icache_checker: default WAY_WIDHT is inconsistent with the LINES_256 code path

[Shivam-Shukla0]

Description

• Summary:
  sargantana_icache_checker declares parameter int unsigned WAY_WIDHT = 32*8 (256), but the LINES_256 == 1'b1 branch of chunk_sel indexes data[511:256], which needs 512. With the module's own defaults that selection is out of range.

  In practice sargantana_top_icache.sv:393 passes WAY_WIDHT from the package (512 in the default configuration), and LINES_256 defaults to 1'b0, so the branch is unreachable as integrated today. But instantiating the checker with LINES_256 = 1'b1 without also overriding WAY_WIDHT would read out of range rather than failing at elaboration.

Environment

• Details:
  main branch, Verilator 5.048. Linting sargantana_icache_checker.sv standalone (module defaults) reports:

  %Warning-SELRANGE: sargantana_icache_checker.sv:79: Selection index out of range: 511:256 outside 255:0
  %Warning-SELRANGE: sargantana_icache_checker.sv:95: Selection index out of range: 383:256 outside 255:0
  %Warning-SELRANGE: sargantana_icache_checker.sv:96: Selection index out of range: 511:384 outside 255:0

Hypothesis / Comments

• Additional Information:
  Would you prefer the default raised to 64*8 so it matches the widest path the module supports, or is the intent that LINES_256 is only ever set together with an explicit WAY_WIDHT? In the latter case an elaboration-time assertion might be clearer than leaving it implicit. Happy to send a PR either way.