Zero-width HWPE_SEL_BITS when NB_HWPES=1 ($clog2(1)==0)

[DanielKellerM]

Summary:
When NB_HWPES is set to 1, $clog2(NB_HWPES) evaluates to 0 for HWPE_SEL_BITS. Any vector declared as [HWPE_SEL_BITS-1:0] becomes [-1:0] and will give compilation errors.

Affected code:

cluster_peripherals/cluster_control_unit/cluster_control_unit.sv

Line 71 in e464eb9

localparam HWPE_SEL_BITS = $clog2(NB_HWPES)

Possible fix:
localparam HWPE_SEL_BITS = (NB_HWPES > 1) ? $clog2(NB_HWPES) : 1

Checklist

• Replace unguarded $clog2(NB_HWPES) occurrences.
• Add/assert NB_HWPES >= 1.
• Verify builds for NB_HWPES in {1, 2, 3, 8, …}.