Comment by ploxiln

This blog post is very defensive and argumentative, which I guess is fair considering Dmitry's post is similarly inflammatory, but most of it was really not convincing:

> Simply put, the things a high-end CPU needs are diametrically opposed to the things a small cost-saving microcontroller core needs.

> The conclusion he draws is that no single ISA can serve both ends, and that RISC-V fans are fooling themselves, in theory the premise is true. The conclusion does not follow, and I can show you why from three parts sitting on my desk as we speak.

> CH32V003. This is the cheap "RV32EC" with sixteen registers, no multiplier, no divider, machine mode only,

> CH32H417. A dual core MCU that is unmatched in performance to price point and is at the higher end of the MCU line

> Baochip. A VexRISC-V with an MMU built around a stack thats open from silicon to os Baochip-1x: A Mostly-Open, 22nm SoC for High Assurance Applications

Uh, which one of these is a datacenter server cpu? Or a workstation cpu? Or at least a developer laptop cpu? How about a Raspberry Pi 4 level SBC (supporting latest ubuntu and fedora releases, driving a display that runs a browser and plays video ...)

There's a lot of angry indignation but it seems obvious that Dmitry is quite right about this.

But I found this is where this blog post starts making a lot of sense:

> Has anyone tried adding an MMU to a Cortex-M? The physical tradeoffs are real, the difference is that with RISC-V, the ISA owner does not decide for you where that boundary must be drawn. If you want virtual memory on ARM you license a Cortex-A instead, which is a different core family, a different profile, a different negotiation, and a different royalty.

> Compare what happened with Baochip. The RISC-V privileged specification defines supervisor mode and Sv32 paging as optional things an implementation may provide. VexRISC-V is an open core, somebody added an MMU to it. bunnie built a chip around it and runs a microkernel with real process isolation on it

Yeah, that is a good point. We're still in the low-end specialty realm, but that is real interesting advantage for RISC-V, a good reason for it to exist.

As for shipping to Trinidad and Tobago ... this post is trying too hard to turn this into moral issue, but it seems a bit random (OrangePi cost $30 and shipped free? you can also get arm-based and stuff from the same places), and the vast majority of people don't live on semi-remote islands, it doesn't make sense to consider this kind of accessibility above all else, and it's strange to blame Dmitry for not thinking of you here.