
Building a RISC-V PC - spystath
https://abopen.com/news/building-a-risc-v-pc/
======
avisaven
If you want to play with RISC-V hardware right now, I highly recommend taking
a look at the Sipeed MAIX [1]. It has a bunch of neat features along with a
dedicated RISC-V processor, for a considerably lower price (~$35 if my memory
is correct). I've received a M1w, which is working quite well. The campaign
has ended but it seems you can get the hardware on external retailers, however
I cannot vouch for these [2]. They also have a Telegram chat where the
developers of the product talk quite a bit, and if you ever have any questions
they're quite responsive and helpful.

[1] [https://www.indiegogo.com/projects/sipeed-maix-the-world-
fir...](https://www.indiegogo.com/projects/sipeed-maix-the-world-first-
risc-v-64-ai-module) [2] [https://www.seeedstudio.com/Sipeed-MAIX-I-module-
WiFi-versio...](https://www.seeedstudio.com/Sipeed-MAIX-I-module-WiFi-
version-1st-RISC-V-64-AI-Module-K210-insid-p-3206.html)

~~~
krasin
Additional info could be found at the SoC manufacturer website and their
Github ([1], [2]).

As an additional insight: this is an offspring of one of the developers of
mining hardware, Canaan. They have released the chip right before their
anticipated IPO: [https://coingeek.com/crypto-miner-maker-canaan-eyes-going-
pu...](https://coingeek.com/crypto-miner-maker-canaan-eyes-going-public-new-
york-report/)

1\. [https://kendryte.com/](https://kendryte.com/)

2\. [https://github.com/kendryte](https://github.com/kendryte)

~~~
listic
_hardcore FFT_ !

------
shadeslayer
I saw one of these at FOSDEM recently and it could already run a full Linux
graphics stack all the way to KDE Plasma. So cool :D

------
microcolonel
I want to get back to porting Chromium, because when AMD tries the second time
around [0] (edit: maybe _third_ time around, as wmf below points out) to do a
pin-compatible RISC (maybe this time it's one of the Zen 4 platforms or
whatever), I want to pop the phattest GPU in that thing and enjoy.

[0]: [https://www.extremetech.com/computing/181867-amds-project-
sk...](https://www.extremetech.com/computing/181867-amds-project-skybridge-
new-arm-and-x86-chips-that-are-pin-compatible)

~~~
dfox
Actually it would be fourth time around, as the K7 Athlons/Thunderbirds were
electrically compatible with Alpha 21264, although OK, it was not pin nor
mechanically compatible as Alpha CPUs need additional directly attached serial
(EE)PROM with boot PALcode/microcode/firmware/initial contents of L2 cache. On
the other hand on typical lowend Alpha systems this PROM contained complete
enought i386 emulator that it could run PC-style BIOS as part of hardware
initialization (ie. work with ISA/PCI cards with x86 code in PROMs), somewhat
ugly and scary is the fact that large part of the firmware variant needed for
booting Windows NT was actually i386 code running in said emulator. (And then
there is Linux, which in the somewhat Tour de force way does not care about
the underlying PALcode API _)

\--- _) Alpha is to a large extent the ultimate RISC architecture that on the
user side does not have any implicit sideefects of instructions and syscalls
and interrupts work by simply exchanging two register sets. The idea is that
there is PALcode which is the only privileged code running on the CPU, which
then keeps track of whether whatever is currently running in userspace is user
or kernel code and passes messages between these, to some extent it is
microkernel as part of the CPU, which you additionally can as an OS modify (in
reality you could not, because the PALcode is amalgamation of both the OS
semantics, quirks of the actual CPU implementation and the actual motherboard
in given system)

~~~
FullyFunctional
RISC-V is very VERY close to Alpha in this respect. There are no flags,
everything is communicated via registers (which makes semantics clean and
dynamic scheduling cheaper), and the equivalent of PALcode exist (called
platform specific SBI calls, executing in M-mode).

IMhO, RISC-V is slightly better than Alpha on a many fronts: the conditional
branches which compares two registers would take two instructions on Alpha (on
the critical path), RISC-V code density is better with compressed, the
encoding is slightly cheaper for hardware, it ISA is more forward-
looking/extensible, oh and it's open of course. The only thing I miss are the
POPC/CTZ/CLZ instructions, but the B set will include them for implementations
that have it.

