uvm_callback

uvm.base.uvm_callback.ALL_TYPES = None

Callbacks Classes

This section defines the classes used for callback registration, management, and user-defined callbacks.

uvm.base.uvm_callback.o2str(ordering)

class uvm.base.uvm_callback.UVMTypeIDBase

Bases: object

Simple typeid interface. Need this to set up the base-super mapping. This is similar to the factory, but much simpler. The idea of this interface is that each object type T has a typeid that can be used for mapping type relationships. This is not a user visible class.

typename = ''

typeid_map: Dict[UVMTypeIDBase, UVMCallbacks] = {<uvm.base.uvm_callback.UVMTypeID object>: <uvm.base.uvm_callback.UVMCallbacks object>}

type_map: Dict[UVMCallbacksBase, UVMTypeIDBase] = {<uvm.base.uvm_callback.UVMCallbacksBase object>: <uvm.base.uvm_callback.UVMTypeID object>, None: <uvm.base.uvm_callback.UVMTypeID object>}

class uvm.base.uvm_callback.UVMTypeID

Bases: UVMTypeIDBase

m_b_inst = <uvm.base.uvm_callback.UVMTypeID object>

classmethod get()

class uvm.base.uvm_callback.UVMCallbacksBase(name)

Bases: UVMObject

Base class singleton that holds generic queues for all instance specific objects. This is an internal class. This class contains a global pool that has all of the instance specific callback queues in it. All of the typewide callback queues live in the derivative class UVMTypedCallbacks#(T). This is not a user visible class.

This class holds the class inheritance hierarchy information (super types and derivative types).

Note, all derivative uvm_callbacks#() class singletons access this global m_pool object in order to get access to their specific instance queue.

m_b_inst = None

m_pool = <uvm.base.uvm_pool.UVMPool object>

m_tracing = 1

classmethod m_initialize()

m_am_i_a(obj)

m_is_for_me(cb: UVMCallback)

m_is_registered(obj, cb)

m_get_tw_cb_q(obj, CB=None)

m_add_tw_cbs(cb, ordering)

m_delete_tw_cbs(cb)

check_registration(obj, cb)

Check registration. To test registration, start at this class and work down the class hierarchy. If any class returns true then the pair is legal.

Parameters

• obj (UVMObject) –

• cb (UVMCallback) –

Returns

True if obj is registered, False otherwise

Return type

bool

classmethod get_first(itr, obj, CB=None) → Optional[UVMCallback]

Returns the first enabled callback of type CB which resides in the queue for obj. If obj is None then the typewide queue for T is searched. itr is the iterator it will be updated with a value that can be supplied to get_next to get the next callback object.

If the queue is empty then None is returned.

The iterator class uvm_callback_iter may be used as an alternative, simplified, iterator interface.

Parameters

• itr –

• obj –

• CB – Type of the callback

Returns

First found callback.

Return type

UVMCallback

class uvm.base.uvm_callback.UVMTypedCallbacks(name, T=None)

Bases: UVMCallbacksBase

m_tw_cb_q: List[UVMCallback] = []

m_typename = ''

m_t_inst = <uvm.base.uvm_callback.UVMTypedCallbacks object>

classmethod m_initialize()

m_am_i_a(obj)

Type checking interface: is given obj of type T? :param obj:

Returns:

m_get_tw_cb_q(obj, CB=None)

Getting the typewide queue :param obj: :param CB:

Returns:

classmethod m_cb_find(q, cb)

classmethod m_cb_find_name(q, name, where)

static function int m_cb_find_name(uvm_queue#(uvm_callback) q, string name, string where)

Parameters

• cls –

• q –

• name –

• where –

Returns:

m_add_tw_cbs(cb, ordering)

#For a typewide callback, need to add to derivative types as well. virtual function void m_add_tw_cbs(uvm_callback cb, uvm_apprepend ordering)

Parameters

• cb –

• ordering –

classmethod display(obj=None)

static function void display(T obj=None)

Parameters

• cls –

• obj –

class uvm.base.uvm_callback.UVMCallbacks(name='uvm_callbacks', T=None, CB=None)

Bases: UVMTypedCallbacks

The UVMCallbacks class provides a base class for implementing callbacks, which are typically used to modify or augment component behavior without changing the component class. To work effectively, the developer of the component class defines a set of “hook” methods that enable users to customize certain behaviors of the component in a manner that is controlled by the component developer. The integrity of the component’s overall behavior is intact, while still allowing certain customizable actions by the user.

To enable compile-time type-safety, the class is parameterized on both the user-defined callback interface implementation as well as the object type associated with the callback. The object type-callback type pair are associated together using the UVMRegisterCb macro to define a valid pairing; valid pairings are checked when a user attempts to add a callback to an object.

To provide the most flexibility for end-user customization and reuse, it is recommended that the component developer also define a corresponding set of virtual method hooks in the component itself. This affords users the ability to customize via inheritance/factory overrides as well as callback object registration. The implementation of each virtual method would provide the default traversal algorithm for the particular callback being called. Being virtual, users can define subtypes that override the default algorithm, perform tasks before and/or after calling super.<method> to execute any registered callbacks, or to not call the base implementation, effectively disabling that particular hook. A demonstration of this methodology is provided in an example included in the kit.

m_inst = <uvm.base.uvm_callback.UVMCallbacks object>

m_typeid = <uvm.base.uvm_callback.UVMTypeID object>

m_cb_typeid = <uvm.base.uvm_callback.UVMTypeID object>

m_typename = ''

m_cb_typename = ''

reporter = <uvm.base.uvm_report_object.UVMReportObject object>

m_base_inst = <uvm.base.uvm_callback.UVMCallbacks object>

classmethod get() → UVMCallbacks

Get the singleton instance of the class

Returns

The singleton instance of the class

Return type

UVMCallbacks

classmethod m_register_pair(tname='', cbname='', T=None)

