svt_8b10b_data Class Reference

Inheritance diagram for class svt_8b10b_data:

List of all members.

Detailed Description

A utility class that encapsulates an individual unit of transfer in an 8b/10b encoding protocol. The object can be initialized with either eight bit data or ten bit data. Methods are present on the object to encode eight bit data into its ten bit representation, or decode ten bit data into its eight bit representation. The current running disparity must be provided to encode or decode the data properly, and the updated running disparity value is returned from these functions via a ref argument.

The 8b/10b and 10b/8b conversion methods utilize lookup tables instead of calculations for performance reasons. The data values represent the full 8-bit state space, but the K-code values only utilize a subset of the 8-bit state space. Therefore, the following K-code values are incorporated into the lookup tables:


Public Member Functions

function bit  decode_data ( bit [9:0] value, ref bit RD )
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 bit  do_is_valid ( bit silent = 1, int kind = -1 )
function bit  encode_data ( bit [7:0] value, ref bit RD )
function bit  encode_kcode ( bit [7:0] value, ref bit RD )
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 string  get_code_group ( )
function string  get_mcd_class_name ( )
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_valid_10b ( bit [9:0] value, logic disp_in = 1'bx )
function bit  is_valid_K8b ( bit [7:0] value, logic disp_in = 1'bx )
function bit [8:0]   lookup_8b ( bit [9:0] value, bit disp_in )
function bit [9:0]   lookup_D10b ( bit [7:0] value, bit disp_in )
function bit [9:0]   lookup_K10b ( bit [7:0] value, bit disp_in )
function void  new ( string name = "svt_8b10b_data", string suite_name = "" )
function string  psdisplay_meta_info ( string prefix = "" )
function string  psdisplay_short ( string prefix = "", bit hdr_only = 0 )
function int  reasonable_constraint_mode ( bit on_off )
function bit  set_prop_val ( string prop_name, bit [1023:0] prop_val, int array_ix )

Public Attributes

rand bit [9:0]   data_10bit 
rand bit [7:0]   data_8bit 
rand bit  data_k 
svt_sequence_item :: status_enum  status 

Protected Attributes

static protected bit [8:0]   lookup_table_8b [int] 
static protected bit [9:0]   lookup_table_D10b [512] 
static protected integer  lookup_table_disparity [int] 
static protected bit [9:0]   lookup_table_K10b [int] 

Constraints

constraint  reasonable_data_10bit  ( )
constraint  reasonable_data_8bit  ( )

Member Function Documentation

  function bit
 svt_8b10b_data::decode_data
 (  bit [9:0] value , ref bit RD  ) 

Decodes a ten bit data value into its eight bit representation. The data_8bit, data_k, and data_10bit values are updated as a result of calling this function. The function returns 0 and no properties are updated if Xs or Zs are passed in via the arguments, or if the value that is passed in is not in the 10b/8b lookup table.

value - Ten bit value to be decoded

RD - The value provided to this argument determines whether the ten bit value is selected from the positive or negative disparity column. The value is updated with the disparity of the new ten bit value that is selected. If the encode operation fails then the value remains unchanged.

  function bit
 svt_8b10b_data::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. If provided the type is used by the default implementation to choose an appropriate conversion method. If the type is specified as UNDEF then the the field is assumed to be an int field and the string is assumed to be an ascii int representation. Derived classes can extend this method to support other field representations such as strings, enums, bitvecs, etc.

prop_name - The name of the property being decoded.

prop_val - The bit vector decoding of prop_val_string.

prop_val_string - The resulting decoded value.

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

Return values - Status indicating the success/failure of the decode.

