Re: using typedef intput argument for function

Altera_Forum · ‎09-13-2017

Hi

I want to pass a signal with a defined typedef into a function, however I got this error:

10476: type identifier "data" does nto agree with its usage as "int_array" type.

10559: actual formal parameter "data" must be a signal

and I couldn't find an answer for it. My code is as followed.


-------------- Sub function ---------------------
package function_list is
    --* typedef 
    type    int_array    is    array    (integer range <>) of integer;
    
    --* functions
    function sum(signal data: int_array(0 to 9)) return integer;
end function_list;
package body function_list is
    function sum(signal data: int_array(0 to 9)) return integer is
        variable sum_val:    integer range 0 to 255    :=0;
    begin
        for i in 0 to 9 loop
            sum_val:= sum_val + data(i);
        end loop;
        return sum_val;
    end sum;
end function_list;
--------------- Main file --------
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;
use work.function_list.all;
architecture rtl of main is
    type    int_array    is    array    (integer range <>) of integer;
    signal    data:    int_array(0 to 9);
begin
    sum_process: process(sum_flag,clk)
        variable sum_val: integer range 0 to 255;
    begin
        if rising_edge(clk) then
            if sum_flag = '1' then 
                sum_val:= sum(data); 
            end if;
        end if;
    end process;    
end rtl;

Altera_Forum · ‎09-13-2017

This is because of the strong typing in VHDL.

The int_array type in the function_list package is not the same type as the one you declared in the "main" entity.

Hence the missmatch when you call the sum function, as data is int_array, while the function wants work.function_list.int_array

The fix here is to remove the type declaration from the main file. You dont need it as it is already declared in the included function_list package.

note: VHDL 2008 includes the integer_vector type that is an array of integers.

Altera_Forum · ‎09-14-2017

Thanks Tricky.

It get it now. Just one more question regarding to "integer_vector":

- How to use / which package do I have to include so that I can use this "integer_vector" type ? Since it gives no suggestion for this type when I'm typing. I tried to search for answer but couldn't find.

Thanks

Altera_Forum · ‎09-14-2017

First of all, integer_vector requires that you use VHDL 2008. Quartus does not have full 2008 support unless you use Quartus Pro 17+, so it may not be supported.

integer_vector is part of the std.standard package that is included in all VHDL files by default, so no package inclusion is necessary.