ASIC/FPGA Design and Verification Out Source Services

PERL script to split a VCD, wave format, file.

1. VCD is a format that all wave viewer read. I use it a lot, to allow me to debug using the free wave tool GTKWAVE. At home because I can not afford buying a simulator. At work sometimes there is a license shortage and then GTKWAVE comes to the rescue.


2. Sometimes there are many details (in terms of simulation time and signals), which results in a very big file and it is better to work on smaller files. When I work at home this becomes even more important. The home computer is not too strong to cope with big data bases and sometimes the VCD is downloaded from work office, so smaller files means less wait time.


3. The following script splits a VCD file by two simple steps. The spilt is done based on simulation time.


4. First it looks to the place,in file, where time info starts, by searching for the string:
   enddefinitions.


5. Last it reads the simulation time and if in range, specified by the PERL script input parameters, ARGV[1] and ARGV[2], it writes to the new file.


6. It may take long process time for the script to finish the job. So one may want to add at the end of the script the following lines:
   


1. #print perl time
   
2. $t=time - $^T;
   
3. print("$t\n");
   


7. The PERL code, for this example, is available for free at the user own risk vcd split Script .

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