[source]

Class uvm_pkg::uvm_mem_mam

uvm_pkg::uvm_mem_mam + default_alloc : uvm_mem_mam_policy + convert2string(): string + for_each(): uvm_mem_region + get_memory(): uvm_mem + reconfigure(): uvm_mem_mam_cfg + release_all_regions(): void + release_region(): void + request_region(): uvm_mem_region + reserve_region(): uvm_mem_region uvm_pkg::uvm_mem_mam_policy default_alloc

Collaboration Diagram of uvm_mem_mam

CLASS

uvm_mem_mam

Memory allocation manager

Memory allocation management utility class similar to C's malloc() and free(). A single instance of this class is used to manage a single, contiguous address space.

Variables

Name

Type

Description
default_alloc

uvm_mem_mam_policy

Variable

default_alloc

Region allocation policy

This object is repeatedly randomized when allocating new regions.

Constructors

new(string name, uvm_mem_mam_cfg cfg, uvm_mem mem = null)

Function

new

Create a new manager instance

Create an instance of a memory allocation manager with the specified name and configuration. This instance manages all memory region allocation within the address range specified in the configuration descriptor.

If a reference to a memory abstraction class is provided, the memory locations within the regions can be accessed through the region descriptor, using the uvm_mem_region::read() and uvm_mem_region::write() methods.

Parameters:

Enums

alloc_mode_e

Type

alloc_mode_e

Memory allocation mode

Specifies how to allocate a memory region

GREEDY

Consume new, previously unallocated memory

THRIFTY

Reused previously released memory as much as possible (not yet implemented)

Enum Items:

  • GREEDY

  • THRIFTY

locality_e

Type

locality_e

Location of memory regions

Specifies where to locate new memory regions

BROAD

Locate new regions randomly throughout the address space

NEARBY

Locate new regions adjacent to existing regions

Enum Items:

  • BROAD

  • NEARBY

Functions

reconfigure(uvm_mem_mam_cfg cfg = null)

Function

reconfigure

Reconfigure the manager

Modify the maximum and minimum addresses of the address space managed by the allocation manager, allocation mode, or locality. The number of bytes per memory location cannot be modified once an allocation manager has been constructed. All currently allocated regions must fall within the new address space.

Returns the previous configuration.

if no new configuration is specified, simply returns the current configuration.

Parameters:

cfg (uvm_mem_mam_cfg)

Return type:

uvm_mem_mam_cfg

reserve_region(bit[63:0] start_offset, int unsigned n_bytes, string fname = "", int lineno = 0)

Function

reserve_region

Reserve a specific memory region

Reserve a memory region of the specified number of bytes starting at the specified offset. A descriptor of the reserved region is returned. If the specified region cannot be reserved, null is returned.

It may not be possible to reserve a region because it overlaps with an already-allocated region or it lies outside the address range managed by the memory manager.

Regions can be reserved to create "holes" in the managed address space.

Parameters:

  • start_offset (bit[63:0])

  • n_bytes (int unsigned)

  • fname (string)

  • lineno (int)

Return type:

uvm_mem_region

request_region(int unsigned n_bytes, uvm_mem_mam_policy alloc = null, string fname = "", int lineno = 0)

Function

request_region

Request and reserve a memory region

Request and reserve a memory region of the specified number of bytes starting at a random location. If an policy is specified, it is randomized to determine the start offset of the region. If no policy is specified, the policy found in the uvm_mem_mam::default_alloc class property is randomized.

A descriptor of the allocated region is returned. If no region can be allocated, null is returned.

It may not be possible to allocate a region because there is no area in the memory with enough consecutive locations to meet the size requirements or because there is another contradiction when randomizing the policy.

If the memory allocation is configured to THRIFTY or NEARBY , a suitable region is first sought procedurally.

Parameters:
Return type:

uvm_mem_region

release_region(uvm_mem_region region)

Function

release_region

Release the specified region

Release a previously allocated memory region. An error is issued if the specified region has not been previously allocated or is no longer allocated.

Parameters:

region (uvm_mem_region)

release_all_regions()

Function

release_all_regions

Forcibly release all allocated memory regions.

convert2string()

Function

convert2string

Image of the state of the manager

Create a human-readable description of the state of the memory manager and the currently allocated regions.

for_each(bit reset = 0)

Function

for_each

Iterate over all currently allocated regions

If reset is TRUE , reset the iterator and return the first allocated region. Returns null when there are no additional allocated regions to iterate on.

Parameters:

reset (bit)

Return type:

uvm_mem_region

get_memory()

Function

get_memory

Get the managed memory implementation

Return the reference to the memory abstraction class for the memory implementing the locations managed by this instance of the allocation manager. Returns null if no memory abstraction class was specified at construction time.

Return type:

uvm_mem