

Why mips and not RiscV? I would assume it’s easier to emulate in software and has good support in linux
EDIT: found it
Some architectures had arbitrarily-shifted operands all the time (ARM), some have shitty addressing modes necessitating that they would be slow (RISCV), some would need more than 4KB to even decode instructions (x86), and some were just too complex to emulate in so little space (PPC).
Could it be the pc relative addressing often used on risc-v would be slow to run on 4004?


I think you missed the point. Imagine 2 devices, device A has a chip with flash memory that contains a binary blob with firmware. Device B doesn’t have built-in flash storage so it requires the driver to load the same binary blob during boot. Both devices are reprogrammable and both contain the same closed source firmware. However device A would be allowed but device B would not. From my point of view they are the same device. The fact that you don’t know how to reprogram device A doesn’t make it more or less proprietary.