This base class defines everything about a phase: behavior, state, and context.
To define behavior, it is extended by UVM or the user to create singleton objects which capture the definition of what the phase does and how it does it. These are then cloned to produce multiple nodes which are hooked up in a graph structure to provide context: which phases follow which, and to hold the state of the phase throughout its lifetime. UVM provides default extensions of this class for the standard runtime phases. VIP Providers can likewise extend this class to define the phase functor for a particular component context as required.
Phase Definition
Singleton instances of those extensions are provided as package variables. These instances define the attributes of the phase (not what state it is in) They are then cloned into schedule nodes which point back to one of these implementations, and calls it’s virtual task or function methods on each participating component. It is the base class for phase functors, for both predefined and user-defined phases. Per-component overrides can use a customized imp.
To create custom phases, do not extend uvm_phase directly: see the three predefined extended classes below which encapsulate behavior for different phase types: task, bottom-up function and top-down function.
Extend the appropriate one of these to create a uvm_YOURNAME_phase class (or YOURPREFIX_NAME_phase class) for each phase, containing the default implementation of the new phase, which must be a uvm_component-compatible delegate, and which may be a null implementation. Instantiate a singleton instance of that class for your code to use when a phase handle is required. If your custom phase depends on methods that are not in uvm_component, but are within an extended class, then extend the base YOURPREFIX_NAME_phase class with parameterized component class context as required, to create a specialized functor which calls your extended component class methods. This scheme ensures compile-safety for your extended component classes while providing homogeneous base types for APIs and underlying data structures.
Phase Context
A schedule is a coherent group of one or mode phase/state nodes linked together by a graph structure, allowing arbitrary linear/parallel relationships to be specified, and executed by stepping through them in the graph order. Each schedule node points to a phase and holds the execution state of that phase, and has optional links to other nodes for synchronization.
The main operations are: construct, add phases, and instantiate hierarchically within another schedule.
Structure is a DAG (Directed Acyclic Graph). Each instance is a node connected to others to form the graph. Hierarchy is overlaid with m_parent. Each node in the graph has zero or more successors, and zero or more predecessors. No nodes are completely isolated from others. Exactly one node has zero predecessors. This is the root node. Also the graph is acyclic, meaning for all nodes in the graph, by following the forward arrows you will never end up back where you started but you will eventually reach a node that has no successors.
Phase State
A given phase may appear multiple times in the complete phase graph, due to the multiple independent domain feature, and the ability for different VIP to customize their own phase schedules perhaps reusing existing phases. Each node instance in the graph maintains its own state of execution.
Phase Handle
Handles of this type uvm_phase are used frequently in the API, both by the user, to access phasing-specific API, and also as a parameter to some APIs. In many cases, the singleton package-global phase handles can be used (eg. connect_ph, run_ph) in APIs. For those APIs that need to look up that phase in the graph, this is done automatically.
| uvm_phase | ||||
| This base class defines everything about a phase: behavior, state, and context. | ||||
| Class Hierarchy | ||||
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| Class Declaration | ||||
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| Construction | ||||
| new | Create a new phase node, with a name and a note of its type name - name of this phase type - task, topdown func or bottomup func | |||
| get_phase_type | Returns the phase type as defined by uvm_phase_type | |||
| State | ||||
| get_state | Accessor to return current state of this phase | |||
| get_run_count | Accessor to return the integer number of times this phase has executed | |||
| find_by_name | Locate a phase node with the specified name and return its handle. | |||
| find | Locate the phase node with the specified phase IMP and return its handle. | |||
| is | returns 1 if the containing uvm_phase refers to the same phase as the phase argument, 0 otherwise | |||
| is_before | Returns 1 if the containing uvm_phase refers to a phase that is earlier than the phase argument, 0 otherwise | |||
| is_after | returns 1 if the containing uvm_phase refers to a phase that is later than the phase argument, 0 otherwise | |||
| Callbacks | ||||
| exec_func | Implements the functor/delegate functionality for a function phase type comp - the component to execute the functionality upon phase - the phase schedule that originated this phase call | |||
| exec_task | Implements the functor/delegate functionality for a task phase type comp - the component to execute the functionality upon phase - the phase schedule that originated this phase call | |||
| Schedule | ||||
| add | Build up a schedule structure inserting phase by phase, specifying linkage | |||
| get_parent | Returns the parent schedule node, if any, for hierarchical graph traversal | |||
| get_full_name | Returns the full path from the enclosing domain down to this node. | |||
| get_schedule | Returns the topmost parent schedule node, if any, for hierarchical graph traversal | |||
| get_schedule_name | Returns the schedule name associated with this phase node | |||
| get_domain | Returns the enclosing domain | |||
| get_imp | Returns the phase implementation for this this node. | |||
| get_domain_name | Returns the domain name associated with this phase node | |||
| Synchronization | ||||
| get_objection | Return the uvm_objection that gates the termination of the phase. | |||
| raise_objection | Raise an objection to ending this phase Provides components with greater control over the phase flow for processes which are not implicit objectors to the phase. | |||
| drop_objection | Drop an objection to ending this phase | |||
| sync and unsync | Add soft sync relationships between nodes | |||
| sync | Synchronize two domains, fully or partially | |||
| unsync | Remove synchronization between two domains, fully or partially | |||
| wait_for_state | Wait until this phase compares with the given state and op operand. | |||
| Jumping | ||||
| jump | Jump to a specified phase. | |||
| jump_all | Make all schedules jump to a specified phase, even if the jump target is local. | |||
| get_jump_target | Return handle to the target phase of the current jump, or null if no jump is in progress. | |||
function new( string name = "uvm_phase", uvm_phase_type phase_type = UVM_PHASE_SCHEDULE, uvm_phase parent = null )
Create a new phase node, with a name and a note of its type name - name of this phase type - task, topdown func or bottomup func
function uvm_phase_type get_phase_type()
Returns the phase type as defined by uvm_phase_type
function int get_run_count()
Accessor to return the integer number of times this phase has executed
function uvm_phase find_by_name( string name, bit stay_in_scope = 1 )
Locate a phase node with the specified name and return its handle. With stay_in_scope set, searches only within this phase’s schedule or domain.
