实体声明定义了设计实体与外部的接口 结构: ENTITY identifier IS entity header (generic and/or port clauses) entity declarative part (declarations for subprograms types signa BEGIN entity statement part END identifier实体声明定义了设计实体与外部的接口 结构： ENTITY identifier IS entity_header --(generic and/or port clauses) entity_declarative_part --(declarations for subprograms, -- types, signals, ……) BEGIN entity_statement_part END identifier ;