 Superseded functions 
 svt_sequence_item_base :: decode_prop_val 
 svt_sequence_item :: decode_prop_val 

  function svt_pattern
 svt_8b10b_data::do_allocate_pattern
 (   ) 

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

  function bit
 svt_8b10b_data::do_compare
 (  ovm_object rhs , ovm_comparer comparer  ) 

Override the 'do_compare' method to compare fields directly.
 Superseded functions 
 ovm_object :: do_compare 
 svt_sequence_item_base :: do_compare 
 svt_sequence_item :: do_compare 

  function bit
 svt_8b10b_data::do_is_valid
 (  bit silent = 1, int kind = -1  ) 

Checks to see that the data field values are valid, focusing mainly on checking/enforcing valid_ranges constraint. Only supported kind values are -1 and svt_sequence_item_base :: COMPLETE. If protocol defines physical representation for transaction then -1 does RELEVANT is_valid. If not, -1 does COMPLETE (i.e., all fields checked) is_valid. svt_sequence_item_base :: COMPLETE always results in COMPLETE is_valid.
 Superseded functions 
 svt_sequence_item_base :: do_is_valid 
 svt_sequence_item :: do_is_valid 

  function bit
 svt_8b10b_data::encode_data
 (  bit [7:0] value , ref bit RD  ) 

Encodes an eight bit data value into its ten bit representation. The data_8bit, data_k, and data_10bit values are updated as a result of calling this function. The function returns 0 and no properties are updated if Xs or Zs are passed in via the arguments.

value - Eight bit value to be encoded

RD - The value provided to this argument determines whether the ten bit value is selected from the positive or negative disparity column. The value is updated with the disparity of the new ten bit value that is selected. If the encode operation fails then the value remains unchanged. value

  function bit
 svt_8b10b_data::encode_kcode
 (  bit [7:0] value , ref bit RD  ) 

Encodes an eight bit control value into its ten bit representation. The data_8bit, data_k, and data_10bit values are updated as a result of calling this function. The function returns 0 and no properties are updated if Xs or Zs are passed in via the arguments, or if the value passed in is not in the 8b/10b lookup table.

value - Eight bit value to be encoded

RD - The value provided to this argument determines whether the ten bit value is selected from the positive or negative disparity column. The value is updated with the disparity of the new ten bit value that is selected. If the encode operation fails then the value remains unchanged.

  function bit
 svt_8b10b_data::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. If provided the type is used by the default implementation to choose an appropriate conversion method. If the type is specified as UNDEF then the the field is assumed to be an int field and the string is assumed to be an ascii int representation. Derived classes can extend this method to support other field representations such as strings, enums, bitvecs, etc.

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 - Status indicating the success/failure of the encode.

 Superseded functions 
 svt_sequence_item_base :: encode_prop_val 
 svt_sequence_item :: encode_prop_val 

  function string
 svt_8b10b_data::get_code_group
 (   ) 

Returns the code group of the data value as a string

  function string
 svt_8b10b_data::get_mcd_class_name
 (   ) 

Returns the class name for the object.
 Superseded functions 
 svt_sequence_item_base :: get_mcd_class_name 

  function bit
 svt_8b10b_data::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 

  function bit
 svt_8b10b_data::is_valid_10b
 (  bit [9:0] value , logic disp_in = 1'bx  ) 

Returns true if the provided value is in the 10 bit lookup table. Otherwise returns false.

value - Value to be tested

disp_in - Optional disparity to test against. If this value is not provided, then the function returns true whether the value was found in the positive or negative disparity column.

  function bit
 svt_8b10b_data::is_valid_K8b
 (  bit [7:0] value , logic disp_in = 1'bx  ) 

Returns true if the provided value is in the 8 bit control character lookup table. Otherwise returns false.

value - Value to be tested

disp_in - Optional disparity to test against. If this value is not provided, then the function returns true whether the value was found in the positive or negative disparity column.

  function bit [8:0]
 svt_8b10b_data::lookup_8b
 (  bit [9:0] value , bit disp_in  ) 

Access to the 10b lookup tables without disparity calculations. These are added to make expressing constraints possible when VCS supports this feature.

value - Value to be applied to the lookup table

disp_in - Disparity column that the 8 bit value will be returned from

  function bit [9:0]
 svt_8b10b_data::lookup_D10b
 (  bit [7:0] value , bit disp_in  ) 

