svt_atb_transaction Class Reference

This is the base transaction type which contains all the physical attributes of the transaction like id, data, burst length, etc. It also provides the timing information of the transaction to the master & slave transactors, that is, delays for valid and ready signals with respect to some reference events.

The svt_atb_transaction also contains a handle to configuration object of type svt_atb_port_configuration , which provides the configuration of the port on which this transaction would be applied. The port configuration is used during randomizing the transaction.

Member Function Documentation

function void
svt_atb_transaction::add_databeat

( bit [SVT_ATB_MAX_DATA_WIDTH-1:0] databeat )

adds this databeat as data bytes to current data_byte array.

databeat - Data beat that needs to be added to current transaction

function void
svt_atb_transaction::add_databeat_array

( bit [SVT_ATB_MAX_DATA_WIDTH-1:0] databeat [] )

adds array of databeats as data bytes to current data_byte array.

databeat - Array containing set of databeats

function bit
svt_atb_transaction::decode_prop_val

( string prop_name , bit [1023:0] prop_val , ref string prop_val_string , input svt_pattern_data :: type_enum typ )

Simple utility used to convert 'bit [1023:0]' property value representation into its equivalent string property value representation. Extended to support decoding of enum values.

prop_name - The name of the property being encoded.

prop_val_string - The string describing the value to be encoded.

prop_val - The bit vector encoding of prop_val_string.

typ - Optional field type used to help in the encode effort.

Return values - The enum value corresponding to the desc.

Superseded functions
	svt_sequence_item_base :: decode_prop_val
	svt_sequence_item :: decode_prop_val

function svt_pattern
svt_atb_transaction::do_allocate_pattern

( )

This method allocates a pattern containing svt_pattern_data instances for all of the primitive data fields in the object. The name is set to the corresponding field name, the value is set to 0.

Return values - An svt_pattern instance containing entries for all of the data fields.

Superseded functions
	svt_sequence_item_base :: do_allocate_pattern
	svt_sequence_item :: do_allocate_pattern
Superseding functions
	svt_atb_master_transaction :: do_allocate_pattern
	svt_atb_slave_transaction :: do_allocate_pattern

function bit
svt_atb_transaction::do_compare

( ovm_object rhs , ovm_comparer comparer )

Compares the object with rhs..

rhs - Object to be compared against.

comparer - TBD

Superseded functions
	ovm_object :: do_compare
	svt_sequence_item_base :: do_compare
	svt_sequence_item :: do_compare
Superseding functions
	svt_atb_master_transaction :: do_compare
	svt_atb_slave_transaction :: do_compare

function void
svt_atb_transaction::do_copy

( ovm_object rhs )

Extend the copy method to take care of the transaction fields and cleanup the exception xact pointers.

rhs - Source object to be copied.

Superseded functions
	ovm_object :: do_copy
	ovm_transaction :: do_copy
	svt_sequence_item_base :: do_copy
	svt_sequence_item :: do_copy
Superseding functions
	svt_atb_master_transaction :: do_copy
	svt_atb_slave_transaction :: do_copy

function bit
svt_atb_transaction::do_is_valid

( bit silent = 1, int kind = RELEVANT )

Does a basic validation of this transaction object

Superseded functions
	svt_sequence_item_base :: do_is_valid
	svt_sequence_item :: do_is_valid
Superseding functions
	svt_atb_master_transaction :: do_is_valid
	svt_atb_slave_transaction :: do_is_valid

function bit
svt_atb_transaction::encode_prop_val

( string prop_name , string prop_val_string , ref bit [1023:0] prop_val , input svt_pattern_data :: type_enum typ )

Simple utility used to convert string property value representation into its equivalent 'bit [1023:0]' property value representation. Extended to support encoding of enum values.

prop_name - The name of the property being encoded.

prop_val_string - The string describing the value to be encoded.

prop_val - The bit vector encoding of prop_val_string.

typ - Optional field type used to help in the encode effort.

Return values - The enum value corresponding to the desc.

