Below is a discussion of the timing-related command line build options. For a full description of these options, please consult the Specify blocks chapter of the Verilog LRM.

Simx supports two methods of pulse filtering: On-Event and On-Detect. On-event filters pulses so that transitions to and from X occur after the delay for the originally scheduled transition and the new output state respectively. On-Detect is more conservative; it filters pulses so that the transition to the X state occurs immediately on detection of the pulse error. This X state then remains until the originally calculated delay for the new output state.

The On-Detect method allows more pessimism when filtering pulses to the X state, producing a longer X region. On-Detect filtering allows for a better understanding of the outputs caused by two or more changing inputs that result in output scheduling conflicts, but has more impact on simulation speed and yields more pessimistic results.

The next two options below control which method of pulse-filtering is used:

+epulse_ondetect

Enables On-Detect filtering of error pulses. This option extends the e state back to the edge of the event that caused the pulse to occur. See section 5.12 for the differences between on-detect and on-event pulse filtering.

+epulse_onevent

Enables On-Event filtering of error pulses. See section 5.12 for the differences between on-detect and on-event pulse filtering.

+epulse_neg

Filter canceled events (negative pulses) to the e state. This option makes canceled events visible. Using this option overrides any showcancelled and noshowcancelled settings in specify blocks.

+epulse_noneg

Do not filter canceled events (negative pulses) to the e state. Using this option overrides any showcancelled and noshowcancelled settings in specify blocks.

+notimingchecks

Do not execute timing checks

+notchkmsg

Do not display timing check warning messages.

+no_notifier

Ignore notifiers in timing checks.

+nospecify

Ignores timing checks, path delays, and $sdf_annotate calls.

+pathpulse

Enable PATHPULSE$ declarations. These declarations set the module path pulse control on a specific module or on specific paths within modules.

+mindelays, +typdelays, +maxdelays

Selects minimum, typical, or maximum delays for simulation. +typdelays is the default option. If more than one of these flags is specified, only the last will be used.

Pulse and Reject Percentage Options

To maintain compatibility with other simulators, the pulse options specify the flag name and a percentage separated by a / rather than a space (e.g. +pulse_e/10).

+pulse_e/error_percent

Set the percentage of delay for the pulse error limit for both module paths and interconnect. In Cadence ncsim, this option applies only to module paths if the -pulse_int_e option is also used. To achieve the same timing using simx, use instead the +pulse_path_e option described in the ModelSim-compatibility section below.

+pulse_r/reject_percent

Sets the percentage of delay for the pulse reject limit for both module paths and interconnect. In Cadence ncsim, this option applies only to module paths if the -pulse_int_r option is also used. To achieve the same timing using simx, use instead the +pulse_path_r option described in the ModelSim-compatibility section below.

+pulse_int_e/error_percent

Sets the percentage of delay for the pulse error limit only for interconnects.

+pulse_int_r/reject_percent

Sets the percentage of delay for the pulse reject limit only for interconnects.

Flags for ModelSim-Compatible Timing

+pulse_path_e/error_percent

Sets the percentage of delay for the pulse error limit only for specify paths.

+pulse_path_r/reject_percent

Sets the percentage of delay for the pulse reject limit only for specify paths.

+transport_path_delays

Specify path delays will operate as transport delays (shorter pulses will be propagated).