Vhdl for Logic Synthesis, Third Edition

Appendix A

Package Listings

This Appendix lists the package headers of all the standard packages in the std and ieee libraries that are relevant to synthesis.

A.1 Package Standard

Package standard defines the basic types provided by VHDL in all circumstances. This is the VHDL-1993 version and is supplemented by package standard_additions (see Appendix A.2). In VHDL-2008, the additions are merged into package standard.

package standard is

  type boolean is (false, true);

  function "and"(l, r: boolean) return boolean;

  function "or"(l, r: boolean) return boolean;

  function "nand"(l, r: boolean) return boolean;

  function "nor"(l, r: boolean) return boolean;

  function "xor"(l, r: boolean) return boolean;

  function "xnor"(l, r: boolean) return boolean;

  function "not"(l: boolean) return boolean;

  function "="(l, r: boolean) return boolean;

  function "/="(l, r: boolean) return boolean;

  function "<"(l, r: boolean) return boolean;

  function "<="(l, r: boolean) return boolean;

  function ">"(l, r: boolean) return boolean;

  function ">="(l, r: boolean) return boolean;

  type bit is ('0', '1');

  function "and"(l, r: bit) return bit;

  function "or"(l, r: bit) return bit;

  function "nand"(l, r: bit) return bit;

  function "nor"(l, r: bit) return bit;

  function "xor"(l, r: bit) return bit;

  function "xnor"(l, r: bit) return bit;

  function "not"(l: bit) return bit;

  function "="(l, r: bit) return boolean;

  function "/="(l, r: bit) return boolean;

  function "<"(l, r: bit) ...