Superseded functions
	svt_sequence_item_base :: encode_prop_val
	svt_sequence_item :: encode_prop_val

function int
svt_atb_transaction::get_burst_length

( )

Gets the number of beats of data to be sent.

function int
svt_atb_transaction::get_byte_count

( )

Returns the total number of bytes transferred in this transaction

Return values - The total number of bytes transferred in this transaction

function bit [SVT_ATB_MAX_DATA_WIDTH-1:0]
svt_atb_transaction::get_databeat

( int curr_beat = -1 )

This method returns complete data-beat based on databus width specified in port-configuration, from data_byte array. While returning data-beat it considers current_data_beat_num to choose which bytes from data_byte array will be packed. However, if this method is called with a non-negative value then it uses that value as current data beat number and chooses data bytes from data_byte accordingly. It places bytes with lowest index to LSB postion of returning databeat.

curr_beat - Specifies beat number for which data need to be returned.

function string
svt_atb_transaction::get_mcd_class_name

( )

Returns the class name for the object used for logging.

Superseded functions
	svt_sequence_item_base :: get_mcd_class_name
Superseding functions
	svt_atb_master_transaction :: get_mcd_class_name
	svt_atb_slave_transaction :: get_mcd_class_name

function svt_pa_object_data
svt_atb_transaction::get_pa_obj_data

( string uid = "", string typ = "", string parent_uid = "", string channel = "" )

This method returns PA object which contains the PA header information for XML or FSDB.

uid - Optional string indicating the unique identification value for object. If not provided uses the 'get_uid' method to retrieve the value.

typ - Optional string indicating the 'type' of the object. If not provided uses the type name for the class.

parent_uid - Optional string indicating the UID of the object's parent. If not provided the method assumes there is no parent.

channel - Optional string indicating an object channel. If not provided the method assumes there is no channel.

Return values - The requested object block description.

Superseded functions
	svt_sequence_item_base :: get_pa_obj_data
	svt_sequence_item :: get_pa_obj_data
Superseding functions
	svt_atb_master_transaction :: get_pa_obj_data
	svt_atb_slave_transaction :: get_pa_obj_data

function bit
svt_atb_transaction::get_prop_val

( string prop_name , ref bit [1023:0] prop_val , input int array_ix , ref svt_sequence_item_base data_obj )

HDL Support: For read access to public data members of this class.

Superseded functions
	svt_sequence_item_base :: get_prop_val
	svt_sequence_item :: get_prop_val
Superseding functions
	svt_atb_master_transaction :: get_prop_val
	svt_atb_slave_transaction :: get_prop_val

function bit
svt_atb_transaction::is_trigger

( )

Returns 1 if current Transaction carries Trigger message from Trace Source

function void
svt_atb_transaction::new

( string name = "svt_atb_transaction", svt_atb_port_configuration port_cfg_handle = null )

CONSTUCTOR: Create a new transaction instance, passing the appropriate argument values to the parent class.

name - Instance name of the transaction

Superseding functions
	svt_atb_master_transaction :: new
	svt_atb_slave_transaction :: new

function void
svt_atb_transaction::pack_data_to_byte_stream

( input bit [SVT_ATB_MAX_DATA_WIDTH-1:0] data_to_pack [], output bit [7:0] packed_data [] )

Returns the data in the data_to_pack[] field as a byte stream based on the burst_type. The assumption is that either data[] or cache_write_data[] fields of this class have been passed as arguments to data_to_pack[] field. In the case of WRAP bursts the data is returned such that packed_data[0] corresponds to the data for the wrap boundary. In the case of INCR bursts, the data as passed in data_to_pack[] is directly packed to packed_data[].

data_to_pack - Data to be packed

packed_data - [] Output byte stream with packed data

function string
svt_atb_transaction::psdisplay_short

( string prefix = "", bit hdr_only = 0 )

Returns a string (with no line feeds) that reports the essential contents of the packet generally necessary to uniquely identify that packet.

prefix - (Optional: default = "") The string given in this argument becomes the first item listed in the value returned. It is intended to be used to identify the transactor (or other source) that requested this string. This argument should be limited to 8 characters or less (to accommodate the fixed column widths in the returned string). If more than 8 characters are supplied, only the first 8 characters are used.

hdr_only - (Optional: default = 0) If this argument is supplied, and is '1', the function returns a 3-line table header string, which indicates which packet data appears in the subsequent columns. If this argument is '1', the prefix argument becomes the column label for the first header column (still subject to the 8 character limit).

Superseded functions
	svt_sequence_item :: psdisplay_short
Superseding functions
	svt_atb_master_transaction :: psdisplay_short

function int
svt_atb_transaction::reasonable_constraint_mode

( bit on_off )

Method to turn reasonable constraints on/off as a block.

