1. 17
  1. 5

    There’s a bit of a winding road from new architecture to something you hold in your hands, as the author notes at the end in talking about affordable dev boards. What would you do with such a board? Probably not much you couldn’t do quicker, easier and cheaper with an ARM or other mainstream board, for now. So for most people it won’t be worth much until and unless there are useful and affordable commodity systems.

    But if you are a hardware builder, there is a good reason to care: most architectures aren’t free. Right now I’m looking at designing a new ASIC, and it’ll need a CPU. I’m prototyping in an FPGA. If I wanted to use an ARM core, I’d have to go and pay ARM a bunch of money, even if I were to write my own CPU core - because it uses their ISA. But if I use one of the free ISAs, like SPARC or RISC-V, then I can get going right now: there are free cores which I can use all the way from simulation to silicon. So for now I’m working with RISC-V.

    ARM have realised this hazard is real; they’ve made a couple of cores free for use with Xilinx FPGAs and I’m guessing that’s in part to lower the bar for the prototyping crowd like me. Licensing an ARM core isn’t that expensive (in the scheme of chip development), so we’ll see what everyone’s holding in 5-10 years’ time.

    1. 2

      I’m not deep into this but my impression is that RISC-V is interesting not because it’s different but because it’s being developed in the open, and is free to use, and is “modern” in that contains some of the best ideas in CPU design accumulated over the past few decades. Most (all?) of the “free” cores that can be used these days started out proprietary and were only made free to use because the companies that built them could no longer make money on them because they were made obsolete in the marketplace by something else and as a result, there is no demand for them. The fact that RISC-V is gaining popularity is proof enough that it offers something new or useful over existing ISAs.

      But I get that there’s also the argument to be made that these days the vast majority of users (even developers) should never bother to care about what CPU is inside their box, as long as it has the software they need. Those who care about whether their box has RISC-V or ARM or AMD64 inside are either hardware or system designers, or hobbyists who enjoy geeking out about such things.