VHDL-2005 package changes

Discussion in 'VHDL' started by David Bishop, Nov 19, 2004.

  1. David Bishop

    David Bishop Guest

    In the next update to VHDL we are planning several changes and
    additions to the standard packages.

    For the current packages, std_logic_1164, numeric_std, and
    numeric_bit we plan to include the "read" and "write"
    procedures in the package. This will also be done for any
    new packages of types introduced in this revision.
    Note, read and write procedures for standard types (bit,
    bit_vector, integer, ...) will still be located in std.textio.

    Std_logic_textio has been donated to the IEEE. All the read
    and write functions that are proposed for std_logic_1164 are
    intended to be backward compatible with this std_logic_textio.
    As a result, we will be including a blank std_logic_textio
    so that references to std_logic_textio will not cause issues.

    It also means that if you have defined your own read and write
    procedures for the types in std_logic_1164, numeric_std, or
    numeric_bit that you will need to comment these procedures out
    in the packages in which you have defined them.

    Is this an issue for you and if so how big? Are you willing
    to trade the modifications to your packages in exchange for
    what we feel is a better package architecture for the future?

    Alternately would it be better to keep the read and write for
    std_logic_1164, numeric_std, and numeric_bit in separate packages
    such as std_logic_textio, numeric_std_textio, and numeric_bit_textio?
    Our concern with this approach for printing is that you need
    twice the number of packages for printing. Consider that we
    are also introducing packages for fixed point and floating
    point in this revision and that they would need to be done
    in a manner consistent with numeric_std and std_logic_1164.


    For details of the change proposal see:
    http://www.eda.org/vhdl-200x/vhdl-200x-ft

    For proposed revisions to the package (and to try them out) see:
    http://www.eda.org/vhdl-200x/vhdl-200x-ft/packages/files.html
    Note any debug help with the new packages would be appreciated.
     
    David Bishop, Nov 19, 2004
    #1
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  2. David Bishop wrote:

    > It also means that if you have defined your own read and write
    > procedures for the types in std_logic_1164, numeric_std, or
    > numeric_bit that you will need to comment these procedures out
    > in the packages in which you have defined them.
    >
    > Is this an issue for you and if so how big?


    Not an issue. I use very little file io, and
    when I do, I use the non-overloaded read/write.
    Even if I had written my own read/write procedures,
    it wouldn't be much trouble to rename them.

    > Are you willing
    > to trade the modifications to your packages in exchange for
    > what we feel is a better package architecture for the future?


    Yes. As long as I can use numeric_std and the
    base vhdl read/write at the same time.

    > Alternately would it be better to keep the read and write for
    > std_logic_1164, numeric_std, and numeric_bit in separate packages
    > such as std_logic_textio, numeric_std_textio, and numeric_bit_textio?
    > Our concern with this approach for printing is that you need
    > twice the number of packages for printing.


    I think you got it right. Build in as much as you can.

    Thanks to you and everyone working on new vhdl standards.

    -- Mike Treseler
     
    Mike Treseler, Nov 20, 2004
    #2
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  3. On Fri, 19 Nov 2004 10:40:52 -0500, David Bishop <>
    wrote:

    >Std_logic_textio has been donated to the IEEE.


    Does that mean they're going to own the copyright and not allow the
    source to be distributed for free? That would be a bad thing.

    Regards,
    Allan
     
    Allan Herriman, Nov 22, 2004
    #3
  4. David Bishop

    David Bishop Guest

    Allan Herriman wrote:
    > On Fri, 19 Nov 2004 10:40:52 -0500, David Bishop <>
    > wrote:
    >
    >
    >>Std_logic_textio has been donated to the IEEE.

    >
    > Does that mean they're going to own the copyright and not allow the
    > source to be distributed for free? That would be a bad thing.


    One of the objectives of the vhdl-200x-ft group is to allow us
    to freely distribute the source code for these packages. The fact
    that the IEEE puts it's copyright on the code that I've worked on
    has been a thorn in my side for years now.

    Rest assured, we are working on this issue.
     
    David Bishop, Nov 22, 2004
    #4
  5. David Bishop

    Jim Lewis Guest

    Allan,
    I share that concern also. The previous problem
    with IEEE was that the packages were a large part
    of the standard. Since the pacakges are now
    going to be part of 1076, we may be able to
    overcome this issue.

    On the other hand, while it would be nice to have
    source, it is not necessary. What we really need
    is good man page type documentation about each of
    the functions in the packages.

    Cheers,
    Jim




    > On Fri, 19 Nov 2004 10:40:52 -0500, David Bishop <>
    > wrote:
    >
    >
    >>Std_logic_textio has been donated to the IEEE.

    >
    >
    > Does that mean they're going to own the copyright and not allow the
    > source to be distributed for free? That would be a bad thing.
    >
    > Regards,
    > Allan



    --
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Jim Lewis
    Director of Training mailto:
    SynthWorks Design Inc. http://www.SynthWorks.com
    1-503-590-4787

    Expert VHDL Training for Hardware Design and Verification
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     
    Jim Lewis, Nov 22, 2004
    #5
  6. On Sun, 21 Nov 2004 20:49:33 -0800, Jim Lewis <>
    wrote:

    >Allan,
    >I share that concern also. The previous problem
    >with IEEE was that the packages were a large part
    >of the standard. Since the pacakges are now
    >going to be part of 1076, we may be able to
    >overcome this issue.
    >
    >On the other hand, while it would be nice to have
    >source, it is not necessary. What we really need
    >is good man page type documentation about each of
    >the functions in the packages.


    VHDL has separate package and package body. Users should really only
    need the package.
    For some of the existing IEEE packages though, you need the package
    body just to work out what the functions actually do. Surely a little
    comment in the package wouldn't be too hard?

    Regards,
    Allan
     
    Allan Herriman, Nov 22, 2004
    #6
  7. David Bishop

    Jim Lewis Guest

    Allan,
    > VHDL has separate package and package body. Users should really only
    > need the package.
    > For some of the existing IEEE packages though, you need the package
    > body just to work out what the functions actually do. Surely a little
    > comment in the package wouldn't be too hard?


    If I am going to write user documentation, I would rather
    keep it separate and make it public domain - that way
    IEEE can't claim it and keep it for themselves.

    Regards,
    Jim

    --
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Jim Lewis
    Director of Training mailto:
    SynthWorks Design Inc. http://www.SynthWorks.com
    1-503-590-4787

    Expert VHDL Training for Hardware Design and Verification
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     
    Jim Lewis, Nov 22, 2004
    #7
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