Superseded functions
	svt_sequence_item_base :: reasonable_constraint_mode
Superseding functions
	svt_atb_master_transaction :: reasonable_constraint_mode
	svt_atb_slave_transaction :: reasonable_constraint_mode

function void
svt_atb_transaction::set_cfg

( svt_atb_port_configuration cfg )

Sets the configuration property

Superseding functions
	svt_atb_master_transaction :: set_cfg

function void
svt_atb_transaction::set_databeat

( int curr_beat = -1, bit [SVT_ATB_MAX_DATA_WIDTH-1:0] databeat )

This method returns complete data-beat to corresponding data_byte array locations. It starts populating associated data_byte array locations from lowest indices with LSB bytes of databeat.

curr_beat - Specifies beat number for which data need to be stored.

function bit
svt_atb_transaction::set_prop_val

( string prop_name , bit [1023:0] prop_val , int array_ix )

HDL Support: For write access to public data members of this class.

Superseded functions
	svt_sequence_item_base :: set_prop_val
	svt_sequence_item :: set_prop_val
Superseding functions
	svt_atb_master_transaction :: set_prop_val
	svt_atb_slave_transaction :: set_prop_val

function void
svt_atb_transaction::unpack_byte_stream_to_data

( input bit [7:0] data_to_unpack [], output bit [SVT_ATB_MAX_DATA_WIDTH-1:0] unpacked_data [] )

Unpacks the data in data_to_unpack[] into utemp_datanpacked_data. For an INCR burst, the data is directly unpacked into unpacked_data For a WRAP burst, the data is unpacked such that unpacked_data[0] corresponds to the starting address. The assumption here is that data_to_unpack[] has a byte stream whose data starts from the address corresponding to the wrap boundary

data_to_unpack - The data to unpack.

unpacked_data - The unpacked data.

Member Attribute Documentation

rand int unsigned attribute
svt_atb_transaction::burst_length = 1

The variable represents the actual length of the burst. For eg. burst_length = 1 means a burst of length 1.

int attribute
svt_atb_transaction::current_data_beat_num = 0

This is a counter which is incremented for every dataword transfer specified as part of the burst. Useful when user would try to access the transaction class to know its current state. This represents the beat number for which the status is reflected in member xact_status.

bit attribute
svt_atb_transaction::current_flush_ready = 0

This attribute represents the value of afready signal for the current beat. This attribute is populated with the afready signal value at the end of each beat. User after getting the transaction object from the analysis port can identify if the data associated with current beat is flush data or not by checking the value of current_flush_valid and current_flush_ready attribute. If the value of current_flush_valid is 1 and current_flush_ready is 0 then only the data will be flush data. Applicable only when svt_atb_port_configuration :: flush_request_enable is set.

bit attribute
svt_atb_transaction::current_flush_valid = 0

This attribute represents the value of afvalid signal for the current beat. This attribute is populated with the afvalid signal value at the end of each beat. User after getting the transaction object from the analysis port can identify if the data associated with current beat is flush data or not by checking the value of current_flush_valid and current_flush_ready attribute. If the value of current_flush_valid is 1 and current_flush_ready is 0 then only the data will be flush data. Applicable only when svt_atb_port_configuration :: flush_request_enable is set.

rand bit [7:0] attribute
svt_atb_transaction::data_byte[]

Represents all the data bytes that will be placed onto databus as a data-word or byte(s). It is stored in byte-wise format and accessible as a collection of bytes. While placing these data bytes onto databus, Driver will align first byte i.e. data[0] to LSB of dataword.

parameter svt_atb_port_configuration :: data_width.

int attribute
svt_atb_transaction::data_ready_assertion_cycle[]

This variable stores the cycle information when data ready is asserted VIP updates the value of this variable, user does not need to program.

real attribute
svt_atb_transaction::data_ready_assertion_time[]

This variable stores the timestamp information when data valid is asserted VIP updates the value of this variable, user does not need to program.

rand int unsigned attribute
svt_atb_transaction::data_ready_delay[]

If configuration parameter svt_atb_port_configuration :: default_atready is FALSE, this member defines the ATREADY signal delay in number of clock cycles. The reference event for this delay is reference_event_for_data_ready_delay_enum

If configuration parameter svt_atb_port_configuration :: default_atready is TRUE, this member defines the number of clock cycles for which ATREADY signal should be deasserted after each handshake, before pulling it up again to its default value.

