(while being an order of magnitude simpler)

The main pitfall while writing assembly is the abuse of a preprocessor. Being dependent on the grotesquely and absurdely complex and massive compilers out there is one thing, but moving that dependency to a complex preprocessor is not that much better. So caution and care about that issue must be kept in mind.

I wish all RISC-V CPU vendors to pay the silicium real estate price for 64bits because writting once a 64bits RISC-V code and to be able to "run-ish" it everywhere, from "embeded" to servers passing thru workstation, wow.

I am writting currently x86_64 assembly, namely the manual "register-ization" of some code paths is done, ready for an easy RISC-V port. Not to mention RISC-V has double the amount of registers, and some code paths will really benefits from this additional register space (intel plans to follow that route).

Ofc, this will be mostly micro-arch agnostic assembly code, as it is the case already for x86_64, with maybe simple or very generic static "optimizations" (cache line, alignment, registerization, leveraging some instruction fusions, etc). Worst case scenario, adapted (not rewritten from scratch) assembly written code paths to fit better on a micro-arch with a runtime switch/installation... if really needed. I guess correct code will become very important, maybe more than fast code ("should" become true for hardware design too, if the performance penalty is not too high).

RISC-V will need compiler support though, that for legacy support, and sometimes, humanization of the assembly output of some compiled programs may be usefull.

All that depends on the success or not of RISC-V, which for that will need ultra-performant implementations all over the board, micro-archs and best silicium process.

RISC-V is not perfect, but a more than good enough modern ISA, and the real risk of fragmentation is 32bits/64bits code paths even though some care was provided to make 32bits<->64bits code adapation easy.

Mistakes will be made (micro-arch with critical bugs), so it won't happen overnight.

the preprocessor thing depends on what it is that bothers you about the grotesque compilers. a macro preprocessor can be pretty small; gpm (basically unix m6) was reputedly 250 machine instructions

historically 'worse is better' and 'the innovator's dilemma' suggest that adoption of an innovation like risc-v depends more on conquering the low end of the market long before the high end. but then there's the tesla roadster...

shame about the t bit tho