function uvm_phase find( uvm_phase phase, bit stay_in_scope = 1 )
Locate the phase node with the specified phase IMP and return its handle. With stay_in_scope set, searches only within this phase’s schedule or domain.
function bit is( uvm_phase phase )
returns 1 if the containing uvm_phase refers to the same phase as the phase argument, 0 otherwise
function bit is_before( uvm_phase phase )
Returns 1 if the containing uvm_phase refers to a phase that is earlier than the phase argument, 0 otherwise
function bit is_after( uvm_phase phase )
returns 1 if the containing uvm_phase refers to a phase that is later than the phase argument, 0 otherwise
virtual function void exec_func( uvm_component comp, uvm_phase phase )
Implements the functor/delegate functionality for a function phase type comp - the component to execute the functionality upon phase - the phase schedule that originated this phase call
virtual task exec_task( uvm_component comp, uvm_phase phase )
Implements the functor/delegate functionality for a task phase type comp - the component to execute the functionality upon phase - the phase schedule that originated this phase call
function void add( uvm_phase phase, uvm_phase with_phase = null, uvm_phase after_phase = null, uvm_phase before_phase = null )
Build up a schedule structure inserting phase by phase, specifying linkage
Phases can be added anywhere, in series or parallel with existing nodes
| phase | handle of singleton derived imp containing actual functor. by default the new phase is appended to the schedule |
| with_phase | specify to add the new phase in parallel with this one |
| after_phase | specify to add the new phase as successor to this one |
| before_phase | specify to add the new phase as predecessor to this one |
function uvm_phase get_parent()
Returns the parent schedule node, if any, for hierarchical graph traversal
virtual function string get_full_name()
Returns the full path from the enclosing domain down to this node. The singleton IMP phases have no hierarchy.
function uvm_phase get_schedule( bit hier = )
Returns the topmost parent schedule node, if any, for hierarchical graph traversal
function string get_schedule_name( bit hier = )
Returns the schedule name associated with this phase node
function uvm_phase get_imp()
Returns the phase implementation for this this node. Returns null if this phase type is not a UVM_PHASE_LEAF_NODE.
function string get_domain_name()
Returns the domain name associated with this phase node
function uvm_objection get_objection()
Return the uvm_objection that gates the termination of the phase.
virtual function void raise_objection ( uvm_object obj, string description = "", int count = 1 )
Raise an objection to ending this phase Provides components with greater control over the phase flow for processes which are not implicit objectors to the phase.
while(1) begin some_phase.raise_objection(this); ... some_phase.drop_objection(this); end ...
virtual function void drop_objection ( uvm_object obj, string description = "", int count = 1 )
Drop an objection to ending this phase
The drop is expected to be matched with an earlier raise.
Add soft sync relationships between nodes
my_phase.sync(.target(domain)
[,.phase(phase)[,.with_phase(phase)]]);
my_phase.unsync(.target(domain)
[,.phase(phase)[,.with_phase(phase)]]);Components in different schedule domains can be phased independently or in sync with each other. An API is provided to specify synchronization rules between any two domains. Synchronization can be done at any of three levels:
Each kind of synchronization causes the same underlying data structures to be managed. Like other APIs, we use the parameter dot-notation to set optional parameters.
When a domain is synced with another domain, all of the matching phases in the two domains get a ‘with’ relationship between them. Likewise, if a domain is unsynched, all of the matching phases that have a ‘with’ relationship have the dependency removed. It is possible to sync two domains and then just remove a single phase from the dependency relationship by unsyncing just the one phase.
function void sync( uvm_domain target, uvm_phase phase = null, uvm_phase with_phase = null )
Synchronize two domains, fully or partially
| target | handle of target domain to synchronize this one to |
| phase | optional single phase in this domain to synchronize, otherwise sync all |
| with_phase | optional different target-domain phase to synchronize with, otherwise use phase in the target domain |
function void unsync( uvm_domain target, uvm_phase phase = null, uvm_phase with_phase = null )
Remove synchronization between two domains, fully or partially
| target | handle of target domain to remove synchronization from |
| phase | optional single phase in this domain to un-synchronize, otherwise unsync all |
| with_phase | optional different target-domain phase to un-synchronize with, otherwise use phase in the target domain |
task wait_for_state( uvm_phase_state state, uvm_wait_op op = UVM_EQ )
Wait until this phase compares with the given state and op operand. For UVM_EQ and UVM_NE operands, several uvm_phase_states can be supplied by ORing their enum constants, in which case the caller will wait until the phase state is any of (UVM_EQ) or none of (UVM_NE) the provided states.
