Do 8051/8031 assembly like its 1984

Or like it's 2025. Plenty of current-production parts using an 8051 core as either their main sequencer, or as a low power core with bigger options on the main power rail.

8051 rapidly being replaced by RISC-V now.

Can you give an example? I see RISC-V being used to replace custom 16 and 32 bit cores, and M0-class ARM cores, in the 10k+ gate range, but haven't really seen a migration in the 8 bit space.

I have personally ported a usb c usbpd stack from 8051 to cortex m0 to rv32ec. I can’t talk for gate count, it for code size the biggest factor was the compiler, with ARMCC giving the smallest code. As the rom was larger than the core, that was a bigger factor in gate count.

It can be hidden away in SoC IP blocks, like DisplayPort blocks, too.

8051 is cool, but no one is going to be writing their own homebrew assembler for them, there are plenty of FOSS ones.

And even assembly itself is going away, sdcc is a perfectly good compiler which is sufficient for a lot of 8051 applications.

rv32ec is indeed less dense than thumb2.

This is of course not the case anymore with the newer bitmanip and code size extensions, but it holds true for the older, crude rv32ec.

Why not? I wrote a 6502 assembler a few months ago - despite being born decades too late It's fun