Each of UVM’s policy classes perform a specific task for uvm_object-based objects: printing, comparing, recording, packing, and unpacking. They are implemented separately from uvm_object so that users can plug in different ways to print, compare, etc. without modifying the object class being operated on. The user can simply apply a different printer or compare “policy” to change how an object is printed or compared.
Each policy class includes several user-configurable parameters that control the operation. Users may also customize operations by deriving new policy subtypes from these base types. For example, the UVM provides four different uvm_printer-based policy classes, each of which print objects in a different format.
- uvm_printer - performs deep printing of uvm_object-based objects. The UVM provides several subtypes to uvm_printer that print objects in a specific format: uvm_table_printer, uvm_tree_printer, and uvm_line_printer. Each such printer has many configuration options that goven what and how object members are printed.
- uvm_comparer - performs deep comparison of uvm_object-based objects. Users may configure what is compared and how miscompares are reported.
- uvm_recorder - performs the task of recording uvm_object-based objects to a transaction data base. The implementation is vendor-specific.
- uvm_packer - used to pack (serialize) and unpack uvm_object-based properties into bit, byte, or int arrays and back again.
|Each of UVM’s policy classes perform a specific task for uvm_object-based objects: printing, comparing, recording, packing, and unpacking. |