buy an architectural license and implement your CPU completely from scratch (this is what Apple and Qualcomm are current doing). You don't need to be completely tied to ARM. Even in the royalty fees you can choose whether you want to pay a big upfront license fee but then paying low royalties per device or you can choose to pay a low upfront license but compensating on the royalties per device.

There is a lot of misinformation going around the possibilities of RISC-V, mostly of this misinformation coming from people involved in the development of the spec. Don't be fooled by the buzzwords "open-source hardware" and "free hardware".

jbarham4• 9 years ago

You don't need to be completely tied to ARM.

The point is that if you want to use the ARM ISA you have to pay ARM. Not so with RISC-V. Anyone is free to fab a RISC-V chip without paying royalties.

sweden11• 9 years ago

You are talking like you could download RISC-V from the internet and send it to the foundry for mass production without additional costs or effort.

RISC-V is just a document, is not an implementation. There are many costs involved into designing a CPU that end up costing much more money than paying a license fee.

Check this comment: https://news.ycombinator.com/item?id=14284450

zanny2• 9 years ago

A lot of the interest behind open ISAs like RISC-V isn't from a cost perspective, because most people recognize that the cost differences are negligible.

They want to avoid the Intel scenario, where a company controls an ISA that industries depend on, and can force their ideology on implementing silicon for whatever ends they want.

ARM, being proprietary and controlled by the company can do the same. If you want a specific part built, you need the permission of ARM to do anything involving the ISA.

If you are going to build all civilization on the top of an ISA, it can't be reasonable to subjugate that ecosystem to the whims of one board of directors.

Nokinside3• 9 years ago

I believe this is incorrect. It seems that there is lots of confusion related to RISC-V.

Only RISC-V ISA and some simple (and relatively inefficient) architectural designs are free and without royalties.

But when someone develops efficient RISC-V microarchitecture they are not going to provide it free. If some company develops RISC-V based architecture that is competitive with AMD,Intel or ARM, they are going to ask good money for it.

psydk• 9 years ago

After enjoying coding on 680x0 in my youth and later being frustrated by x86, I acclaim that new ISA. There is a design decision I'm curious about but I could not find related information. How did they come with the names "x0, x1, x2..." for general purpose registers, instead of the more conventional "r0, r1, r2..."?

_chris_• 9 years ago

x for "fixed point". r for "register" is too vague.

roryisok• 9 years ago

I always thought ARM chips were RISC. shows what I know

indolering3• 9 years ago

That's how they started out, but there is always pressure to add new instructions for niche markets. But since there isn't any coherent way to implement extensions it means they have to pollute the entire ISA. RISC-V was carefully designed to allow for extensions.

FullyFunctional5• 9 years ago

No it was never a [real] RISC. Even the very first version included predication and shift in most instructions. They weren't even fast. The event that changed everything was when DEC Alpha engineers (for reasons I don't know) decided to use their expertise to created StrongARM. This ironically ended up at Intel and was renamed XScale, before being spun out. (EDIT: grammar & typos)

faragon• 9 years ago

AFAIK, most advanced RISC-V design includes superscalar and OoOE (e.g. comparable to a MIPS R10000 (1995) or an Intel Pentium Pro (1995)), while the RISC-V for the IoT is comparable to a typical single instructions per clock RISC CPU, e.g. MIPS R3000 (1988).

The success in the IoT will depend not only in a cheaper price because of no royalties, but also in the "ecosystem": peripherals, buses, etc. Running Linux is a huge start, so I have no doubt it can be a success in this field.

Regarding the use in mobile and desktop, it will have to wait until SIMD extensions are introduced, and software being adapted (e.g. ffmpeg/libav including RISC-V assembly SIMD implementation for the codecs).

Anyway, realistically, for the RISC-V getting enough traction, some big player should bet on that, which is currently highly improbable, unless some Apple/Samsung/Huawei/Google gets crazy enough for doing it.

homero• 9 years ago

Nvidia would be perfect

pjmlp2• 9 years ago

NVidia is busy with their own ARM designs.

Nokinside3• 9 years ago

Regarding the use in mobile and desktop, it will have to wait until SIMD extensions are introduced

I'm little confused about this talk and comments in here relating to open source in high performance applications (desktop, servers etc).

The RISC-V ISA is open source, I get that. There can also be open source Verilog/VHDL designs available. They are probably good for small low performance IoT applications and old processes.

But there is long way from ISA to silicon in high performance VLSI processor design for a new processes and foundries. Architecture, logic synthesis, timing analysis, floor planning, routing and placement, and ungodly amount of testing .. I don't see anyone spending hundreds of millions of chip design for RISC-V ISA and open sourcing it.

In other words, if you want competitive RISC-V chip, some company must spend hundreds of millions to develop their own RISK-V chip architecture and they will not open source it.

peatmoss• 9 years ago

In other words, if you want competitive RISC-V chip, some company must spend hundreds of millions to develop their own RISK-V chip architecture...

I wonder if a country like Russia, wanting something that they can deploy without worrying that the NSA & Intel are cooperating on state spying, will eventually try and take something like this and bootstrap a domestic semiconductor line of business.

posterboy• 9 years ago

What is so special about reduced ISAs, what's the differentiating factors between them?

I mean they are so reduced that the ones I've seen are largely the same few logic ops. RAM access and interrupts might differ some, but a) memory access should follow the implementation and b) essentially everything else is memory mapped (avr, c51, pic)

FullyFunctional5• 9 years ago

To fully appreciate this, one would need much experience with microprocessor implementation. It's not reduced for the point of being simpler or smaller, but because it represent a local optimum of perf/area for running C code, especially for small to medium implementations.

However, much like the Alpha, RISC-V has been carefully designed to be efficient to scale UP, that is, to superscalar out-of-order implementations.

Do read the spec and the footnotes; they are delightful: https://raw.githubusercontent.com/riscv/riscv-isa-manual/mas...

jlebrech• 9 years ago

would there be a advantage to not only creating a reduced instruction set but a minimal instruction set and letting the compiler do the rest. especially when you can add a lot more cores, so that mul becomes a cpu core with a counter and add for example.

FullyFunctional5• 9 years ago

No.

restalis• 9 years ago

So many RISC options and almost none for CISC. If you want yet another low power chip, then it makes sense. If, however, you want to get real on efficient cache usage and a high instruction-per-execution ratio, just do yourself a favor and stop ignoring the costly experimenting results that the industry already paid for.

Nomentatus4• 9 years ago

This just doesn't match the research I've read. CISC wasn't about speed of execution, and x86 isn't an asset, there. (As I understand it Intel's expertise in compilers, emulation of CISC by RISC, and manufacturing are wonderful compensating factors.)

silur• 9 years ago

An opensource, non-licensed, low-cost embedded processor -> sifive sells it for 600.000$ minimum.

Open-source chip RISC-V to take on closed x86, ARM CPUs

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