User guide

7-16
VCD and VPD File Utilities
-vgen
Generates from a VCD file two types of source files for a module
instance: one that models how the design applies stimulus to the
instance, and the other that models how the instance applies
stimulus to the rest of the design. See "Generating Source Files
From VCD Files" on page 7-17.
The following is an example of the output from the vcat utility:
vcat exp1.vcd
exp1.vcd: scopes:6 signals:12 value-changes:13
--- top.mid1.in1 ---
0 1
--- top.mid1.in2 ---
0 xxxxxxxx
10000 00000000
--- top.mid1.midr1 ---
0 x
2000 1
--- top.mid1.midr2 ---
0 x
2000 1
In this output you see, for example, that signal top.mid1.midr1 at time
0 had a value of X and at simulation time 2000 (as specified by the
$timescale section of the VCD file, which VCS derives from the
time precision argument of the ‘timescale compiler directive) this
signal transitioned to 1.