⚠️ Major code edits / cleanups

[stnolting]

• remove co-processor timeout logic from ALU (use the watchdog timer to ensure the CPU does not get stuck instead)
• rename CPU data bus unit: neorv32_cpu_bus.vhd -> neorv32_cpu_lsu.vhd ("load/store unit")
• move entire PMP logic (including CSRs) into a new design file neorv32_cpu_pmp.vhd
• move FPU CSRs from central control unit to FPU module
• constrain maximum number of HPMs to 13 ([m]hpmcounter3[h] to [m]hpmcounter15[h])
• minor RTL edits and cleanups

ℹ️ Moving the entire PMP/FPU CSR logic into optional (if ... generate) design units ensures that all of the logic is trimmed when the according module is not enabled.

[NikLeberg]

Hi @stnolting since you are already changing and updating stuff.. some small error just detected: in neorv32_cpu_amo.c the doxygen comments for @param[in] wdata of all amomin* functions is wrong. It says MAX-ed instead of MIN-ed. Seems like a copy-paste mistake. 😉

I could open a pr but I think that is overkill. How would you like such rather small errors to be fixed? Shall I collect them in a special draft pr where I could collect multiple smaller correction commits? Or am I allowed to directly push such small fixes to main? 🤔

[stnolting]

@NikLeberg

some small error just detected: in neorv32_cpu_amo.c the doxygen comments for @param[in] wdata of all amomin* functions is wrong. It says MAX-ed instead of MIN-ed. Seems like a copy-paste mistake. 😉

Thanks for finding!

How would you like such rather small errors to be fixed? Shall I collect them in a special draft pr where I could collect multiple smaller correction commits?

Sounds good to me.

Or am I allowed to directly push such small fixes to main?

I think you cannot push to main directly (even as a collaborator). 🤔 I need to check the branch protection rules again...