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Record types

Record types, like array types, are composite types because they represent a collection of values. In the case of a record type, the collection of values is organized by name and can be of different types. Each value in the collection has a name and is referenced by that name. A record type is declared by listing the named values and their types. The grammar rule for the record type definition is:

element-declaration : name-list ":" subtype ";"
record-type-definition : 
    RECORD element-declaration 
      { element-declaration } 
    END RECORD

There are no predefined record types. The following is an example of a record type that might be used to define a cache element

type cache_element is record
    tag : integer range 0 to 256;
    valid : boolean;
    writeback : boolean;
    data : bit_vector (15 downto 0);
  end record;

If x was a data object of the cache_element type then the value of the valid field of that data object is referenced by x.valid using the dot notation.