To wait for the phase to be at the started state or after
wait_for_state(UVM_PHASE_STARTED, UVM_GTE);
To wait for the phase to be either started or executing
wait_for_state(UVM_PHASE_STARTED | UVM_PHASE_EXECUTING, UVM_EQ);
function void jump( uvm_phase phase )
Jump to a specified phase. If the destination phase is within the current phase schedule, a simple local jump takes place. If the jump-to phase is outside of the current schedule then the jump affects other schedules which share the phase.
static function void jump_all( uvm_phase phase )
Make all schedules jump to a specified phase, even if the jump target is local. The jump happens to all phase schedules that contain the jump-to phase, i.e. a global jump.
function uvm_phase get_jump_target()
Return handle to the target phase of the current jump, or null if no jump is in progress. Valid for use during the phase_ended() callback
The uvm_object class is the base class for all UVM data and hierarchical classes.
virtual class uvm_object extends uvm_void
This base class defines everything about a phase: behavior, state, and context.
class uvm_phase extends uvm_object
Create a new phase node, with a name and a note of its type name - name of this phase type - task, topdown func or bottomup func
function new( string name = "uvm_phase", uvm_phase_type phase_type = UVM_PHASE_SCHEDULE, uvm_phase parent = null )
Returns the phase type as defined by uvm_phase_type
function uvm_phase_type get_phase_type()
Accessor to return current state of this phase
function uvm_phase_state get_state()
Accessor to return the integer number of times this phase has executed
function int get_run_count()
Locate a phase node with the specified name and return its handle.
function uvm_phase find_by_name( string name, bit stay_in_scope = 1 )
Locate the phase node with the specified phase IMP and return its handle.
function uvm_phase find( uvm_phase phase, bit stay_in_scope = 1 )
returns 1 if the containing uvm_phase refers to the same phase as the phase argument, 0 otherwise
function bit is( uvm_phase phase )
Returns 1 if the containing uvm_phase refers to a phase that is earlier than the phase argument, 0 otherwise
function bit is_before( uvm_phase phase )
returns 1 if the containing uvm_phase refers to a phase that is later than the phase argument, 0 otherwise
function bit is_after( uvm_phase phase )
Implements the functor/delegate functionality for a function phase type comp - the component to execute the functionality upon phase - the phase schedule that originated this phase call
virtual function void exec_func( uvm_component comp, uvm_phase phase )
Implements the functor/delegate functionality for a task phase type comp - the component to execute the functionality upon phase - the phase schedule that originated this phase call
virtual task exec_task( uvm_component comp, uvm_phase phase )
Build up a schedule structure inserting phase by phase, specifying linkage
function void add( uvm_phase phase, uvm_phase with_phase = null, uvm_phase after_phase = null, uvm_phase before_phase = null )
Returns the parent schedule node, if any, for hierarchical graph traversal
function uvm_phase get_parent()
Returns the full path from the enclosing domain down to this node.
virtual function string get_full_name()
Returns the topmost parent schedule node, if any, for hierarchical graph traversal
function uvm_phase get_schedule( bit hier = )
Returns the schedule name associated with this phase node
function string get_schedule_name( bit hier = )
Returns the enclosing domain
function uvm_domain get_domain()
Returns the phase implementation for this this node.
function uvm_phase get_imp()
Returns the domain name associated with this phase node
function string get_domain_name()
Return the uvm_objection that gates the termination of the phase.
function uvm_objection get_objection()
Objections provide a facility for coordinating status information between two or more participating components, objects, and even module-based IP.
class uvm_objection extends uvm_report_object
Raise an objection to ending this phase Provides components with greater control over the phase flow for processes which are not implicit objectors to the phase.
virtual function void raise_objection ( uvm_object obj, string description = "", int count = 1 )
Drop an objection to ending this phase
virtual function void drop_objection ( uvm_object obj, string description = "", int count = 1 )
Synchronize two domains, fully or partially
function void sync( uvm_domain target, uvm_phase phase = null, uvm_phase with_phase = null )
Remove synchronization between two domains, fully or partially
function void unsync( uvm_domain target, uvm_phase phase = null, uvm_phase with_phase = null )
Wait until this phase compares with the given state and op operand.
task wait_for_state( uvm_phase_state state, uvm_wait_op op = UVM_EQ )
Jump to a specified phase.
function void jump( uvm_phase phase )
Make all schedules jump to a specified phase, even if the jump target is local.
static function void jump_all( uvm_phase phase )
Return handle to the target phase of the current jump, or null if no jump is in progress.
function uvm_phase get_jump_target()