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What does area reported by RTL compiler mean?

rexnyu

I compile my design to a 45nm library. RTL compiler gives me the following report:

 

   Type    Instances    Area    Area %
---------------------------------------
sequential      2237  19102.387   15.8
inverter        6982   9830.896    8.1
buffer           535   1255.847    1.0
logic          33180  91031.529   75.1
--------------------------------------- 

total 42934 121220.659 100.0 

 

I read the RTL compiler user mannual.  There is only one line explaining the meaning of "area":

"The area report gives a summary of the area of each component in the current design. The report gives the number of gates and the area size based on the specified technology library. Levels of hierarchy are indented in the report."

 

What does this mean in my case? So I will  multiply 45nm with to get 121220.659 an estimation of the area? 

 

Thank you! 

Parents
  • It is of um^2 but it is entirely library dependent

    The area number reported by 'report_area' is a unitless number in the library which may or may not be the same as um^2. The synthesis tool reports the area based on the numbers in the .lib file. The best way to figure out what this number means is to find a 2-input NAND gate in your library, find its area, and "normalize" it to that number.

    Let us say your NAND gate is called NAND2_A. To find its area of, do the following:

    get_attr area [find / -libcell NAND2_A]

    Then divide the area number from report area by this number to get NAND gate equivalents. Conversely, you can look in your LEF file for the actual area of this gate, and use that to estimate total area.

    Note: Starting in release 16.10, one can use the option -normalize_with_gate of the report area command to get the total area based on the cell area, for example:

    report area -normalize_with_gate NAND2_A

    hope it helps,
    gh-
  • in reply to grasshopper

    I am using Synopsys.  In Synopsys get_attr area [find / -libcell NAND2_A] command does not work. Can anyone tell an alternative solution to get  nand cell area

Reply Children
  • in reply to avais

    Your posts were in moderation (for some reason) - I approved just this one in order to reply. This forum is for Cadence tools, and this thread is specifically about RTL Compiler (a Cadence tool). Asking about a Synopsys tool makes no sense (especially in an old thread). You should ask the question in a Synopsys forum.

    I'll deny your other post to this same thread, as there's no point asking a second question about an off-topic subject.

    Andrew.

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