Register valid callback type

Parameters

• tname (str) –

• cbname (str) –

• T –

• ALL_TYPES –

Returns:

classmethod add(obj, cb, ordering=0)

classmethod get_obj_and_typename(obj)

classmethod m_get_q(obj, CB=None)

#————————– Group: Iterator Interface #————————–

This set of functions provide an iterator interface for callback queues. A facade class, uvm_callback_iter is also available, and is the generally preferred way to iterate over callback queues. :param cls: :param obj: :param CB:

Returns:

classmethod get_first(itr, obj, CB=None)

Function: get_first

Returns the first enabled callback of type CB which resides in the queue for obj. If obj is None then the typewide queue for T is searched. itr is the iterator it will be updated with a value that can be supplied to get_next to get the next callback object.

If the queue is empty then None is returned.

The iterator class uvm_callback_iter may be used as an alternative, simplified, iterator interface.

Parameters

• cls –

• itr –

• obj –

• CB –

Returns:

classmethod get_last(itr, obj, CB=None)

Function: get_last

Returns the last enabled callback of type CB which resides in the queue for obj. If obj is None then the typewide queue for T is searched. itr is the iterator it will be updated with a value that can be supplied to get_prev to get the previous callback object.

If the queue is empty then None is returned.

The iterator class uvm_callback_iter may be used as an alternative, simplified, iterator interface.

static function CB get_last (ref int itr, input T obj)

Parameters

• cls –

• itr –

• obj –

• CB –

Returns:

classmethod get_next(itr, obj, CB=None)

Function: get_next

Returns the next enabled callback of type CB which resides in the queue for obj, using itr as the starting point. If obj is None then the typewide queue for T is searched. itr is the iterator; it will be updated with a value that can be supplied to get_next to get the next callback object.

If no more callbacks exist in the queue, then None is returned. get_next will continue to return None in this case until get_first or get_last has been used to reset the iterator.

The iterator class uvm_callback_iter may be used as an alternative, simplified, iterator interface.

static function CB get_next (ref int itr, input T obj)

Parameters

• cls –

• itr –

• obj –

• CB –

Returns:

classmethod get_prev(itr, obj, CB=None)

Function: get_prev

Returns the previous enabled callback of type CB which resides in the queue for obj, using itr as the starting point. If obj is None then the typewide queue for T is searched. itr is the iterator; it will be updated with a value that can be supplied to get_prev to get the previous callback object.

If no more callbacks exist in the queue, then None is returned. get_prev will continue to return None in this case until get_first or get_last has been used to reset the iterator.

The iterator class uvm_callback_iter may be used as an alternative, simplified, iterator interface.

static function CB get_prev (ref int itr, input T obj)

Parameters

• cls –

• itr –

• obj –

• CB –

Returns:

classmethod display(obj=None)

#————- Group: Debug #————-

Function: display

This function displays callback information for obj. If obj is None, then it displays callback information for all objects of type T, including typewide callbacks.

static function void display(T obj=None)

Parameters

• cls –

• obj –

m_t_inst = <uvm.base.uvm_callback.UVMCallbacks object>

class uvm.base.uvm_callback.UVMCallbackIter(obj, CB=None)

Bases: object

The ~uvm_callback_iter~ class is an iterator class for iterating over callback queues of a specific callback type. The typical usage of the class is:

uvm_callback_iter#(mycomp,mycb) iter = new(this)
for(mycb cb = iter.first(); cb is not None; cb = iter.next())
  cb.dosomething()

The callback iteration macros, <`uvm_do_callbacks> and <`uvm_do_callbacks_exit_on> provide a simple method for iterating callbacks and executing the callback methods.

first() → Optional[UVMCallback]

Function: first

Returns the first valid (enabled) callback of the callback type (or a derivative) that is in the queue of the context object. If the queue is empty then None is returned. Returns:

last() → Optional[UVMCallback]

Function: last

Returns the last valid (enabled) callback of the callback type (or a derivative) that is in the queue of the context object. If the queue is empty then None is returned. Returns:

next() → Optional[UVMCallback]

Returns the next valid (enabled) callback of the callback type (or a derivative) that is in the queue of the context object. If there are no more valid callbacks in the queue, then None is returned.

Returns:

prev() → Optional[UVMCallback]

Returns the previous valid (enabled) callback of the callback type (or a derivative) that is in the queue of the context object. If there are no more valid callbacks in the queue, then None is returned.

Returns:

get_cb() → Optional[UVMCallback]

Returns the last callback accessed via a first() or next() call.

Returns:

class uvm.base.uvm_callback.UVMCallback(name='uvm_callback')

Bases: UVMObject

The UVMCallback class is the base class for user-defined callback classes. Typically, the component developer defines an application-specific callback class that extends from this class. In it, he defines one or more virtual methods, called a ~callback interface~, that represent the hooks available for user override.

Methods intended for optional override should not be declared ~pure.~ Usually, all the callback methods are defined with empty implementations so users have the option of overriding any or all of them.

The prototypes for each hook method are completely application specific with no restrictions.

reporter = <uvm.base.uvm_report_object.UVMReportObject object>

callback_mode(on=-1)

Enable/disable callbacks (modeled like rand_mode and constraint_mode).

Parameters

on –

Returns:

is_enabled()

Returns 1 if the callback is enabled, 0 otherwise.

Returns

1 if the callback is enabled, 0 otherwise.

Return type

bool

type_name = 'uvm_callback'

get_type_name()

Returns the type name of this callback object.

Returns

Type name of this callback object.

Return type

str