Limit number of jobs for verilator

src/fpga_sim/fpga_sim.py

@@ -22,6 +22,7 @@ def fpga_sim_main():
 
     parser.add_argument("yaml")
     parser.add_argument("test_name", nargs="?")
+    parser.add_argument("-j", "--jobs", default=1)
 
     args = parser.parse_args()
 
@@ -78,7 +79,9 @@ def fpga_sim_main():
     sim = os.getenv("SIM", "verilator")
     runner = get_runner(sim)
 
-    os.environ["MAKEFLAGS"] = "-j"
+    jobs = args.jobs
+    print(jobs)
+    os.environ["MAKEFLAGS"] = f"-j{jobs}"
 
     tests_to_run = []
 
@@ -107,3 +110,4 @@ def fpga_sim_main():
         sys.path.append(test["base_path"])
 
         runner.test(hdl_toplevel=test["toplevel"], test_module=test["modules"], waves=test["waves"], results_xml=result_xml)
+