Disabling printing for a single field within UVM utility macros requires a nuanced approach, as the standard uvm_info and related macros don't offer direct field-specific control. The solution involves understanding how these macros work and strategically employing conditional printing. This guide details several methods, ranging from simple to more advanced, to achieve this goal.
Understanding UVM Utility Macros and Printing
UVM utility macros like uvm_info, uvm_warning, uvm_error, etc., are designed for flexible reporting within your verification environment. They typically take a message string and a verbosity level as arguments. By default, they print to the console based on the configured report severity level. There's no built-in mechanism to selectively suppress printing for individual fields within a structure or class.
Methods to Disable Printing for a Single Field
Here are several strategies to selectively disable printing for a specific field:
1. Conditional Printing with $display and Field Checks
This is the most straightforward approach. Instead of relying directly on the UVM macros, you can use SystemVerilog's $display statement within your transaction or class. You check the field's value and only print if a certain condition is met.
class my_transaction extends uvm_sequence_item;
rand bit [7:0] field_a;
rand bit [15:0] field_b;
function void print_fields();
if (field_a != 0) begin
$display("Field A: %h", field_a);
end
$display("Field B: %h", field_b); // Always prints field B
endfunction
`uvm_object_utils(my_transaction)
endclass
This selectively prints field_a only if it's non-zero. field_b is always printed. This method gives you complete control but requires manually handling printing for each field.
2. Custom Macros or Functions
For better organization and reusability, create custom macros or functions that encapsulate conditional printing logic.
macro print_if_nonzero(field, message);
if (field != 0) begin
$display(message, field);
end
endmacro
class my_transaction extends uvm_sequence_item;
rand bit [7:0] field_a;
rand bit [15:0] field_b;
function void print_fields();
print_if_nonzero(field_a, "Field A: %h");
$display("Field B: %h", field_b);
endfunction
`uvm_object_utils(my_transaction)
endclass
This approach improves code readability and maintainability, especially when dealing with multiple fields requiring conditional printing.
3. Modifying the Report Severity Level (Least Recommended)
This method involves temporarily changing the report severity level before printing specific fields and restoring it afterward. It's generally less preferred because it's less targeted and can affect other reports.
class my_transaction extends uvm_sequence_item;
rand bit [7:0] field_a;
rand bit [15:0] field_b;
function void print_fields();
uvm_report_severity prev_severity = uvm_report_get_severity(); // Save current severity
uvm_report_set_severity(UVM_NONE); // Disable printing temporarily
uvm_info("MY_COMPONENT", $sformatf("Field B: %h", field_b), UVM_LOW); //Will not print
uvm_report_set_severity(prev_severity); // Restore original severity
$display("Field A: %h", field_a); // Will print
endfunction
`uvm_object_utils(my_transaction)
endclass
This approach affects all uvm_info messages with UVM_LOW severity. Only use this if you want to temporarily suppress all messages of a given severity.
Choosing the Right Approach
The optimal method depends on your specific needs and coding style. For simple cases, conditional $display statements are sufficient. For more complex scenarios or better code organization, creating custom macros or functions is recommended. Modifying the report severity level should be avoided unless absolutely necessary due to its broad impact on reporting. Remember to adapt these examples to your specific data types and desired conditions. Prioritize clarity and maintainability in your code.
