如何将数组类型作为通用类型参数传递给VHDL包? [英] How to pass an array type as generic type parameter to a VHDL package?

问题描述

我正在处理VHDL-2008中的通用包(列表).该程序包具有元素类型的通用类型.如果我在包中声明了此元素类型的数组类型，则它是一种新类型.所以例如整数，我的新integer_array将与库ieee中的integer_vector不兼容.

I'm working on a generic package (list) in VHDL-2008. This package has a type generic for the element type. If I declare an array type of this element type within the package, it's a new type. So for e.g. integer, my new integer_array would be incompatible with integer_vector from library ieee.

所以我还需要传入数组类型(例如integer_vector).当该数组类型的数组实例与'range 属性一起使用时，它会在QuestaSim中向我发出警告:

So I need also to pass in the array type (e.g. integer_vector). When an array instance of that array type is used with a 'range attribute, it gives me a warning in QuestaSim:

属性范围"的前缀必须适合于数组对象或必须表示数组子类型.

Prefix of attribute "range" must be appropriate for an array object or must denote an array subtype.

如何表示泛型类型参数是数组?

How do a denote that a generic type parameter is an array?

通用软件包:

package SortListGenericPkg is
  generic (
    type ElementType;  -- e.g. integer
    type ArrayofElementType;  -- e.g. integer_vector
    function LessThan(L : ElementType; R : ElementType) return boolean;     -- e.g. "<"
    function LessEqual(L : ElementType; R : ElementType) return boolean     -- e.g. "<="
  );

  function inside (constant E : ElementType; constant A : in ArrayofElementType) return boolean;
end package;

package body SortListGenericPkg is
  function inside (constant E : ElementType; constant A : in ArrayofElementType) return boolean is
  begin
    for i in A'range loop  -- this line causes the error
      if E = A(i) then
        return TRUE ;
      end if ;
    end loop ;
    return FALSE ;
  end function inside ;
end package body;

实例:

package SortListPkg is
  package SortListPkg_int is new work.SortListGenericPkg
    generic map (
      ElementType        => integer,
      ArrayofElementType => integer_vector,
      LessThan           => "<",
      LessEqual          => "<="
    );
  alias Integer_SortList is SortListPkg_int.SortListPType;
end package SortListPkg ;

推荐答案

ModelSim会产生类似的错误/警告，因此可能是VHDL标准问题.

ModelSim makes a similar error/warning, so it's maybe a VHDL standard issues.

一种解决方法是将 ArrayofElementType 声明为包的一部分，例如:

A workaround is to declare ArrayofElementType as part of the package, like:

package SortListGenericPkg is
  generic (
    type ElementType  -- e.g. integer
  );
  type ArrayofElementType is array (integer range <>) of ElementType;
  function inside(constant E : ElementType; constant A : in ArrayofElementType) return boolean;
end package;

，然后在调用 inside 时转换参数，例如:

and then convert the argument when inside is called, like:

... inside(int, ArrayofElementType(int_vec));

或在可能/可行时声明参数时，简单地使用 ArrayofElementType 作为类型.

or simple use ArrayofElementType as type when declaring the argument if possible/feasible.

这篇关于如何将数组类型作为通用类型参数传递给VHDL包?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！