Need a simple hello world guide

Created by: silabs-robin

There is a problem that setting up the environment is complicated and we don't have a minimal example.

Currently the main README's "Getting Started" has a link to what OpenHW is and to the verif strategy document which is too technical for someone looking for a simple hello world. I see some /dev branches have added 40P and A6 links, and that might be sufficient (if 40x/s is similarly updated). But the readmes you find in mk/ and cv32e40x/sim/uvmt/ contain far too much information.

To make collaboration easier with either newcomers or 3rd parties, I think we should have a very minimal guide for running hello world. It is also not clear which of the environment variables are essential for this, and which are extraneous.

Example:

To run hello world for e.g. cv32e40x, cd into cv32e40x/sim/uvmt and run make test TEST=hello-world.

The environment needs to be set up correctly. The following is a minimal example (read more in todo link).

setenv CV_CORE cv32e40x
setenv CV_SW_TOOLCHAIN <point to gcc>
setenv CV_SIMULATOR <set to "xrun" or some other simulator>
setenv USE_ISS NO