hashbreaker2021

How do you figure? FreeBSD, Linux, LLVM, GCC, golang, (O)KL4 and most recently OpenBSD run on RISC-V. Generally speaking, code branches in FreeBSD and OpenBSD are *years ahead* of consumer computing offered by Apple which still borrows heavily from those upstream libre/open source software operating systems (e.g. LibreSSL, OpenSSH).

In 2020, Micro Magic demonstrated a 5GHz RISC-V CPU consuming just 1W of power. Do you know of *any* ARM CPU at that clockspeed sipping power so frugally? I do not. ONiO.zero also announced a 24MHz RISC-V CPU some time ago which uses energy harvesting techniques so that it has no active power draw. Sure, there are some ARM CPU implementations which are similar to that, but the licensing fees, particularly as ARM IP is caught up in a SoftBank/NVidia murky mess with litigation being involved doesn't exactly make it seem as if it is primed for the future. As it is, ARM is really a 1980s vintage CPU ISA, with some 64bit grafts, not entirely dissimilar to AMD64 extensions for the 1970s x86 Intel CPU ISA.

Since 2010, RISC-V has already been taught in undergraduate programs in schools of merit, meaning that the future workforce will be ready to jump on RISC-V in the commercial sector. MIT's Xv6 (https://pdos.csail.mit.edu/6.828/2012/xv6.html) is essentially a "Lion's Commentary on Unix" without the apocrypha due to the AT&T vs BSDi lawsuit which caused so many headaches in the 1990s.

Maybe you're thinking: "but RISC-V doesn't even implement an FPU!" without acknowledging the reality that most FPU designs are 1980s vintage IEEE 754 which in academia are losing favor as contrasted with posit/unum alternatives.

Sure, RISC-V isn't ubiquitous, yet, but I think that is just a matter of time. The HiFive Unmatched which began shipping earlier this year uses U740 64-bit RISC-V CPUs in a 28nm process from TSMC. However, TSMC and SiFive have already demonstrated a 5nm iteration of their next gen RISC-V CPU as a proof of concept, and we already know that TSMC is spinning up a 2nm fab, so I think it follows that RISC-V will be ready for that whenever the wafers are primed for lithography.

Others already mentioned NVidia's roadmap from migrating from 32bit ARM cores in their GPUs to 64bit RISC-V designs. Moreover, the RISC-V spec already has provisions for 128bit addressing. Even from an assembly perspective, the ISA is refreshingly, intentionally, simply designed without decades of vendor proprietary cruft tacked on as afterthoughts to attempt to differentiate/feature parity themselves with "competitors" (e.g. MMX, Neon, SSE, etc.), it has vector math as a default, not as an after thought. When reading Andrew Waterman and David A Patterson's The RISC-V Reader: An Open Architecture Atlas, I was in awe at how much information was presented in so few pages. I think not since K&R have I read a technical text which seemed so condensed and so useful.

You can run a full blown BSD or Linux distro on RISC-V systems *today*, I think that is already immediately useful. The BeagleBoard.org® Foundation has begun shipping preliminary samples of the BeagleV to developers who are looking for a RISC-V Raspberry Pi sort of alternative and its estimated street price is going to be $149 to $199 depending upon equipped RAM. At least in my experience with a BeagleBone Black in years past, their efforts were significantly better than any Raspberry Pi I ever used. That's just the low end too. For people who are using FPGAs for higher end research, Olof Kindgren's SERV RISC-V implementation has already demonstrated being able to spin up > 5000 cores on some higher end FPGA development boards. For organizations which tape out silicon (or at least design it even if they may be fabless, such as AMD, NVidia and Apple), RISC-V seems extremely promising on a number of levels.

I've applied to jobs at Apple in the past without much luck, even when I had internal recommendations the furthest I ever got was a phone screening, but I will probably toss my résumé at this requisition. Honestly, while I did end up buying an M1 Apple Silicon Mac last year, I was pretty disheartened and hoped that they would have already been iterating their own RISC-V designs rather than simply present yet another renamed variant of an ARM CPU. I was also programming on MC68K NeXT machines before most people had ever heard of objective-C and at least circa 1994, the best performing systems running NeXT Step were some 486dx2 systems running at 66MHz at my college, though they still seemed pokey and inefficient as contrasted with MIPS based Silicon Graphics workstations, and certainly Commodore (RIP) made substantially more efficient and versatile use of MC68K hardware than Apple ever figured out.

I don't see this as being a bad move by Apple by any stretch of the imagination. Intel has already been rumored to be working on their own RISC-V designs, and supposedly made an offer to buy SiFive earlier this year, despite having been an early investor in the company, that seems to have not come to fruition. Apple, and others can continue to iterate ARM, but it is pretty clear that it's kind of like hot rodding an old jalopy at this point. RISC-V is where the puck is heading, rather than where it has been, to mangle a quote Steve Jobs borrowed from Wayne Gretzky.

I mean, I guess you could use a RISC-V as a microcontroller, insomuch as the SiFive HiFive1 (rev B, though ostensibly the discontinued initial release as well) is more or less a drop in replacement for an Arduino, but as someone who was doing PIC level coding in the 1980s, there are more efficient and smaller package alternatives to Arduinos too, PIC logic never went away, it just got denser and more powerful with increased ASIC integration and these days there are even video games such as Shenzhen I/O which are more advanced logic tools than SPICE systems from a few decades ago (it honestly wouldn't surprise me if the developer of Shenzhen I/O is using a video game as a way to crowd source cheaper IC designs for strange consumer products that the players will never realize they had a hand in directly). Realistically though, RISC-V hardware can run real operating systems *today*. macOS and Windows haven't joined the party yet, and I think we can already guess Microsoft will be last to finish as usual.

melgross said:

 Right now, RISC-V is years behind even the simplest ARM general purpose CPU. It’s being used for specialized tasks. It’s designed to be a controller for other sub units, such as a neural engine, or a machine learning processor, or optical analytics.

It will take years to be useful, if it ever is, for a low end phone, or similar device. A major reason it’s so efficient is that it only has 50 instructions.

I can see Apple being interested because it would be irresponsible to look the other way. Notice that the engineer they’re looking for Also needs experience with ARM. I suspect that Apple is looking to see if some aspects of this can be used inside their ARM based instruction set chips, but not to replace them