User guide

7-2

VCD and VPD File Utilities

• The vcd2vpd Utility

• The vpd2vcd Utility

• The vpdmerge Utility

The vcdpost Utility

You use the vcdpost utility to generate an alternative VCD file that

has the following characteristics:

• Contains value change and transition times for each bit of a vector

net or register, recorded as a separate signal. This is called

“scalarizing” the vector signals in the VCD file.

• Avoids sharing the same VCD identifier code with more than one

net or register. This is called “uniquifying” the identifier codes.

Scalarizing the Vector Signals

The VCD format does not support a mechanism to dump part of a

vector. For this reason, if you enter a bit select or a part select for a

net or register as an argument to the $dumpvars system task, VCS

records value changes and transition times for the entire net or

source code:

$dumpvars(1,mid1.out1[0]);

Here mid1.out1[0]is a bit select of a signal because you need to

examine the transition times and value changes of this bit. VCS

however writes a VCD file that contains the following: