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C++ Object life cycle through SV DPI

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Hi all,

I have a C++ Object life cycle through SV DPI problem.

For example, I have a C++ reference model class named ALU.  Only one public function revealed to client (e.g. ALU::ALU_EXEC) and was encapsulated in DPI(ALU_EXEC_DPI) . And there are two types of ALU commands was entered to ALU::ALU_EXEC. One is setup ALU parameters (i.e. setup the ALU class private member) , the other is calculating the result.
 
The question is when I leave DPI, the ALU object is eliminated and all the setup parameter is cleared, right? So can I keep a C++ Object even after I leave DPI (i.e. is the C++ Object life cycle only as long as DPI call life cycle).

My friend suggest me to return all the ALU parameter out to SV and re-enter these parameters to ALU through ALU_EXEC_DPI when I call the ALU reference model. But it may break the model encapsulation :(

May be my question is not very clear and any suggestions are welcome!
Davy




Originally posted in cdnusers.org by davyzhu
Parents

  • Ok,

    Now, do not use the task. Use function instead.

    You will have one more input to your input argument list, e.g. status.

    //---SV file
    import “DPI-C” context alu_run = function int alu_run(...);
    always @(status)
    alu_run(clk, opcode,a, b, result,$realtime, status);
    //---

    Now, untill and unless you pass status value '2' the C++ shouldn't exit. This way the C++ would be alive and you can continue the simulation. At the time you want to exit, pass the value '2' to the C++. For the normal sim, you can pass the value '1'.

    Also, i would like to suggest you to use two tasks for "constructor" and "destructor" and a function for the alu_run. But one thing is clear that even you are out of the alu_run function the values would still be retained, unless you enter it again and initialize the same.

    I guess, i am showing you the right path.

    -Vivek


    Originally posted in cdnusers.org by prasad_vc
Reply

  • Ok,

    Now, do not use the task. Use function instead.

    You will have one more input to your input argument list, e.g. status.

    //---SV file
    import “DPI-C” context alu_run = function int alu_run(...);
    always @(status)
    alu_run(clk, opcode,a, b, result,$realtime, status);
    //---

    Now, untill and unless you pass status value '2' the C++ shouldn't exit. This way the C++ would be alive and you can continue the simulation. At the time you want to exit, pass the value '2' to the C++. For the normal sim, you can pass the value '1'.

    Also, i would like to suggest you to use two tasks for "constructor" and "destructor" and a function for the alu_run. But one thing is clear that even you are out of the alu_run function the values would still be retained, unless you enter it again and initialize the same.

    I guess, i am showing you the right path.

    -Vivek


    Originally posted in cdnusers.org by prasad_vc
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