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> There is so much code actually shared, or with very little variations, that it is a big win for code re-use to stick to 64bits, even for "embedded". "Embedde

> There is so much code actually shared, or with very little variations, that it is a big win for code re-use to stick to 64bits, even for "embedded". "Embedded" is a broad concept. Sure there's applications where the size/cost penalty of a 64 bit core is insignificant. Or you want it anyway to use software designed for it (like common Linux distributions). But there's also a loooottt of applications where you really want the simplest, lowest cost, lowest power cores available: solar powered mesh sensor networks, RFID tags, tiny controllers in eg. an USB peripheral, AA powered childrens toys, that clock in your microwave, etc, etc, etc. Often referred to as "deeply embedded". For such uses, 32 bit cores like ARM Cortex-M series or RV32I (or even -E) rule. To the point that even ancient 8/16 bit architectures like 8051 are still used. It would be dumb to put a 64b core there just to 're-use code paths'. C compilers are a thing, and assembly programmers know how to handle different ISAs.

sylware 3y ago
This is exactly what I do not want to do: use a C compiler. And even though 32bits RISC-V assembly is very close to 64bits RISC-V assembly, I don't want to rely too much on an assembler macro pre-processor to do the switch. And yes "embedded" is nowdays quite "broad". Of course, for the "very" "embedded" even a 32bits RISC-V core is overkill, a broadly available 8bits processor will be enough if you really are going for the bucks, which I am not going for. In my world, I would have 2 targets, a mini domestic server (email, maybe a few small web servers, more?). A linux based OS would be the start, but I guess it would end up more like a custom patchwork of code paths from various projects than vanilla "linux". There are already many 64bits RISC-V SOC with existing boards for that. Then a mini-board with a SOC with at its center a 64bits RISC-V MCU for a DYO custom keyboard, which would require a USB device hardware block, flash memory, timer, a lot of GPIOs, etc. There are already some options here too, but a tad too overkill (often with "AI"). Ofc, if I could get a RISC-V powerful workstation on which I could play AAA 3D games...

sylware 3y ago

This is exactly what I do not want to do: use a C compiler. And even though 32bits RISC-V assembly is very close to 64bits RISC-V assembly, I don't want to rely too much on an assembler macro pre-processor to do the switch. And yes "embedded" is nowdays quite "broad". Of course, for the "very" "embedded" even a 32bits RISC-V core is overkill, a broadly available 8bits processor will be enough if you really are going for the bucks, which I am not going for. In my world, I would have 2 targets, a mini domestic server (email, maybe a few small web servers, more?). A linux based OS would be the start, but I guess it would end up more like a custom patchwork of code paths from various projects than vanilla "linux". There are already many 64bits RISC-V SOC with existing boards for that. Then a mini-board with a SOC with at its center a 64bits RISC-V MCU for a DYO custom keyboard, which would require a USB device hardware block, flash memory, timer, a lot of GPIOs, etc. There are already some options here too, but a tad too overkill (often with "AI"). Ofc, if I could get a RISC-V powerful workstation on which I could play AAA 3D games...