Run a simple bare metal program?

[nachiket]

Is this a better repo to use for simple experiments than the original?

I see there's a pointer to running the ELF simulation at this URL: https://spinalhdl.github.io/VexiiRiscv-RTD/master/VexiiRiscv/HowToUse/index.html

How/where do I supply my own code to generate an ELF for functional and performance evaluation?

[Dolu1990]

Is this a better repo to use for simple experiments than the original?

original meaning VexRiscv ? It is probably a bit early if you think about FPGA / SoC, but for raw CPU simulation, i think it is good.

I would say here :
ext/NaxSoftware/baremetal
you can add a new "project" there, then cd your project and "make rv32ima" for instance

note that by default, most option / optimization for the CPU architecture are disabled.