Ambiguous reference to type `UNSIGNED' - How to deal with this issue?

Discussion in 'VHDL' started by zhaoxiang.99@gmail.com, Jan 9, 2007.

  1. Guest

    I am using

    library IEEE;
    use IEEE.std_logic_1164.all;
    use IEEE.numeric_std.all;
    use IEEE.std_logic_arith.all;
    use IEEE.std_logic_textio.all;
    use std.textio.all;

    in a testbench, I need the CONV_STD_LOGIC function of std_logic_arith
    lib and the unsigned type of the numeric_std.all (the DUT has unsigned
    signal from this), but when compiling it in Aldec riviera, I met the"
    Ambiguous reference to type `UNSIGNED'" error. Could anybody can give
    me a clue?
     
    , Jan 9, 2007
    #1
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  2. writes:

    > I am using
    >
    > library IEEE;
    > use IEEE.std_logic_1164.all;
    > use IEEE.numeric_std.all;


    This line is good!

    > use IEEE.std_logic_arith.all;


    This line is bad. It is a non-standard library, which means your code
    can behave differently, depending on whos library you use to compile
    it with. And therefore you can have different simulation and
    synthesis results.

    > use IEEE.std_logic_textio.all;
    > use std.textio.all;
    >
    > in a testbench, I need the CONV_STD_LOGIC function of std_logic_arith
    > lib and the unsigned type of the numeric_std.all (the DUT has unsigned
    > signal from this), but when compiling it in Aldec riviera, I met the"
    > Ambiguous reference to type `UNSIGNED'" error. Could anybody can give
    > me a clue?


    The reason for the error you are getting is that UNSIGNED is defined
    in both libraries.

    Use just numeric_std and change the conv_unsigned to to_unsigned.

    See the VHDL FAQ for more gory details, and there's a number of
    threads from the past on this subject.

    <RANT>
    Why is it in this day and age when numeric_std has been around
    for so long that the vendors (and universties!) keep insisting on
    perpetuating std_logic_arith!?

    And having templates that include both std_logic_arith and
    std_logic_unsigned - sometimes when neither are required!
    </RANT>

    Sorry, had to get that off my chest!

    Cheers,

    Cheers,
    Martin

    --

    TRW Conekt - Consultancy in Engineering, Knowledge and Technology
    http://www.conekt.net/electronics.html
     
    Martin Thompson, Jan 9, 2007
    #2
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  3. On 09 Jan 2007 08:54:36 +0000, Martin Thompson
    <> wrote:

    ><RANT>

    [...]
    ></RANT>
    >
    >Sorry, had to get that off my chest!


    Welcome to LRA (Library Ranters Anonymous). We have
    regular meetings - approximately once a month - on this
    newsgroup when people post the offending use clauses.

    Sadly, the vendors who insist on providing
    use ieee.std_logic_arith.all;
    use ieee.std_logic_unsigned.all;
    in their default template aren't listening.
    --
    Jonathan Bromley, Consultant

    DOULOS - Developing Design Know-how
    VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

    Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK

    http://www.MYCOMPANY.com

    The contents of this message may contain personal views which
    are not the views of Doulos Ltd., unless specifically stated.
     
    Jonathan Bromley, Jan 9, 2007
    #3
  4. Jonathan Bromley <> writes:

    > On 09 Jan 2007 08:54:36 +0000, Martin Thompson
    > <> wrote:
    >
    > ><RANT>

    > [...]
    > ></RANT>
    > >
    > >Sorry, had to get that off my chest!

    >
    > Welcome to LRA (Library Ranters Anonymous).


    Although as our names are posted, would we be "ymous" instead :) ? Or
    "nonymous"... My Greek never was up to much.

    >We have regular meetings - approximately once a month - on this
    >newsgroup when people post the offending use clauses.


    Yes it happens rather a lot! I've been helping out a student at
    work whose tutor insists he does that sort of thing as well :-(

    Cheers,
    Martin

    --

    TRW Conekt - Consultancy in Engineering, Knowledge and Technology
    http://www.conekt.net/electronics.html
     
    Martin Thompson, Jan 10, 2007
    #4
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