
RISC-V port submitted for inclusion in GCC - BuuQu9hu
https://gcc.gnu.org/ml/gcc-patches/2017-01/msg00776.html
======
xja
RISC-V really seems to be gaining momentum with 2 crowdfunded silicon
implementations currently seeking funding:

[https://www.crowdsupply.com/onchip/open-v](https://www.crowdsupply.com/onchip/open-v)

[https://www.crowdsupply.com/sifive/hifive1](https://www.crowdsupply.com/sifive/hifive1)

Looking forward to a future where CPUs that are open hardware, from the
transistor up are generally available.

~~~
d33
Wait, so this is mostly a microcontroller chip, right? I keep hearing about
its applications in smartphones, but I kind of doubt it could make it @
160mhz... not to mention PCs.

Am I getting something wrong?

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gchadwick
Part of the problem is to produce a high-end RISC-V chip doesn't just need the
RISC-V core. It needs all of the supporting IP as well which can be
substantial (interconnect, system caches, memory controllers, peripherals
etc). Plus to produce something that can complete with modern mobile APs
you'll need to fab on a modern process (e.g. 28 or 20nm, though that's a bit
long in the tooth if you're targetting things coming out rather than matching
current technology, 16FF would be better) which increases costs substantially.
Simple, slow, microcontrollers can be fabbed on older and far cheaper
processes.

~~~
bogomipz
">16FF would be better"

Did you mean 16NM or are you referring to something else other than process
size?

~~~
gchadwick
rrmm is correct. 16FF is generally used to mean the 16nm FinFet process.

~~~
bogomipz
Ah OK I am glad I asked thanks then, thanks for link too.

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bostand
I find the "open the ISA and they will come" attitude very odd.

The ISA is the least of your problems. In fact the cpu itself is not really an
issue at this point. If you look up what linus and others have been
complaining about it has almost never been about the cpu itself (which are all
pretty open designs these days).

What we need right now is open boot, open firmware and most of all, an open
gpu that can compete with the state of the art.

~~~
Gracana
What CPU would you use with your open GPU? intel with their management engine
is out, you can't get an arm MPU without a gazillion other peripherals
onboard, nor a MIPS MPU, but maybe you could license the core.. except now you
have those licensing fees and issues. OpenSPARC might be a good candidate, but
it's an awfully big device to bootstrap the idea with. RISC-V is nice because
the community can start with the simpler device profiles and work their way
up.

~~~
bostand
The point I am trying to make is that you are trying to solve the wrong
problem, just because it happens to be a fun problem.

To address your last statement from another angle: this is not the first FOSS
cpu, it only happen to be hipp right now. Significant work has gone into the
other alternatives which now risk to be forgotten just because they are not SV
darlings.

~~~
BuuQu9hu
The other FOSS CPUs are irrelevant, precisely because they aren't "darlings"
and thus have no momentum.

~~~
bostand
Is momentum same thing as media exposure? Isn't that very dangerous?

Wouldn't it make open source much less democratic since the guy with friends
in media will always win instead of the guy with the best ideas?

~~~
jononor
Strawman, that claim has not been made. Which FOSS CPUs (out)competes the ones
that are based on RISC-V? Or work-in-progress that you think will in the
future?

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ramshorns

      > +   Copyright (C) 2011-2017 Free Software Foundation, Inc.
      > +   Contributed by Andrew Waterman (andrew@sifive.com).
    

It looks like there's been a resolution to the issue of copyright assignment
that was preventing RISC-V support in GCC.

[https://www.phoronix.com/scan.php?page=news_item&px=GCC-
RISC...](https://www.phoronix.com/scan.php?page=news_item&px=GCC-RISCV-Lawyer-
Hold)

~~~
bluecmd
FWIW, that is what stopped OpenRISC to become part of mainstream GCC.

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oretoz
RISC-V is a general puspose CPU architecture. Does something exist which is
open like RISC-V but for DSPs? I am asking because unless we have that, no
smartphone can be truly open and infact you can argue that it is what runs in
baseband that needs to be open rather than on the main CPU.

Ofcourse RISC-V is an architecture so not just applicable for smartphones but
the point remains. RISC-V solves half the problem but what about the other
half i.e. DSPs?

~~~
phkahler
>> RISC-V solves half the problem but what about the other half i.e. DSPs?

One thing at a time. I'd argue that graphics is still a huge hole in the open
hardware world. There are lots of things to be done.

~~~
oretoz
Is there something on the horizon for graphics and GPU?

~~~
phkahler
>> Is there something on the horizon for graphics and GPU?

There is the MIAOW open source GPU but it is based on an AMD instruction set,
so it's probably not viable for general use.

I believe in the short term the solution will be simply running LLVM-Pipe on a
bunch of RISC-V cores for software rendering. The SoCs will just have frame
buffer graphics. Another option is to have PCIe support (which HiFive is going
to) so you could at least recompile an open source driver for a proprietary
video card. I suspect that once RISC-V SoCs are running a full linux
distribution with one of these inferior graphics solutions then people will
jump in to make better open graphics hardware.

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rurban
Beautiful and surprisingly small port! No gyrations at all.

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Esau
I worry that when the time comes - RISC-V will not see high acceptence because
it is too expensive for the performance it provides. I hope that I am wrong
because I would love to own a truly open computer.

~~~
ktta
I'm actually a bit more confident. The only thing stopping manufacturers in
china from selling good CPUs (anything above tiny microcontrollers) is because
their investment won't pay off in case they get sued.

But with this open hardware, they can sell without any worries, anywhere
(apart from the problem with following standards). I actually think that this
might bring more investment and interest from them. Of course the high end
CPUs won't have so much diversification due to the complexity and it's
impossible for normal people to stay on par with the complex manufacturing
process of <22nm, but baby steps I guess.

~~~
ant6n
I'd be more worried about hardware backdoors.

~~~
ktta
Well, I'm worried about hardware backdoors even now too.

Although there is always the 'know your hardware' tag advertised with RISC-V,
that's not going to change until we have complete control(or trust) of the
fabs.

It's a bit like people being worried about malware/adware/spyware on their
phones/personal computers. Are you sure that right now, you have __no
__spyware? How can you be sure if you 're not compiled the code your self? If
you did compile the code and read all the lines of the code you compiled --
great achievement!.

So now, if your phone has been connected to the internet, how do you know
there wasn't a vuln that wasn't exploited, and a root kit installed with the
last app you thought was great and had to have it? Or even just the last JS
block wasn't malicious?

Sorry for the rant. I just wanted to convey complete security is an illusion
we know and make ourselves believe is the real thing. I'm a lot more
interested in the cost economics with RISC-V, and I don't really have to worry
security right now in the MCU, embedded space, where it is manageable (atleast
right now).

