-- Copyright © 1993 by  McGraw-Hill, Inc. and Zainalabedin Navabi

-- FIGURE 9.38 




-- ENTITY DECLARATION OF PARWAN STATUS REGISTER UNIT :

LIBRARY cmos;
USE cmos.basic_utilities.ALL;
LIBRARY par_library;
USE par_library.par_utilities.ALL;
--
ENTITY status_register_unit IS
  PORT (in_flags : IN nibble; out_status : OUT nibble;  
        load, cm_carry, ck : IN qit );
END status_register_unit;
--


-- BEHAVIORAL DESCRIPTION OF PARWAN STATUS REGISTER UNIT :

ARCHITECTURE behavioral OF status_register_unit IS
BEGIN
  PROCESS (ck)
    VARIABLE internal_state : nibble := "0000";
    ALIAS internal_z : qit IS internal_state (1);
    ALIAS internal_c : qit IS internal_state (2);
  BEGIN
    IF (ck = '0') THEN
      IF (load = '1') THEN
        internal_state := in_flags;
      ELSIF (cm_carry = '1') THEN
        internal_c := NOT internal_c;
      END IF;
      out_status <= internal_state;
    END IF;
  END PROCESS;
END behavioral;
--