UPDATE: more RISC-V upsides

~~~
cestith
Also, RISC-V hasn't been bought, litigated, and buried. Alpha is great, but
we're about as likely to get new implementations of it at this point as we are
of the 6809 or v20.

RISC-V's future is looking better and better. Who knows? Maybe TSMC or Samsung
or one of the smaller fabs puts out a multicore version on a fairly modern
process node and gets a multi-player motherboard market built in Taipei,
Seoul, and Shenzen. It could be a player in laptops, desktops, tablets, and
mobile rather than just embedded and SBCs. It could even be done without a
premium going to Intel, AMD, ARM, nVidia, TI, Freescale, or IBM. The
possibilities are exciting, because every time I hear about this ISA and its
implementations it's better news.

------
x15
A great interview on the first Linux port on RISC:
[https://www.youtube.com/watch?v=EZMA3Ge144U](https://www.youtube.com/watch?v=EZMA3Ge144U)

------
VoxPelli
One of the amazing possibilities with RISC-V will be how it democratizes chip
designing and by that opens up the ability to innovate in an area of computing
that so far has been reserved to a selected few.

RISC-V isn't really about price or performance – it's about innovation,
agility, exploration and new frontiers.

------
snazz
I had heard of the SiFive/HiFive Unleashed, but not of the expansion board.
I’m surprised that it “just worked” and I really like the case!

~~~
bcaa7f3a8bbc
The article didn't mention that the development board costs 1000 USD and the
expansion board costs another 2000 USD, and it's only a barebone system, a
full system comparable to a high-performance PC would require another 500 USD.
At this price level (~3000+USD), one can almost purchase an OpenPOWER-based
workstation (as we already have seen, the crowdfund campaign for Talos Secure
Workstation failed due to its price,
[https://www.phoronix.com/scan.php?page=article&item=talos-
wo...](https://www.phoronix.com/scan.php?page=article&item=talos-
workstation&num=1)). So no, I still don't think RISC-V is as usable as a PC
for an average user at its current shape as a prototype for developers.

~~~
Palomides
you can get a nice, complete POWER9 desktop tower for $2,364.99

[https://secure.raptorcs.com/content/TLSDS3/intro.html](https://secure.raptorcs.com/content/TLSDS3/intro.html)

Probably more open, too.

~~~
nickpsecurity
You can download a lot of the RISC-V's source to use in FPGA's or your own
hardware. Nobody has given me a link to the same for POWER9. There's also a
lower risk of getting patent sued for selling RISC-V versus IBM's I.P.. I'd
say POWER9 is nowhere near as open as the RISC-V offering. It's "open" like
OpenVMS: using the word to get dollars more than maximizing openness.

~~~
Palomides
I meant open regarding the hardware, bootloader, etc., but it seems like
sifive has released more code since I last looked and you can now bring up a
board without any blobs.

And yeah, we won't be seeing openpower on FPGAs anytime soon.

------
tachyonbeam
How does the quad-core 64-bit RISC-V processor used perform? Genuinely curious
to know how to compares to a modern ARM cellphone chip, for example.

~~~
rwmj
I have two of these boards which are part of the Fedora build system (see
[http://fedora.riscv.rocks/koji/](http://fedora.riscv.rocks/koji/)). The
performance is fine for light development, but they're not blazingly fast --
and we don't expect that, it's the first development board available only in
small quantities. The chip itself is an in-order design, something like the
A53.

~~~
mwcampbell
If you can take one of those boards off of build duty for long enough (maybe
half an hour?), it would be interesting to see the results of a UnixBench [1]
run.

[1]: [https://github.com/kdlucas/byte-
unixbench](https://github.com/kdlucas/byte-unixbench)

~~~
zamadatix
[https://openbenchmarking.org/s/SiFive](https://openbenchmarking.org/s/SiFive)

------
mrweasel
Is there some reason for the "funny" form factor of the HiFive boards? It
seems like a mini-ITX or ATX form factor would be more appealing to many.

~~~
justinclift
Probably because it's a development board in spirit, not really intended for
any kind of PC usage.

Hopefully some future product(s) with more PC compatible form factors come out
in the next few years. :)

------
justinclift
Using some right angle PCIe connectors for the graphics and USB expansion
cards, they'd probably be able to shrink the height of that case
significantly.

------
gmueckl
Now if the HiFive could be scaled uo to match the performance of a current x86
CPU, this might become a serious contender for a decent set of applications.

~~~
yjftsjthsd-h
It doesn't need to hit the same perf as high-end x86 to be useful for a lot of
uses; observe the sheer number of IoT projects run on Raspberry Pi and the
like. Now, of course, I think we all would like to see high-end riscv be a
thing so we can ditch x86 in that market segment too.

~~~
rbanffy
It needs to have a better performance per dollar, however, or its not a great
option.

