System Verilog DPI - Properties of Imported Function and Task

Properties of Imported Function and Task

  1. An imported function shall complete their execution instantly and consume zero simulation time. Imported task can consume time.
  2. Imported function can have input, output, and inout arguments.
    • The formal input arguments shall not be modified. If such arguments are changed within a function, the changes shall not be visible outside the function.
    • Imported function shall not assume any initial values of formal output arguments. The initial value of output arguments is undetermined and implementation dependent.
    • Imported function can access the initial value of a formal inout argument. Changes that the Imported function makes to a formal inout argument shall be visible outside the function.
  3. An Imported function shall not free the memory allocated by SystemVerilog code nor expect SystemVerilog code to free memory allocated by Foreign code or (Foreign Compiler).
  4. A call to an Imported task can result in suspension of the currently executing thread. This occurs when an Imported task calls an Exported task, and the Exported task executes a delay control, event control or wait statement. Thus it is possible for an Imported task to be simultaneously active in multiple execution threads.
  5. A Imported function or task can be equip with special properties called pure or context.

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