Virtual Fields

#//—————————————————————————— #// Title: Virtual Register Field Classes #// #// This section defines the virtual field and callback classes. #// #// A virtual field is set of contiguous bits in one or more memory locations. #// The semantics and layout of virtual fields comes from #// an agreement between the software and the hardware, #// not any physical structures in the DUT. #// #//——————————————————————————

class uvm.reg.uvm_vreg_field.UVMVRegField(name='UVMVRegField')

Bases: UVMObject

Class: UVMVRegField

Virtual field abstraction class

A virtual field represents a set of adjacent bits that are logically implemented in consecutive memory locations.

configure(parent, size: int, lsb_pos: int)

get_full_name() → str

Objects possessing hierarchy, such as <uvm_components>, override the default implementation. Other objects might be associated with component hierarchy but are not themselves components. For example, <uvm_sequence #(REQ,RSP)> classes are typically associated with a <uvm_sequencer #(REQ,RSP)>. In this case, it is useful to override get_full_name to return the sequencer’s full name concatenated with the sequence’s name. This provides the sequence a full context, which is useful when debugging.

Returns

The full hierarchical name of this object. The default implementation is the same as <get_name>, as uvm_objects do not inherently possess hierarchy.

Return type

str

get_parent()

get_register()

get_lsb_pos_in_register()

get_n_bits()

create(name='')

Group: Creation

The create method allocates a new object of the same type as this object and returns it via a base uvm_object handle. Every class deriving from uvm_object, directly or indirectly, must implement the create method.

A typical implementation is as follows:

class mytype (UVMObject):
  ...
  def create(self, name=""):
    mytype t = mytype(name)
    return t

Parameters

name (str) – Name of the created object.

Returns

New object.

Return type

obj

get_object_type()

Function: get_object_type

Returns the type-proxy (wrapper) for this object. The uvm_factory’s type-based override and creation methods take arguments of uvm_object_wrapper. This method, if implemented, can be used as convenient means of supplying those arguments. This method is the same as the static get_type method, but uses an already allocated object to determine the type-proxy to access (instead of using the static object).

The default implementation of this method does a factory lookup of the proxy using the return value from get_type_name. If the type returned by get_type_name is not registered with the factory, then a None handle is returned.

For example:

class cmd (UVMObject):
  type_id = UVMObjectRegistry()
  @classmethod
  def type_id get_type(cls):
    return type_id.get()
  def get_object_type(self):
    return cmd.type_id.get()

This function is implemented by the `uvm_*_utils macros, if employed.

Returns:

classmethod get_type()

Returns the type-proxy (wrapper) for this object. The UVMFactory’s type-based override and creation methods take arguments of uvm_object_wrapper. This method, if implemented, can be used as convenient means of supplying those arguments.

The default implementation of this method produces an error and returns None. To enable use of this method, a user’s subtype must implement a version that returns the subtype’s wrapper.

For example:

class cmd(UVMObject):
  type_id = None

  @classmethod
  def get_type(cls):
    return cls.type_id.get()

Then, to use:

factory.set_type_override(cmd.get_type(), subcmd.get_type())

This function is implemented by the uvm_*_utils functions, if employed.

Returns:

get_type_name()

This function returns the type name of the object, which is typically the type identifier enclosed in quotes. It is used for various debugging functions in the library, and it is used by the factory for creating objects.

This function must be defined in every derived class.

A typical implementation is as follows:

class mytype (UVMObject):
  ...
  type_name = "mytype"

  def get_type_name(self):
    return my_type.type_name

We define the type_name static variable to enable access to the type name without need of an object of the class, i.e., to enable access via the scope operator, ~mytype::type_name~.

Returns

Type name of the object.

Return type

str

type_id = <uvm.base.uvm_registry.UVMObjectRegistry object>

type_name = 'UVMVRegField'