~~~
brucehoult
It's an early-access prototype for engineers to use to develop software for
the cheap products that will come in the next year or two. It's not intended
for hobbyists.

~~~
rbanffy
I'm not referring to this specific hardware - I know this is not consumer-
ready - but to RISC-V overall. If we want to sell a RISC-V-based x86/ARM
replacement, it can't cost more than the well-known, multi-sourced part for
the same application.

As an engineer, I care about the elegance of the underlying hardware/ISA, but
when it's time to buy tech for a client, I can't afford to do that.

------
Timothycquinn
Anybody have an idea what the BOM cost is of this build?

~~~
baobrien
The Risc-V board was about $1000 the last time I checked, and the microsemi
expansion thing was $2000. The SiFive board is for a small run development
chip and the microsemi has a big honkin' FPGA, so the prices aren't
unreasonable for that.

------
agumonkey
microsemi logo looks sooo much like a 90s MSDN/Office one I took 10 seconds to
be sure if it was MICROSOFT or not

------
dfed-mpls
"RISC architecture is gonna change everything."

~~~
TomVDB
Out in the real world, I know of cases where proprietary CPU or DSP IP was
rejected in favor of RISC-V alternatives.

RISC-V may not change everything, but I do believe that it will change on
thing in a major way: the financials of CPU IP such as Tensilica, Cortex-M0,
ARC etc.

There is very little friction in replacing embedded controllers that are not
customer facing. And that's a market were $0.01 in licensing fees can be a big
deal.

Edit: in the maker world, the so-called Blue Pill is incredibly popular. It
has an STM32F103 SOC with a 72MHz Cortex M3 and tons of digital and analog
interfaces. On AliExpress, these boards go for $1.60 a piece!

[https://wiki.stm32duino.com/index.php?title=Blue_Pill](https://wiki.stm32duino.com/index.php?title=Blue_Pill)

~~~
MisterTea
> There is very little friction in replacing embedded controllers that are not
> customer facing. And that's a market were $0.01 in licensing fees can be a
> big deal.

Reminds me of USB vs Firewire. Firewire was the superior of the two yet it
lost. Why? USB didn't have Fw's $0.25 licensing fee per manufactured device.

~~~
TomVDB
$0.25 is very, very high.

I don't know who was supposed to pay the $0.25, but gizmos like external hard
drives is a commodity market with razor thin gross margins.

Whoever decided that $0.25 was reasonable for that kind of market (Apple?)
essentially killed the protocol right there.

Edit: here's the story: [https://arstechnica.com/gadgets/2017/06/the-rise-and-
fall-of...](https://arstechnica.com/gadgets/2017/06/the-rise-and-fall-of-
firewire-the-standard-everyone-couldnt-quite-agree-on/)

Steve Jobs changed royalty model from a flat licensing fee to a $1 fee per
port (insane!), Intel walked away and cancelled all FireWire development, Jobs
lowered it then to $0.25 but Intel didn't come back.

~~~
Laforet
I remember PC and laptops equipped with a single fireware port well into the
late 2000s even though peripherals are pretty much extinct by that time. Even
Apple themselves appeared to have given up by removing them from newer ipods.

------
rnvhhynr
Why a video instead of text + photos?

~~~
chrisseaton
I don't know what you mean - the article looks to me like text and photos, and
then a short video as well.

------
silur
I'm a big fan of RISC-V but HiFive completely ruined the whole point. I was
excited for a _proper_ open ISA because it would open up super low cost
hardware development. But looking at the $35 raspberry pi with a license-bound
ARM ISA and a supposedly open source board for $1000 it looks like HiFive is
playing by intel's or ARM's rules. No chance for risc-v adoption with this
ridiculous overpricing

~~~
pjc50
> super low cost hardware development.

There are lots of things that cost money in hardware design, and ISA licensing
is a very small part of them.

Edit: I wonder if I should do a rather confrontational blog post telling
people why Open hardware is never going to be the free lunch that open source
software is..

~~~
wolfgke
> There are lots of things that cost money in hardware design, and ISA
> licensing is a very small part of them.

Indeed - and this is exactly the point of ISA licensing (and IP blocks): to
make it sufficiently cheaper to just license the ISA or IP blocks instead of
developing the product from ground up.

~~~
q3k
Right, but with RISC-V you can actually have some competition to implement
RISC-V between multiple vendors, hopefully driving prices down.

~~~
wolfgke
> Right, but with RISC-V you can actually have some competition to implement
> RISC-V between multiple vendors, hopefully driving prices down.

I am not convinced that competition is always a good thing here: lots of
competitors lead to shrinking margins. This means less money that can be
invested into innovating by the respective companies.

