User guide

21-38
OpenVera Native Testbench
+ntb_debug_on_error
Stops the simulation when it encounters a simulation error.
Simulation errors involve either an expect error or VCS calling
the error() system task.
+ntb_enable_solver_trace=value
Enables a debug mode that displays diagnostics when VCS
executes a randomize() method call. Allowed values are:
If +ntb_enable_solver_trace is specified without an
argument, the default value is 1. If it is not specified, the default
is 2.
+ntb_enable_solver_trace_on_failure[=value]
Enables a mode that “displays” trace information only when the
VCS constraint solver fails to compute a solution, usually due to
inconsistent constraints. When the value of the option is 2, the
analysis narrows down to the smallest set of inconsistent
constraints, thus aiding the debugging process.
For example, if the constraints are:
x == 0;
x > y;
y < z+w;
x == 5;
y != 6;
If you specify +ntb_enable_solver_trace_on_failure=2
(that is with value “2”), then you will get a report of just the
inconsistent constraints.
Value Description
0 Disables tracing
1 Enables tracing
2 Enables more verbose message in trace