Applicable for ACTIVE SLAVE only.

int attribute
svt_atb_transaction::data_valid_assertion_cycle[]

This variable stores the cycle information when data valid is asserted VIP updates the value of this variable, user does not need to program.

real attribute
svt_atb_transaction::data_valid_assertion_time[]

This variable stores the timestamp information when data valid is asserted VIP updates the value of this variable, user does not need to program.

rand bit [SVT_ATB_MAX_DATA_VALID_BYTES_WIDTH-1:0] attribute
svt_atb_transaction::data_valid_bytes[]

Represents all the data valid bytes that will be placed onto databus to indicate how many data bytes from ATDATA bus should be captured. Data bytes that need to be captured should be counted from LSB bytes.

rand int unsigned attribute
svt_atb_transaction::data_valid_delay[]

Defines the delay in number of cycles for ATVALID signal. The reference event for this delay is:

For data_valid_delay[0] : reference_event_for_data_valid_delay
For remaining indices of data_valid_delay : reference_event_for_dat_valid_delay

Applicable for ACTIVE MASTER only.

int attribute
svt_atb_transaction::flush_ready_assertion_cycle

This variable stores the cycle information when flush ready is asserted VIP updates the value of this variable, user does not need to program.

real attribute
svt_atb_transaction::flush_ready_assertion_time

This variable stores the timestamp information when flush valid is asserted VIP updates the value of this variable, user does not need to program.

int attribute
svt_atb_transaction::flush_valid_assertion_cycle

This variable stores the cycle information when flush valid is asserted VIP updates the value of this variable, user does not need to program.

real attribute
svt_atb_transaction::flush_valid_assertion_time

This variable stores the timestamp information when flush valid is asserted VIP updates the value of this variable, user does not need to program.

rand bit [SVT_ATB_MAX_ID_WIDTH-1:0] attribute
svt_atb_transaction::id = 0

The variable holds the value of ATB Transaction ID associated with each transfer.
parameter svt_atb_port_configuration :: id_width.

int attribute
svt_atb_transaction::LONG_BURST_wt = 400

Weight used to control distribution of longer bursts within transaction generation.

This controls the distribution of the length of the bursts using burst_length field

int attribute
svt_atb_transaction::LONG_DELAY_wt = 1

Weight used to control distribution of long delays within transaction generation.

This controls the distribution of delays for the 'delay' fields (e.g., delays for asserting the ready signals).

int attribute
svt_atb_transaction::object_id = -1

Variable that holds the object_id of this transaction

string attribute
svt_atb_transaction::pa_object_type = ""

svt_atb_port_configuration attribute
svt_atb_transaction::port_cfg

The port configuration corresponding to this transaction

int attribute
svt_atb_transaction::port_id

Represents port ID. Not currently supported.

rand svt_atb_transaction :: reference_event_for_data_ready_delay_enum attribute
svt_atb_transaction::reference_event_data_ready_delay = PREV_DATA_VALID_ATR

Defines the reference events to delay ATREADY signal. Following are the different events under this category:

PREV_DATA_VALID: Reference event for ATREADY is assertion of the ATVALID signal

MANUAL_RREADY: (Not supported currently)

Currently only positive delay to assert ATREADY is supported.

rand svt_atb_transaction :: reference_event_for_data_valid_delay_enum attribute
svt_atb_transaction::reference_event_data_valid_delay = PREV_DATA_HANDSHAKE

Defines the reference events to delay ATVALID signal. Following are the different events under this category:

PREV_DATA_VALID: Reference event for ATVALID is assertion of previous ATVALID signal

PREV_DATA_HANDSHAKE: Reference event for ATVALID is completion of previous ATVALID/ATREADY handshake

For very first transaction in the simulation after reset, driver will use this delay to wait first before asserting first ATVALID. For first ATVALID of a particular transaction driver checks if the delay specified has already been elapsed from the mentioned reference point. If it is greater that or equal to specified delay then it will assert ATVALID immediately otherwise it will wait for rest of the delay before assertint ATVALID.

Currently only positive delay to assert ATVALID is supported.

int attribute
svt_atb_transaction::SHORT_BURST_wt = 500

Weight used to control distribution of short bursts within transaction generation.

