1vvp(1) $Date: 2005/01/29 06:28:19 $ vvp(1)
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6 vvp - Icarus Verilog vvp runtime engine
7
10 vvp [-sv] [-Mpath] [-mmodule] [-llogfile] inputfile [extended-args...]
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14 vvp is the run time engine that executes the default compiled form gen‐
15 erated by Icarus Verilog. The output from the iverilog command is not
16 by itself executable on any platform. Instead, the vvp program is
17 invoked to execute the generated output file.
18
21 vvp accepts the following options:
22 -llogfile
24 This flag specifies a logfile where all MCI <stdlog> output
25 goes. Specify logfile as '-' to send log output to <stderr>.
26 $display and friends send their output both to <stdout> and
27 <stdlog>.
28 -Mpath This flag adds a directory to the path list used to locate VPI
30 modules. The default path includes only the install directory
31 for the system.vpi module, but this flag can add other directo‐
32 ries. Multiple paths are allowed, and modules will be searched
33 in order.
34 -mmodule
36 Tell the vvp run time to load the named module before executing
37 the simulation. The system.vpi module is loaded by default, but
38 additional modules, including modules that you compiled
39 locally, can be specified with this flag. Any number of modules
40 can be loaded, and they will be linked in the order they are
41 listed on the command line.
42 Normally, you only need to specify the name of the module,
44 without any directory path or .vpi suffix and the search path
45 is scanned to find the module. However, if the name includes at
46 least one directory character, then the search path is not
47 scanned and the name is assumed to be a complete file name.
48 -s Stop. This will cause the simulation to stop in the beginning,
50 before any events are scheduled. This allows the interactive
51 user to get hold of the simulation just before it starts.
52 -v Turn on verbose messages. This will cause information about run
54 time progress to be printed to standard out.
55
58 The vvp options described above must come before the design file name.
59 After the design file name, however, there may be any number of unspec‐
60 ified arguments. These arguments are not interpreted by vvp but are
61 instead passed on to the executed design, and are available via the
62 $test$plusargs and $value$plusargs system functions.
63 Arguments that do not start with the plus(+) character are not avail‐
65 able to the $plusargs system tasks, but can still be accessed via PLI
66 code via the vpi_get_vlog_info function. This means that vpi modules
67 may use arguments that do not start with + and be assured that they do
68 not interfere with user defined plus-args.
69 There are a few extended arguments that are interpreted by the standard
71 system.vpi module, which implements the standard system tasks and so is
72 always included. These arguments are described here.
73 -vcd|-vcd-none
75 This extended argument sets the wave dump format to VCD. This
76 is the default in the absence of any IVERILOG_DUMPER environ‐
77 ment variable. The VCD dump files are large and ponderous, but
78 are also maximally compatible with third party tools that read
79 waveform dumps.
80 The -vcd-none variant actually suppresses all waveform output. This can
82 make long simulations run faster.
83 -lxt|-lxt-speed|-lxt-space|-lxt-none
86 These extended arguments set the wave dump format to lxt, pos‐
87 sibly with format optimizations. The -lxt-space flag sets the
88 output format to lxt with full compression enabled. The result‐
89 ing files are quite small. The -lxt-speed chooses the lxt com‐
90 pression mode that leads to the best execution time and the
91 fastest read time, at the expense of some file size.
92 The -lxt-none variant actually suppresses all waveform output. This can
94 make long simulations run faster.
95 -lxt2 The LXT2 format is slower then LXT (faster then VCD) but takes
98 less space, and is written out incrementally. Thus, you can
99 view lxt2 files while a simulation is still running (or paused)
100 or if your simulation crashes or is killed, you still have a
101 useful dump.
102
105 The vvp command also accepts some environment variables that control
106 its behavior. These can be used to make semi-permanent changes.
107 IVERILOG_DUMPER=lxt|lxt2|vcd|none
110 This selects the output format for the waveform output. Nor‐
111 mally, waveforms are dumped in vcd format, but this variable
112 can be used to select lxt format, which is far more compact,
113 though limited to gtkwave or compatible viewers. It can also be
114 used to suppress VCD output, a time-saver for regression tests.
115
118 The simulation engine supports an interactive mode. The user may inter‐
119 rupt the simulation (typically by typing Ctrl-C) to get to the interac‐
120 tive prompt. From that prompt, the help command prints a brief summary
121 of the available commands.
122 The interactive mode may also be entered by a call to the $stop system
124 task from within the simulation, or by a call to the vpi_control VPI
125 function with the vpiStop control argument. These means of entering
126 interactive mode are equivalent.
127
130 Steve Williams (steve@icarus.com)
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134 iverilog(1), iverilog-vpi(1), <http://www.icarus.com/eda/verilog/>
135
138 Copyright © 2001-2003 Stephen Williams
139 This document can be freely redistributed according to the terms of the
141 GNU General Public License version 2.0
142Version $Date: 2005/01/29 06:28:19 $ vvp(1)