7 ms·

Eh. The ISA of RISC-V is free and open. Actual implementations of RISC-V are not, in general. The point of RISC-V is that you may have the option to switch impl

Eh. The ISA of RISC-V is free and open. Actual implementations of RISC-V are not, in general. The point of RISC-V is that you may have the option to switch implementations if you become fed up with your current supplier, without having to switch ISA.

oytis 4y ago
As far as I understand in Qualcomm case it is exactly a third-party implementation of licensed ARM ISA. So looks like an ideal case for switching to RISC-V.
- madeofpalk 4y ago
  As far as I understand, Arm ISA is a lot stricter, whereas RISC-V implementations can have more variations. So it's 'easier' to switch to a different implementation of Arm as you'll be more sure that the processor works the same way. At least, that's the idea.
UltraViolence 4y ago
First of all: the licensing of RISC-V is much cheaper than ARM. I've seen Chinese RISC-V MCU's that only cost a dime or less. And these aren't itty-bitty 4-bit parts mind you, but comparable to ARM M0 or M4. Secondly, there are numerous open-source RISC-V designs out there to give any company a head start and the freedom to modify it as they see fit.
- delfinom 4y ago
  Those OSS RISCV designs are academic largely. True performance RISCV designs are going to be people's money maker and never open sourced. A head start is great but that still costs expensive skilled engineering time to actually make a worthwhile product. And due to licensing of OSS, it may be a bad thing for a company to build their multi-billion dollar business on something they need to open source for someone to immediately knock them off and kill their business. In the hardware world, we live and die by our design secrets. If someone can simply copy you exactly, they can completely undercut you and basically put you out of business. A bit different than the software world.
  - Hizonner 4y ago
    > And due to licensing of OSS, it may be a bad thing for a company to build their multi-billion dollar business on something they need to open source for someone to immediately knock them off and kill their business. Nobody, other than a company that makes only CPUs or CPU IP, adds value in the CPU. If you're anybody else, a CPU is a commodity dingus that you need to run your software, which is where the interesting things for your billion dollar business go on. If you are a large user of CPUs, or even CPU IP, there's only so much you're going to pay before you band together with other large users and cut out the person collecting the payments. The freedom to make small tweaks may also be a a nice extra for a very few users. Maybe you need a special functional unit to speed something up. But your core value is not going to be in those tweaks, and in fact you save money if you can upstream them and get somebody else to do some or all of the maintenance. That's what happened with the operating system layer. Nobody worries that they're "building their business" on the Linux kernel.
    - klelatti 4y ago
      > > Nobody, other than a company that makes only CPUs or CPU IP, adds value in the CPU. Errr Apple?
      - deleted 4y ago
        [deleted]
      - cestith 4y ago
        The CPU/GPU/Memory SoC in a Mac is a line item, albeit a hefty line. The one in an iPhone is more so. They sell systems as their product, not retail box processors. It's thought an M1 cost them around $50 in a $2000 laptop.
        klelatti 4y ago
        Agree with all of this but not sure how it relates to the point I was making.
- colonwqbang 4y ago
  What you are saying isn't wrong. But I'd like to point out is that the companies that buy "Chinese RISC-V MCUs" may not be the same ones who license Arm CPU IPs and put them next to logic from other suppliers on a custom built chip. For one thing, it is seen as risky nowadays to use Chinese IP in chips, ever since Mr. Trump said that the US government wouldn't buy certain Chinese tech. The bigger cost in chip development is verification, not design. If you use open-source IP, I assume you need to take on this burden yourself or pay someone else to do it. The cost for doing that may well be more than the cost to license an already verified core (Arm or RISC-V ISA).
SanjayMehta 4y ago
The easiest way to get started with RISC-V seems to be the Polarfire devices from Microchip.
brucehoult 4y ago
We are talking here about companies such as Qualcomm or NVIDIA that have the ability to design their own cores. RISC-V is indeed completely free to them.

oytis 4y ago

As far as I understand in Qualcomm case it is exactly a third-party implementation of licensed ARM ISA. So looks like an ideal case for switching to RISC-V.

madeofpalk 4y ago
As far as I understand, Arm ISA is a lot stricter, whereas RISC-V implementations can have more variations. So it's 'easier' to switch to a different implementation of Arm as you'll be more sure that the processor works the same way. At least, that's the idea.

UltraViolence 4y ago

First of all: the licensing of RISC-V is much cheaper than ARM. I've seen Chinese RISC-V MCU's that only cost a dime or less. And these aren't itty-bitty 4-bit parts mind you, but comparable to ARM M0 or M4. Secondly, there are numerous open-source RISC-V designs out there to give any company a head start and the freedom to modify it as they see fit.

delfinom 4y ago
Those OSS RISCV designs are academic largely. True performance RISCV designs are going to be people's money maker and never open sourced. A head start is great but that still costs expensive skilled engineering time to actually make a worthwhile product. And due to licensing of OSS, it may be a bad thing for a company to build their multi-billion dollar business on something they need to open source for someone to immediately knock them off and kill their business. In the hardware world, we live and die by our design secrets. If someone can simply copy you exactly, they can completely undercut you and basically put you out of business. A bit different than the software world.
- Hizonner 4y ago
  > And due to licensing of OSS, it may be a bad thing for a company to build their multi-billion dollar business on something they need to open source for someone to immediately knock them off and kill their business. Nobody, other than a company that makes only CPUs or CPU IP, adds value in the CPU. If you're anybody else, a CPU is a commodity dingus that you need to run your software, which is where the interesting things for your billion dollar business go on. If you are a large user of CPUs, or even CPU IP, there's only so much you're going to pay before you band together with other large users and cut out the person collecting the payments. The freedom to make small tweaks may also be a a nice extra for a very few users. Maybe you need a special functional unit to speed something up. But your core value is not going to be in those tweaks, and in fact you save money if you can upstream them and get somebody else to do some or all of the maintenance. That's what happened with the operating system layer. Nobody worries that they're "building their business" on the Linux kernel.
  - klelatti 4y ago
    > > Nobody, other than a company that makes only CPUs or CPU IP, adds value in the CPU. Errr Apple?
    - deleted 4y ago
      [deleted]
    - cestith 4y ago
      The CPU/GPU/Memory SoC in a Mac is a line item, albeit a hefty line. The one in an iPhone is more so. They sell systems as their product, not retail box processors. It's thought an M1 cost them around $50 in a $2000 laptop.
      - klelatti 4y ago
        Agree with all of this but not sure how it relates to the point I was making.
colonwqbang 4y ago
What you are saying isn't wrong. But I'd like to point out is that the companies that buy "Chinese RISC-V MCUs" may not be the same ones who license Arm CPU IPs and put them next to logic from other suppliers on a custom built chip. For one thing, it is seen as risky nowadays to use Chinese IP in chips, ever since Mr. Trump said that the US government wouldn't buy certain Chinese tech. The bigger cost in chip development is verification, not design. If you use open-source IP, I assume you need to take on this burden yourself or pay someone else to do it. The cost for doing that may well be more than the cost to license an already verified core (Arm or RISC-V ISA).

SanjayMehta 4y ago

The easiest way to get started with RISC-V seems to be the Polarfire devices from Microchip.

brucehoult 4y ago

We are talking here about companies such as Qualcomm or NVIDIA that have the ability to design their own cores. RISC-V is indeed completely free to them.