This controls the distribution of the length of the bursts using burst_length field

int attribute
svt_atb_transaction::SHORT_DELAY_wt = 500

Weight used to control distribution of short delays within transaction generation.

This controls the distribution of delays for the 'delay' fields (e.g., delays for asserting the ready signals).

svt_atb_transaction :: status_enum attribute
svt_atb_transaction::xact_status = INITIAL

Represents the status of the ATB Transfer. Following are the possible status types:

INITIAL : VALID/READY has not been asserted
ACTIVE : At least one Data Transfer has Started
PARTIAL_ACCEPT : At least one Data Transfer has been completed
ACCEPT : All Data Transfer has been completed
FLUSH_ACK : Flush Acknowledgement has been asserted / Synchronization Info has been sent
ABORTED : Current transaction is aborted

rand svt_atb_transaction :: xact_type_enum attribute
svt_atb_transaction::xact_type = NORMAL_DATA

Represents the transaction type. Following are the possible transaction types:

NORMAL_DATA : Represent a transaction sending NORMAL Trace Data to Slave.
FLUSH_DATA : Represent a transaction sending FLUSHED Trace Data to Slave.
TRIGGER : Represent a transaction sending TRIGGER information to Slave.
SYNC_DATA : Represent a transaction sending SYNC information to Slave. This xact_type is only applicable to master transaction.

int attribute
svt_atb_transaction::ZERO_BURST_wt = 100

Weight used to control distribution of burst length to 1 within transaction generation.

This controls the distribution of the length of the bursts using burst_length field

int attribute
svt_atb_transaction::ZERO_DELAY_wt = 100

Weight used to control distribution of zero delay within transaction generation.

This controls the distribution of delays for the 'delay' fields (e.g., delays for asserting the ready signals).

