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tudor.timi last won the day on July 10 2017

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  1. Seems like a tool limitation. Create a variable of type event and assign the result of the function call to it. Use this variable in the @(...) statement. Note: a better place for this type of question is /https://stackoverflow.com/. Use the system-verilog tag when posting a question.
  2. Regarding point 4: If you want reusable abstractions, one of them is "register/memory accesses". Most hardware blocks use bus transactions to update/query special function registers or memory locations. This is also an abstraction that software/firmware engineers understand. You should look into that. There is so much variation in bus protocols that it's difficult to talk about a universal abstraction. It's also mostly pointless, as when you're talking about verifying bus level aspects, you're interested in the details of that bus protocol.
  3. The blog post you quoted w.r.t. working with types is correct regarding " The correct thing to do from an OOP perspective is to create a virtual function ", but not regarding the further points. In that case, where a protocol uses heterogeneous transaction types (i.e. different kinds have different properties), you're better off using the visitor pattern. The transactions would have a virtual function accept function.
  4. Regarding point number 3, I don't see why the coupling between transaction, driver and monitor is a bad thing. If you treat transactions as mere data classes, the behavior based on this data will have to be implemented in a different class. Should a transaction know how to drive itself and how to monitor itself? Should it also know how to cover itself? What if you have to add another operation, like tracing itself in a waveform viewer? Do you add that to the transaction class too? This violates the single responsibility principle.
  5. Regarding point number 1: Transactions aren't supposed to model traditional classes (not sure what the correct term for such classes is), which contain behavior (i.e. methods) and make use of polymorphism. Transactions are data classes, where you bundle information together to pass around, similar to plain old structs. Contrast the following examples: // Bad design // Using tag classes, where a "tag" field controls the behavior of methods is a code smell class service; direction_e dir; function void do_stuff(); if (dir == READ) do_read(); else do_write(); endfunction endclass // Better design, have two classes interface class service; pure virtual function void do_stuff(); endclass class read_service; virtual function void do_stuff(); // do read stuff endfunction endclass class write_service; // ... endclass In the case above, it makes sense to create different classes for handling reads and writes, because you have a common abstraction (doing stuff), which comes in two different flavors. How would you handle processing different kinds of transactions in a driver (for example) if you had different classes for read and for write? You'd need to cast, which is very frowned upon (at least in the software world). My point about transactions being data classes isn't strictly true w.r.t how they are currently used in the industry. Transactions are also used for randomization, which is a polymorphic operation. Even here though, assuming you want to generate a list of transactions, where some of them are reads, some of them are writes, it will be impossible to do this in a single step if you build up your class hierarchy in such a way that you have a 'read_transaction' class and a 'write_transaction' class. This is because you can't choose an object's type (and I mean from the point of view of the compiler) via randomization. Finally, why is 'direction' the field you choose to specialize on? Assuming you would also have another field in your transaction class called 'sec_mode', which could be either 'SECURE' or 'NONSECURE', would you be inclined to say that you need to create a 'secure_transaction' and a 'non_secure_transaction' because they are different things? Because you also chose to specialize based on direction, would you have 'secure_read_transaction', 'secure_write_transaction', 'nonsecure_read_transaction' and 'nonsecure_write_transaction'? What would happen if you would add another field called 'priviledge_mode', which could be 'PRIVILEGED' or 'UNPRIVILEGED'?
  6. Regarding point number 2: Having both a write_data and a read_data field in the transaction is bad design. A field called data would be sufficient and it would contain that data being transmitted in that transaction, whether it is a read or a write (i.e. regardless of what direction that data flows). The direction field tells you whether you're dealing with read_data or with write_data. Having both fields makes for a pretty difficult to use API if you want to do things irrespective of the direction: if (trans.direction == READ) do_stuff(trans.read_data); else do_stuff(trans.write_data); You'll find your code repeating these conditional statements all over. Contrast this to the case where you only have data: do_stuff(trans.data);
  7. Hi Tudor

    Please can you help me with the RAL register read.

    I have multiple register in my design for which i have generated the RAL model  and i want to read all the register using reg_map ?

      // Get all the registers in map

      foreach(map) begin
        map.read(status, reg_rdata,.map(map), .parent(this));

    I tried doing this but i am getting following error -

    Could not find member 'read' in class 'uvm_reg_map'

    Can you suggest how to do read to all the registers in RAL model.


  8. You're using 'var' as a variable name, but this is an SV keyword. Try naming your variable something different: fork automatic int idx = i; // ! `uvm_do_on(eseq_inst[var], p_sequencer.master_sequencer[var]) join_none
  9. The philosophy behind nested classes is that they have access to private members of the parent class. If you want to do scoping, you're better off using packages (though it's not possible to define a nice hierarchical structure of packages).
  10. Are you trying to compile it on Windows? I don't think QuestaSim supports DPI under Windows (or at least not easily). At the same time, you don't really need to compile UVM itself when running QuestaSim, because the simulator comes packaged with the library and can reference that. * You can change the Makefile to not compile UVM anymore, only the testbench code for the example. * You can also disable DPI by adding the UVM_NO_DPI define (here you might also need to remove the lines from the Makefile that try to compile the C code). * Finally, what's missing there is the path to 'vpi_user.h'. You can add a '-I /path/to/vpi/user/h/inside/questa/installation/' to the GCC call, to tell it explicitly where it can find the file.
  11. The second argument for new(...) is the number of memory locations. You should call: new(..., 2048, 64, ...);
  12. It's not clear in this case what 'valid' means. I don't understand why in your case, when the model would generate '0100', the DUT will respond with '0101' after a '0101'.
  13. The "env.spi_m[0].reg2spi_adapter.*" won't work in there, because the adapter doesn't know under which env it was instantiated. You can check this by calling get_full_name() from the adapter. That's what you need to pass as a context.
  14. When using RAL like this, items aren't created by your agents, but by the adapters interfacing with those agents. If you set up the contexts properly when creating items inside your adapters, it's going to be possible to do instance-based overrides: class spi_adapter extends uvm_reg_adapter; function uvm_sequence_item reg2bus(...); // notice the 'get_full_name()' here spi_item bus_item = spi_item::type_id::create("bus_item", null, get_full_name()); // ... endfunction endclass The extra argument to create(...) sets the context for items create under the adapter as being "<adapter_name>.*". In your environment code, you can set instance overrides like this: class some_tb_env; spi_adapter adapter0; spi_adapter adapter1; function void end_of_elaboration_phase(...); spi_mem_tr::type_id::set_inst_override(spi_mem_tr_0::get_type(), null, "adapter0.*"); spi_mem_tr::type_id::set_inst_override(spi_mem_tr_1::get_type(), null, "adapter1.*"); endfunction endclass Your adapters need to have different names otherwise you won't be able to differentiate between items create by one and ones created by the other. Note: Don't confuse the context passed into create(...) with instance paths of uvm_components. The two are closely related, but aren't the same thing.
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