Access to the D8b lookup tables without disparity calculations. These are added to make expressing constraints possible when VCS supports this feature.

value - Value to be applied to the lookup table

disp_in - Disparity column that the 10 bit value will be returned from

  function bit [9:0]
 svt_8b10b_data::lookup_K10b
 (  bit [7:0] value , bit disp_in  ) 

Access to the K8b lookup tables without disparity calculations. These are added to make expressing constraints possible when VCS supports this feature.

value - Value to be applied to the lookup table

disp_in - Disparity column that the 10 bit value will be returned from

  function void
 svt_8b10b_data::new
 (  string name = "svt_8b10b_data", string suite_name = ""  ) 

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

name - Instance name of the transaction

suite_name - A String that identifies the product suite to which the transaction object belongs.

 Superseded functions 
 svt_sequence_item_base :: new 
 svt_sequence_item :: new 

  function string
 svt_8b10b_data::psdisplay_meta_info
 (  string prefix = ""  ) 

Displays the meta information to a string. Each line of the generated output is preceded by prefix. Extends class flexibility in choosing what meta information should be displayed.
 Superseded functions 
 svt_sequence_item :: psdisplay_meta_info 

  function string
 svt_8b10b_data::psdisplay_short
 (  string prefix = "", bit hdr_only = 0  ) 

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

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 transaction 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 

  function int
 svt_8b10b_data::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 

  function bit
 svt_8b10b_data::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 

Member Attribute Documentation

 rand bit [9:0]   attribute
 svt_8b10b_data::data_10bit

Ten bit representation of the data

This property is declared rand, but the rand_mode is disabled in the constructor.

 rand bit [7:0]   attribute
 svt_8b10b_data::data_8bit

Eight bit representation of the data

This property is declared rand, but the rand_mode is disabled in the constructor.

 rand bit  attribute
 svt_8b10b_data::data_k

Flag that determines when the eight bit data represents a control character

This property is declared rand, but the rand_mode is disabled in the constructor.

 static protected bit [8:0]   attribute
 svt_8b10b_data::lookup_table_8b[int]

Ten bit value to eight bit lookup table

 static protected bit [9:0]   attribute
 svt_8b10b_data::lookup_table_D10b[512]

Eight bit data value to ten bit lookup table

 static protected integer  attribute
 svt_8b10b_data::lookup_table_disparity[int]

Disparity lookup table (indexed by ten bit values)

 static protected bit [9:0]   attribute
 svt_8b10b_data::lookup_table_K10b[int]

Eight bit control value to ten bit lookup table

 svt_sequence_item :: status_enum  attribute
 svt_8b10b_data::status = INITIAL

Status information about the current processing state

Member Constraint Documentation

  constraint
 svt_8b10b_data::reasonable_data_10bit

Ensures that the 10 bit representation matches the 8 bit representation with either positive or negative disparity

Note: Functions in constraints won't be supported until VCS 2008.03, so this constraint is commented out for now.

constraint reasonable_data_10bit {
    /*
    if (data_k == 1'b0) {
      data_10bit inside { lookup_D10b(data_8bit, 1'b0), lookup_D10b(data_8bit, 1'b1) };
    }
    else {
      data_10bit inside { lookup_K10b(data_8bit, 1'b0), lookup_K10b(data_8bit, 1'b1) };
    }
    */
  }

  constraint
 svt_8b10b_data::reasonable_data_8bit

Ensures that the 8 bit representation matches the 10 bit representation and if the data represents a control character, then the constraint ensures that a valid control character is selected

Note: Functions in constraints won't be supported until VCS 2008.03, so this constraint is commented out for now.

constraint reasonable_data_8bit {
    /*
    {data_k, data_8bit} inside { lookup_8b(data_10bit, 1'b0), lookup_8b(data_10bit, 1'b1) };
     if (data_k == 1'b1) {
      lookup_table_K10b.exists(data_8bit);
    }
    */
  }

08 August 2024, Copyright © 2024 Synopsys, Inc.