VIP Smartsearch

svt_atb_transaction Class Reference

Detailed Description

Class Member Groupings

Public Member Functions

Public Attributes

Member Typedefs

Class Member Groupings

Group: Miscellaneous attributes

Group: ATB transaction status attributes

Group: ATB timing attributes

Group: ATB delay attributes

Group: ATB protocol attributes

Member Function Documentation

Member Attribute Documentation

Member Typedef Documentation

Class Member Groupings
Miscellaneous attributes	This group contains miscellaneous attributes which do not fall under any of the categories above.
ATB transaction status attributes	This group contains attributes which report the status of ATB transaction.
ATB timing attributes	This group contains attributes which are used to capture various timing details.
ATB delay attributes	This group contains attributes which can be used to control delays in ATB signals.
ATB protocol attributes	This group contains attributes which are relevant to ATB protocol.
Public Member Functions
function void	add_databeat ( bit [SVT_ATB_MAX_DATA_WIDTH-1:0] databeat )
function void	add_databeat_array ( bit [SVT_ATB_MAX_DATA_WIDTH-1:0] databeat[] )
function bit	decode_prop_val ( string prop_name, bit [1023:0] prop_val, ref string prop_val_string, input svt_pattern_data :: type_enum typ )
function svt_pattern	do_allocate_pattern ( )
function bit	do_compare ( ovm_object rhs, ovm_comparer comparer )
function void	do_copy ( ovm_object rhs )
function bit	do_is_valid ( bit silent = 1, int kind = RELEVANT )
function bit	encode_prop_val ( string prop_name, string prop_val_string, ref bit [1023:0] prop_val, input svt_pattern_data :: type_enum typ )
function int	get_burst_length ( )
function int	get_byte_count ( )
function bit [SVT_ATB_MAX_DATA_WIDTH-1:0]	get_databeat ( int curr_beat = -1 )
function string	get_mcd_class_name ( )
function svt_pa_object_data	get_pa_obj_data ( string uid = "", string typ = "", string parent_uid = "", string channel = "" )
function bit	get_prop_val ( string prop_name, ref bit [1023:0] prop_val, input int array_ix, ref svt_sequence_item_base data_obj )
function bit	is_trigger ( )
function void	new ( string name = "svt_atb_transaction", svt_atb_port_configuration port_cfg_handle = null )
function void	pack_data_to_byte_stream ( input bit [SVT_ATB_MAX_DATA_WIDTH-1:0] data_to_pack[], output bit [7:0] packed_data[] )
function string	psdisplay_short ( string prefix = "", bit hdr_only = 0 )
function int	reasonable_constraint_mode ( bit on_off )
function void	set_cfg ( svt_atb_port_configuration cfg )
function void	set_databeat ( int curr_beat = -1, bit [SVT_ATB_MAX_DATA_WIDTH-1:0] databeat )
function bit	set_prop_val ( string prop_name, bit [1023:0] prop_val, int array_ix )
function void	unpack_byte_stream_to_data ( input bit [7:0] data_to_unpack[], output bit [SVT_ATB_MAX_DATA_WIDTH-1:0] unpacked_data[] )
Public Attributes
rand int unsigned	burst_length = 1;
int	current_data_beat_num = 0;
bit	current_flush_ready = 0;
bit	current_flush_valid = 0;
rand bit [7:0]	data_byte []
int	data_ready_assertion_cycle []
real	data_ready_assertion_time []
rand int unsigned	data_ready_delay []
int	data_valid_assertion_cycle []
real	data_valid_assertion_time []
rand bit [SVT_ATB_MAX_DATA_VALID_BYTES_WIDTH-1:0]	data_valid_bytes []
rand int unsigned	data_valid_delay []
int	flush_ready_assertion_cycle
real	flush_ready_assertion_time
int	flush_valid_assertion_cycle
real	flush_valid_assertion_time
rand bit [SVT_ATB_MAX_ID_WIDTH-1:0]	id = 0;
int	LONG_BURST_wt = 400;
int	LONG_DELAY_wt = 1;
int	object_id = -1;
string	pa_object_type = "";
svt_atb_port_configuration	port_cfg
int	port_id
rand svt_atb_transaction :: reference_event_for_data_ready_delay_enum	reference_event_data_ready_delay
rand svt_atb_transaction :: reference_event_for_data_valid_delay_enum	reference_event_data_valid_delay
int	SHORT_BURST_wt = 500;
int	SHORT_DELAY_wt = 500;
svt_atb_transaction :: status_enum	xact_status
rand svt_atb_transaction :: xact_type_enum	xact_type
int	ZERO_BURST_wt = 100;
int	ZERO_DELAY_wt = 100;
Member Typedefs
typedef enum	reference_event_for_data_ready_delay_enum
typedef enum	reference_event_for_data_valid_delay_enum
typedef enum	status_enum
typedef enum	xact_type_enum
Class Member Groupings
Group: Miscellaneous attributes
This group contains miscellaneous attributes which do not fall under any of the categories above.

int	object_id = -1;
svt_atb_port_configuration	port_cfg
int	port_id
Group: ATB transaction status attributes
This group contains attributes which report the status of ATB transaction.

int	current_data_beat_num = 0;
bit	current_flush_ready = 0;
bit	current_flush_valid = 0;
svt_atb_transaction :: status_enum	xact_status
Group: ATB timing attributes
This group contains attributes which are used to capture various timing details.

int	data_ready_assertion_cycle []
real	data_ready_assertion_time []
int	data_valid_assertion_cycle []
real	data_valid_assertion_time []
int	flush_ready_assertion_cycle
real	flush_ready_assertion_time
int	flush_valid_assertion_cycle
real	flush_valid_assertion_time
Group: ATB delay attributes
This group contains attributes which can be used to control delays in ATB signals.

rand int unsigned	data_ready_delay []
rand int unsigned	data_valid_delay []
int	LONG_DELAY_wt = 1;
rand svt_atb_transaction :: reference_event_for_data_ready_delay_enum	reference_event_data_ready_delay
rand svt_atb_transaction :: reference_event_for_data_valid_delay_enum	reference_event_data_valid_delay
int	SHORT_DELAY_wt = 500;
int	ZERO_DELAY_wt = 100;
Group: ATB protocol attributes
This group contains attributes which are relevant to ATB protocol.

rand int unsigned	burst_length = 1;
rand bit [7:0]	data_byte []
rand bit [SVT_ATB_MAX_DATA_VALID_BYTES_WIDTH-1:0]	data_valid_bytes []
rand bit [SVT_ATB_MAX_ID_WIDTH-1:0]	id = 0;
int	LONG_BURST_wt = 400;
int	SHORT_BURST_wt = 500;
rand svt_atb_transaction :: xact_type_enum	xact_type
int	ZERO_BURST_wt = 100;