Time-based encryption in simulations?

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I've tested $system calls on Modelsim SE and it's supported, but I can't say about the other flavors and simulators.

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The SystemVerilog spec defines system on page 542, Section 20.18.1.

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$system makes a call to the C function system(). The C function executes the argument passed to it as if the argument was executed from the terminal. $system can be called as either a task or a function. When called as a function, it returns the return value of the call to system() with data type int. If $system is called with no string argument, the C function system() will be called with the NULL string.

The example below calls $system as a task to rename a file.

module top;

initial $system("mv design.v adder.v");

endmodule

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Looks like you've got a way of getting the time without writing any extra code or using PLI.

Since this is part of the spec, other simulators should implement it.

For Quartus, just put a synthesis directive around the $system call, and implement your hardware counter kill logic instead.

Cheers,

Dave