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 Need some more information about Trimmed index [CDFG-420] 

Last post Fri, Mar 30 2007 10:53 AM by archive. 2 replies.
Started by archive 30 Mar 2007 10:53 AM. Topic has 2 replies and 1293 views
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  • Fri, Mar 30 2007 10:53 AM

    • archive
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    Need some more information about Trimmed index [CDFG-420] Reply

    While using RTL compiler I get the following warning message. [CDFG-420]

    Trimmed index 'portIn' of signal 'startT0' from 2 bits to 1 bits in file

    The code for above is :

    parameter PORTS = 4;
    input wire [1:0]    portIn;
    input wire [3:0]    cntIn;
    reg [PORTS -1:0]        pauseDa;

    case (cntIn)
                0: pauseDa[portIn] <=  x;

    I noticed that in other instances, when I used an integer instead of a binary number, it gave the same warning.
    As soon as I converted 0 to 1'b0 and 1 to 1'b1, this warning was not issued any more.

    In the above case, whenever, a bus was used as the index, it issues the above warning.  From the code above, we
    know pauseDa can have 4 values and portIn can address 4 locations.  But the warning says trimming index to 1 bit.

    There was no such problem when integers were used for indexing.  (in a for loop).  So, I modified the code as follows,

    int portIn_int;
                                                                                               
    assign portIn_int = portIn;

            case (cntIn)
                0: pauseDa[portIn_int] <= x;

    But I continue to get the same warning. 

    Trimmed index 'portIn_int' of signal 'pauseDa' from 32 bits to 2 bits

    The problem is even though the RTL and netlist can be verified each time using verplex, I have to still go through the
    logs to make sure that all these warnings are ok.

    Alternatively, I could set:

    set_attr hdl_trim_target_index false

    but it mentions that the design is not optimized.  I did verify, that there is a slight increase in area with the above
    setting to false.  Default is true. 

    Any suggestions or similar experiances are appreciated.

    Thanks,
    Amar.


     


    Originally posted in cdnusers.org by adudyala
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  • Fri, Mar 30 2007 10:56 AM

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    RE: Need some more information about Trimmed index [CDFG-420] Reply

    Sorry,

    I put the wrong Warning number. The correct one is : [CDFG2G-617]

    Thanks,
    Amar


    Originally posted in cdnusers.org by adudyala
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  • Fri, Mar 30 2007 4:36 PM

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    RE: Need some more information about Trimmed index [CDFG-420] Reply

    Hi Amar, just tried the following code: module debug ( input wire [1:0] portIn, input wire [3:0] cntIn, in1, output wire [3:0] out1 ); parameter PORTS = 4; reg [PORTS -1:0] pauseDa; // wire integer portIn_int; // assign portIn_int = portIn; always @(cntIn or portIn or in1) begin case (cntIn) 0: pauseDa[portIn] <= in1; endcase // case(cntIn) end // always @ (cntIn) assign out1 = pauseDa; endmodule // debug and I can see the CDFG2G-617 when I do the mod you did. In that case, it makes sense to me since integers are 32 bits and pauseDa is 2 hence the tool has to trim or else you could give up some optimizations. I noticed that your thread talks about another signal for which you do not show the code > Trimmed index 'portIn' of signal 'startT0' from 2 bits to 1 bits in file It probably is a similar issue. If you can share the code with startT0 I can probably help you out. I am using 6.2-s010, what version are you using ? take care, gh-


    Originally posted in cdnusers.org by grasshopper
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Started by archive at 30 Mar 2007 10:53 AM. Topic has 2 replies.