Verilog-XL compatible simulator options

See vsim for a complete list of simulator options. The options described here are equivalent to Verilog-XL options. Many of these are provided to ease the porting of a design to ModelSim Verilog.

+alt_path_delays

Specify path delays operate in inertial mode by default. In inertial mode, a pending output transition is cancelled when a new output transition is scheduled. The result is that an output may have no more than one pending transition at a time, and that pulses narrower than the delay are filtered. The delay is selected based on the transition from the cancelled pending value of the net to the new pending value. The +alt_path_delays option modifies the inertial mode such that a delay is based on a transition from the current output value rather than the cancelled pending value of the net. This option has no effect in transport mode (see +pulse_e/<percent> and +pulse_r/<percent>).

-l <filename>

By default, the simulation log is written to the file "transcript". The -l option allows you to specify an alternate file.

+maxdelays

This option selects the maximum value in min:typ:max expressions. The default is the typical value. This option has no effect if the min:typ:max selection was determined at compile time.

+mindelays

This option selects the minimum value in min:typ:max expressions. The default is the typical value. This option has no effect if the min:typ:max selection was determined at compile time.

+multisource_int_delays

This option enables multisource interconnect delays with transport delay behavior and pulse handling. ModelSim uses a unique delay value for each driver-to-driven module interconnect path specified in the SDF file. Pulse handling is configured using the +pulse_int_e and +pulse_int_r switches (described below).

+no_cancelled_e_msg

This option disables negative pulse warning messages. By default Vsim issues a warning and then filters negative pulses on specify path delays. You can drive an X for a negative pulse using +show_cancelled_e.

+no_neg_tchk

This option disables negative timing check limits by setting them to zero. By default negative timing check limits are enabled. This is just the opposite of Verilog-XL, where negative timing check limits are disabled by default, and they are enabled with the +neg_tchk option.

+no_notifier

This option disables the toggling of the notifier register argument of the timing check system tasks. By default, the notifier is toggled when there is a timing check violation, and the notifier usually causes a UDP to propagate an X. Therefore, the +no_notifier option suppresses X propagation on timing violations.

+no_path_edge

This option causes ModelSim to ignore the input edge specified in a path delay. The result is that all edges on the input are considered when selecting the output delay. Verilog-XL always ignores the input edges on path delays.

+no_pulse_msg

This option disables the warning message for specify path pulse errors. A path pulse error occurs when a pulse propagated through a path delay falls between the pulse rejection limit and pulse error limit set with the +pulse_r and +pulse_e options. A path pulse error results in a warning message, and the pulse is propagated as an X. The +no_pulse_msg option disables the warning message, but the X is still propagated.

+no_show_cancelled_e

This option filters negative pulses on specify path delays so they don't show on the output. This is the default behavior of Vsim. You can drive an X for a negative pulse using +show_cancelled_e.

+no_tchk_msg

This option disables error messages issued by timing check system tasks when timing check violations occur. However, notifier registers are still toggled and may result in the propagation of X's for timing check violations.

+nosdfwarn

This option disables warning messages during SDF annotation.

+notimingchecks

This option completely disables all timing check system tasks.

+nowarn<mnemonic>

This option disables the class of warning messages specified by <mnemonic>. This option only disables warning messages accompanied by a mnemonic enclosed in square brackets. For example,

# WARNING: test.v(2): [TFMPC] - Too few port connections.

This warning message can be disabled with the +nowarnTFMPC option.

+ntc_warn

This option enables warning messages from the negative timing constraint algorithm. This algorithm attempts to find a set of delays for the timing check delayed net arguments such that all negative limits can be converted to non-negative limits with respect to the delayed nets. If there is no solution for this set of limits, then the algorithm sets one of the negative limits to zero and recalculates the delays. This process is repeated until a solution is found. A warning message is issued for each negative limit set to zero. By default these warnings are disabled.

+pulse_e/<percent>

This option controls how pulses are propagated through specify path delays, where <percent> is a number between 0 and 100 that specifies the error limit as a percentage of the path delay. A pulse greater than or equal to the error limit propagates to the output in transport mode (transport mode allows multiple pending transitions on an output). A pulse less than the error limit and greater than or equal to the rejection limit (see +pulse_r/<percent>) propagates to the output as an X. If the rejection limit is not specified, then it defaults to the error limit. For example, consider a path delay of 10 along with a +pulse_e/80 option. The error limit is 80% of 10 and the rejection limit defaults to 80% of 10. This results in the propagation of pulses greater than or equal to 8, while all other pulses are filtered. Note that you can force specify path delays to operate in transport mode by using the +pulse_e/0 option.

+pulse_int_e/<percent>

This option is analogous to +pulse_e, except it applies to interconnect delays only.

+pulse_int_r/<percent>

This option is analogous to +pulse_r, except it applies to interconnect delays only.

+pulse_r/<percent>

This option controls how pulses are propagated through specify path delays, where <percent> is a number between 0 and 100 that specifies the rejection limit as a percentage of the path delay. A pulse less than the rejection limit is suppressed from propagating to the output. If the error limit is not specified (see +pulse_e (5-71)), then it defaults to the rejection limit.

+pulse_e_style_ondetect

This option selects the "on detect" style of propagating pulse errors (see +pulse_e/<percent>). A pulse error propagates to the output as an X, and the "on detect" style is to schedule the X immediately, as soon as it has been detected that a pulse error has occurred. The "on event" style is the default for propagating pulse errors (see +pulse_e_style_onevent).

+pulse_e_style_onevent

This option selects the "on event" style of propagating pulse errors (see +pulse_e/<percent>). A pulse error propagates to the output as an X, and the "on event" style is to schedule the X to occur at the same time and for the same duration that the pulse would have occurred if it had propagated through normally. The "on event" style is the default for propagating pulse errors.

+sdf_nocheck_celltype

By default, the SDF annotator checks that the CELLTYPE name in the SDF file matches the module or primitive name for the CELL instance. It is an error if the names do not match. The +sdf_nocheck_celltype option disables this error check.

+sdf_verbose

This option displays a summary of the design objects annotated for each SDF file.

+show_cancelled_e

This option causes Vsim to drive a pulse error state ('X') for the duration of negative pulses on specify path delays. By default Vsim filters negative pulses.

+transport_int_delays

By default, interconnect delays operate in inertial mode (pulses smaller than the delay are filtered). The +transport_int_delays option selects transport mode with pulse control for single-source nets (one interconnect path). In transport mode, narrow pulses are propagated through interconnect delays. This option works independent from +multisource_int_delays.

+transport_path_delays

By default, path delays operate in inertial mode (pulses smaller than the delay are filtered). The +transport_path_delays option selects transport mode for path delays. In transport mode, narrow pulses are propagated through path delays. Note that this option affects path delays only, and not primitives. Primitives always operate in inertial delay mode.

+typdelays

This option selects the typical value in min:typ:max expressions. This is the default. This option has no effect if the min:typ:max selection was determined at compile time.

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