Attribute specification

attribute attribute_designator of entity_specification is expression ;

• entity_declarative_part
• architecture_declarative_part
• configuration_declarative_part
• package
• block_declarative_part
• function_declarative_part
• procedure_declarative_part
• process_declarative_part

attribute _simple_name

entity_name_list : entity_class

• relation { and relation }
• relation { or relation }
• relation { xor relation }
• relation [ nand relation ]
• relation [ nor relation ]
• relation { xnor relation }

Values for the attribute pin_number are determined. For the signal cin the attribute value is 10 and for the signal cout it is 5 .

ATTRIBUTE pin_number OF cin :
      SIGNAL IS 10 ;
 
ATTRIBUTE pin_number OF cout :
      SIGNAL IS 5 ;

For the label adder_1 the value of the attribute instance_location is (10,15) ; for all other labels it is (25,65) .

ATTRIBUTE instance_location OF
      adder_1 : LABEL IS ( 10, 15 ) ;
 
ATTRIBUTE instance_location OF
      OTHERS : LABEL IS ( 25, 65 ) ;

• The attribute author of the entity add_entity is seized by the string Martin .
• The attribute is_generic of the component cmos_nand is seized by the value false .
• The attribute creation_date of the architecture add_arc is seized by the Record (14,Aug,95) .
• The attribute safety of the procedure arithm_conv is seized by the value bug .
• The attribute confidentiality of the package cmos_pkg is seized by the value restrictive .

ATTRIBUTE author OF add_entity :
      ENTITY IS "Martin" ;
ATTRIBUTE is_generic OF cmos_nand :
      COMPONENT IS false ;
ATTRIBUTE creation_date OF add_arc :
      ARCHITECTURE IS (11, aug, 95) ;
ATTRIBUTE safety OF arithm_conv :
      PROCEDURE IS bug ;
ATTRIBUTE confidentiality OF    cmos_pkg : PACKAGE IS restrictive ;

By using predefined attributes the loop instruction can be written in a different way as well:

FOR i IN a1'LOW TO a1'HIGH
 
FOR i IN a1'RIGHT TO a1'LEFT
 
FOR i IN a1'REVERSE_RANGE
 
FOR i IN a1'RANGE

SIGNAL a1: bit_vector(3 DOWNTO 0) ;
...
PROCESS (a)
   BEGIN
   z<= "0000" :
   FOR i in 0 TO 3 LOOP
      IF (a = i) THEN
         z(i) <= '1' ;
      END IF ;
   END LOOP ;
END PROCESS ;
...