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  3. How to force RTL compiler to use a particular net name

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How to force RTL compiler to use a particular net name

deeps4
deeps4 over 13 years ago

 Hi,

I have a RTL which after synthesis looks as in  the snippet  mentioned below..

 ===================================

wire [2:0] seed_inp;
 wire [2:0] seed_outp;

output[2:0] seed_outp;

  wire scan_5_q, scan_9_q, scan_10_n_0, scan_10_q, scan_11_n_0,
       scan_11_q, scan_12_n_0, scan_12_q;
  wire scan_fix0_6_n_0, scan_fix0_6_n_1, scan_fix0_6_q,
       scan_fix0_8_n_6, scan_fix0_8_n_8, scan_fix0_8_n_14,
       scan_fix1_2_n_0, scan_fix1_2_q;
  df1qpdw scan_10_q_reg(.CP (clk), .D (scan_10_n_0), .Q (scan_10_q));
  mx21x2pdw scan_10_g22(.D0 (seed_inp[2]), .D1 (scan_10_q), .S0
       (scan), .Z (scan_10_n_0)); 

....

.....

==================================================

I wanted RTL compiler to take the above sinppet as

df1qpd scan_8_q_reg(.CP (clk), .D (seed_outp[2]), .Q (scan_8_q)); 

mx21x2pd scan_8_g20(.D0 (seed_inp[2]), .D1 (scan_8_q), .S0
       (scan), .Z (seed_outp[2]));

==================================================

Functionality wise both are same but I am getting unnconnected  in the netlist because of this issue..

 wire [2:0] seed_inp;
 wire [2:0] seed_outp;

Is as written in the RTL and scan_9* scan_10* etc are as written out by RTL compiler after synthesis.

Is there a way I can force the RTL compiler not to use its own wire names but to retain the wire names as written in RTL ?

 

Regards,

-DN

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  • grasshopper
    grasshopper over 13 years ago

     Hi DN,

     I believe you are looking for this

       attribute name: write_vlog_preserve_net_name
              category: write (controls write output)
           object type: root
           access type: read-write
             data type: boolean
         default value: false
                  help: Determines whether to preserve net names present in user input or not.

    Note that dangling wires resulting in incorrectly implemented functionality would be a bug in the tool. Did you run LEC ? I suspect if the wire became unconnected it probably could be optimized out but obviously I have no knowledge of RTL or functionality

     

    gh-

     

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  • deeps4
    deeps4 over 13 years ago

     Hi gh,

    I could not find that command in the manual. But some how that also did not help. May be I will try different version of RTL compiler and check.

    Thanks,

    DN

     

     

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  • deeps4
    deeps4 over 13 years ago

     Hi gh,

    The signal was getting optimized out. I have one generic question to you. How does these unconnected or optimised nets gets handled

     during PNR. I mean if the gate levels has few ports as "unconnected" how does this gets sorted out during further stages, will it be tied off?

     

    Regards,

    -DN

     

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  • Rameen
    Rameen over 4 years ago

    did you find the solution?I am facing same issue

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