Mistaken use of variable assignment in ibex_cs_registers.sv

[chris-stafford-64]

File ibex_cs_registers.sv contains following:
logic cheri_exception_code = mcause_q == 6'h1C;

However, cheri_exception_code is a variable (not a net) and is therefore initialised 'X' at time 0ns and remains 'X'.

Probably really wanted continuous assignment:
logic cheri_exception_code;
assign cheri_exception_code = mcause_q == 6'h1C;

[marnovandermaas]

I wonder why this worked before in that case. Either way I've taken your suggestion and fixed it here: lowRISC/cheriot-ibex@97de74d
This'll be pulled in the next time we pull in the latest version of CHERIoT Ibex.

[chris-stafford-64]

Thanks Marno.
Yes strange that it has previously worked. Problem was highlighted using Xcelium simulator.