How to extract time value using $vaue$plusargs or an equivalent contruct?

OVM
1

Hi,

I am trying to extract a time delay value from simulation run command.

Below is what I am trying to achieve:

 time switch_startup_delay;

 if (!($value$plusargs("SWITCH_STARTUP_DELAY=%t", switch_startup_delay)))  
   switch_startup_delay = "1us";  

 ovm_report_info(get_type_name(), $psprintf("SW_STARTUP_DELAY: %t", switch_startup_delay));

…
…

#switch_startup_delay;

…
…

I understand that $vaule$plusargs do not accept a time value (%t is not supported), so above code won’t work.

Can someone suggest an alternative of how to achieve above requirement. I do not want to use +define+

Thanks,
San

2

Unfortunately, dealing with physical time units is something that has never been properly addressed in Verilog/SystemVerilog.

One suggestion is to assume your delay will always be expressed as a real number in microseconds.

realtime switch_startup_delay;

if (!($value$plusargs("SWITCH_STARTUP_DELAY=%f", switch_startup_delay)))
    switch_startup_delay = 1;

ovm_report_info(get_type_name(), $psprintf("SW_STARTUP_DELAY: %t", switch_startup_delay));
......
......
#(switch_startup_delay*1us);

Another suggestion is to provide another argument to set the timescale.

realtime switch_startup_delay;
string switch_startup_scale;

if (!($value$plusargs("SWITCH_STARTUP_DELAY=%f", switch_startup_delay)))
    switch_startup_delay = 1;
if ($value$plusargs("SWITCH_STARTUP_SCALE=%s", switch_startup_scale))
    case(switch_startup_scale) // normalize to us
      "s":  switch_startup_delay *= 1s/1us;
      "ms": switch_startup_delay *= 1m/1us;
      "us": switch_startup_delay *= 1us/1us;
      "ps": switch_startup_delay *= 1ps/1us;
      default: $error("bad scale specified");
    endcase

ovm_report_info(get_type_name(), $psprintf("SW_STARTUP_DELAY: %t", switch_startup_delay));
......
......
#(switch_startup_delay*1us);