How to Disable Printing in UVM Utility Macros for a Single Field
Disabling printing for a single field within UVM utility macros requires a nuanced approach, as the standard uvm_info and similar macros operate at the transaction or object level. There's no direct flag to silence printing for only specific fields. However, we can achieve this using several methods, each with its pros and cons.
Understanding the Challenge: UVM utility macros (like uvm_info, uvm_warning, uvm_error) typically print information about the entire object or transaction. They don't have built-in mechanisms for selectively suppressing output based on individual field values.
Methods to Disable Printing of a Specific Field:
1. Conditional Printing within the Transaction Class:
This is the most straightforward and recommended approach. Modify your transaction class to conditionally print fields based on a flag or condition.
class my_transaction extends uvm_sequence_item;
rand bit [7:0] field_a;
rand bit [15:0] field_b;
bit print_field_a; // Control flag
`uvm_object_utils(my_transaction)
function void do_print(uvm_printer printer);
super.do_print(printer);
if (print_field_a) begin
printer.print_field("field_a", field_a);
end
endfunction
endclass
Now, you control whether field_a is printed by setting the print_field_a flag before calling any reporting macros. You can extend this to other fields as needed.
2. Custom Reporting Function:
Create a custom function to handle printing within your transaction class. This gives you complete control over the output.
class my_transaction extends uvm_sequence_item;
rand bit [7:0] field_a;
rand bit [15:0] field_b;
`uvm_object_utils(my_transaction)
function void print_selective();
$display("Field B: %h", field_b); // Only print field_b
endfunction
endclass
Use print_selective() instead of relying on default uvm_info macros for this transaction.
3. Preprocessing the Transaction (Less Efficient):
Before passing the transaction to reporting macros, you could create a copy and selectively zero out the fields you don't want printed. This is less efficient and more complex than the previous methods.
4. Modifying Verbosity Levels (Indirect and Less Precise):
While not directly targeting a single field, adjusting the UVM verbosity level (uvm_report_severity) can reduce the overall amount of printed information. This is a blunt instrument and doesn't selectively disable output for specific fields. It's better suited for controlling the overall verbosity of your testbench.
Choosing the Right Method:
The best approach depends on your specific needs and the complexity of your transaction class. For most cases, method 1 (Conditional Printing) provides a clean, efficient, and easily maintainable solution. It allows fine-grained control over which fields are printed without requiring major code restructuring. Method 2 offers more flexibility but introduces more code. Methods 3 and 4 are generally less preferable due to their limitations.
Example Incorporating Method 1:
class my_env extends uvm_env;
my_agent agent;
`uvm_component_utils(my_env)
function new(string name, uvm_component parent);
super.new(name, parent);
agent = new("agent", this);
endfunction
endclass
class my_agent extends uvm_agent;
my_driver driver;
my_monitor monitor;
`uvm_component_utils(my_agent)
function new(string name, uvm_component parent);
super.new(name, parent);
driver = new("driver", this);
monitor = new("monitor", this);
endfunction
endclass
class my_driver extends uvm_driver;
`uvm_component_utils(my_driver)
function new(string name, uvm_component parent);
super.new(name, parent);
endfunction
task run();
my_transaction trans = new();
trans.randomize() with { trans.print_field_a == 0; }; //Disable printing of field_a
uvm_info("DRIVER", $sformatf("Transaction: %s", trans.convert2string()), UVM_LOW);
endtask
endclass
Remember to adapt these examples to your specific transaction and environment structure. Always prioritize clean, well-documented code for maintainability and debugging.
