Generic Records (attempted via vhdl 2008 generic package)

问题

I want to write a library for component C, the component is split internally into two supcomponents c1 and c2, which are configurable by generics. The submodules should be connected by a record, that depends on the generics. The record should also be used within the components. Usually I would instantiate the record in a package, and use the package in the files for the subcomponents and in the file for the component. Since it is generic I figured using a generic Package (VHDL-2008) might offer a solution.

The Problem is I need to access the record also from within the subcomponents. To do so I need to use thePackage, however to use a generic package I need to pass initial values (as far as I know).

So I tried (note: Iam not working with records here, I am just trying to get access to a generic package from a generic component, where I parameterize(?) the package with the parameters of the component):

entity genericPackagePart is
    generic(
        outputValue : integer
    );
    port(
        result: out integer
    );
end entity;

architecture behav of genericPackagePart is
    package test is new work.genericPackage
    generic map(
        genSize => outputValue
    );

    use work.test.all;
begin
    result <= dummy;  -- dummy is a constant from genericPackage set to the value genSize (generic parameter)
end architecture;

However I get the following errors from modelsim:

** Error: (vcom-11) Could not find work.test.
** Error: genericPackagePart.vhd(17): (vcom-1195) Cannot find expanded name "work.test".
** Error: genericPackagePart.vhd(17): Unknown expanded name.
** Error: genericPackagePart.vhd(19): (vcom-1136) Unknown identifier "dummy".
** Error: genericPackagePart.vhd(20): VHDL Compiler exiting

Update: I tried wrapping the genericPackagePart in a generic package and to instantiate the genericPackage from within that package with the generics, this did not work either.

The flow would have been:

Testbench => Instantiate genericPackagePart and genericPackage with generic parameters
The record is available in the testbench from genericPackage
Inside genericPackagePart genericPackage is instantiated with the parameters passed to genericPackagePart
the record is available inside genericPackagePart

Modelsim gave Errors (test is the name I gave to the parameterizes instance of genericPackage in genericPackagePart, this is from the compile of genericPackagePart):

** Error: (vcom-11) Could not find work.test.
** Error: genericPackagePart.vhd(11): (vcom-1195) Cannot find expanded name "work.test".
** Error: genericPackagePart.vhd(11): Unknown expanded name.
** Error: genericPackagePart.vhd(13): near "entity": expecting END

I looked at Passing Generics to Record Port Types but that does not solve the issue of the package instantiation based on generics

For completness here is the package and a testbench:

Package:

package genericPackage is
    generic(genSize : integer := 1);

    constant dummy : integer := genSize;
end package;

Testbench:

package myGenericPackage is new work.genericPackage
generic map(
    genSize => 5
);

use work.myGenericPackage.all;

entity genericPackageTestbench is
end entity;

architecture testbench of genericPackageTestbench is
    signal testsignal : integer;
    signal testsignal2 : integer;
    signal dummy : integer := 12;

    component genericPackagePart is
    generic(
        outputValue : integer
    );
    port(
        result: out integer
    );
    end component;
begin
    test : process is
    begin
        wait for 20 ns;
        testsignal <= dummy;
        wait for 20 ns;
        testsignal <= work.myGenericPackage.dummy;
        wait;
    end process;

    testPart: genericPackagePart
        port map(result => testsignal2)
        generic map(outputValue => 128);
end architecture;

回答1:

I think the problem was that your package test needs to be defined in the entity area, not the architecture area:

package genericPackage is
    generic(genSize : integer := 1);
    constant dummy : integer := genSize;
end package;
entity genericPackagePart is
    generic(outputValue : integer);
    port(result : out integer);

    -- *** Generic package instantiated here ***
    package test is new work.genericPackage
       generic map(genSize => outputValue);

end entity;
architecture behav of genericPackagePart is
    use test.all;
begin
    result <= dummy;  -- dummy is from genericPackage (=genSize)
end architecture;

Here's how I tested it (based on your testbench):

package myGenericPackage is new work.genericPackage
   generic map(genSize => 5);

use work.myGenericPackage.all;

entity genericPackageTestbench is
end entity;

architecture testbench of genericPackageTestbench is
    signal testsignal  : integer;
    signal testsignal2 : integer;
begin
    test : process is
    begin
        testsignal <= work.myGenericPackage.dummy;
        wait for 20 ns;

        assert testsignal = work.myGenericPackage.dummy 
            report "test signal should be work.myGenericPackage.dummy" 
            severity error;
        assert testsignal2 = 128 report "testsignal2 /= 128" severity error;
        report "testsignal = " & integer'image(testsignal);
        report "testsignal2 = " & integer'image(testsignal2);
        report "Finished";
        wait;
    end process;

    testPart : entity work.genericPackagePart
        generic map(outputValue => 128)
        port map(result         => testsignal2);
end architecture;

Compiled and simulated with Modelsim 10.2:

vcom -2008 genpacktest.vhd; vsim -c genericPackageTestbench -do "run -all; quit"

Which reports:

# Loading std.standard
# Loading work.genericpackage
# Loading work.mygenericpackage
# Loading work.genericpackagetestbench(testbench)
# Loading work.genericpackagepart(behav)
# run -all 
# ** Note: Finished
#    Time: 20 ns  Iteration: 0  Instance: /genericpackagetestbench
# ** Note: testsignal = 5
#    Time: 20 ns  Iteration: 0  Instance: /genericpackagetestbench
# ** Note: testsignal2 = 128
#    Time: 20 ns  Iteration: 0  Instance: /genericpackagetestbench
#  quit

来源：https://stackoverflow.com/questions/16056291/generic-records-attempted-via-vhdl-2008-generic-package

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