vvp(1)								  Version 0.9.5 							    vvp(1)

NAME

       vvp - Icarus Verilog vvp runtime engine

SYNOPSIS

       vvp [-sv] [-Mpath] [-mmodule] [-llogfile] inputfile [extended-args...]

DESCRIPTION

       vvp is the run time engine that executes the default compiled form generated by Icarus Verilog. The output from the iverilog command is not
       by itself executable on any platform. Instead, the vvp program is invoked to execute the generated output file.

OPTIONS

       vvp accepts the following options:

       -llogfile
	       This flag specifies a logfile where all MCI <stdlog> output goes.  Specify logfile as '-' to send log output to <stderr>.  $display
	       and friends send their output both to <stdout> and <stdlog>.

       -Mpath  This  flag  adds  a directory to the path list used to locate VPI modules. The default path includes only the install directory for
	       the system.vpi module, but this flag can add other directories. Multiple paths are allowed, and modules will be searched in order.

       -mmodule
	       Tell the vvp run time to load the named module before executing the simulation. The system.vpi module is  loaded  by  default,  but
	       additional  modules,  including	modules  that  you compiled locally, can be specified with this flag. Any number of modules can be
	       loaded, and they will be linked in the order they are listed on the command line.

	       Normally, you only need to specify the name of the module, without any directory path or .vpi suffix and the search path is scanned
	       to  find  the  module.  However, if the name includes at least one directory character, then the search path is not scanned and the
	       name is assumed to be a complete file name.

       -n      This flag makes $stop or a <Control-C> a synonym for $finish.  It can be used to give the program a more meaningful interface  when
	       running in a non-interactive environment.

       -N      This flag does the same thing as -n, but results in an exit code of 1 if the stimulation calls $stop.  It can be used to indicate a
	       simulation failure when running a testbench.

       -s      Stop. This will cause the simulation to stop in the beginning, before any events are scheduled. This allows the interactive user to
	       get hold of the simulation just before it starts.

       -v      Turn on verbose messages. This will cause information about run time progress to be printed to standard out.

       -V      Print the version of the runtime, and exit.

EXTENDED ARGUMENTS

       The  vvp  options  described  above must come before the design file name.  After the design file name, however, there may be any number of
       unspecified arguments. These arguments are not interpreted by vvp but are instead passed on to the executed design, and are  available  via
       the $test$plusargs and $value$plusargs system functions.

       Arguments  that	do not start with the plus(+) character are not available to the $plusargs system tasks, but can still be accessed via PLI
       code via the vpi_get_vlog_info function. This means that vpi modules may use arguments that do not start with + and be assured that they do
       not interfere with user defined plus-args.

       There  are  a few extended arguments that are interpreted by the standard system.vpi module, which implements the standard system tasks and
       so is always included. These arguments are described here.

       -vcd    This extended argument sets the wave dump format to VCD. This is the default in the  absence  of  any  IVERILOG_DUMPER  environment
	       variable.  The  VCD dump files are large and ponderous, but are also maximally compatible with third party tools that read waveform
	       dumps.

       -lxt|-lxt-speed|-lxt-space
	       These extended arguments set the wave dump format to lxt, possibly with format optimizations. The -lxt-space flag sets  the  output
	       format  to  lxt with full compression enabled. The resulting files are quite small. The -lxt-speed chooses the lxt compression mode
	       that leads to the best execution time and the fastest read time, at the expense of some file size.

       -lxt2|-lx2
	       The LXT2 format is slower then LXT (faster then VCD) but takes less space, and is written out incrementally.  Thus,  you  can  view
	       lxt2  files  while  a  simulation  is still running (or paused) or if your simulation crashes or is killed, you still have a useful
	       dump.

       -none   This flag can be used by itself or appended to the end of the above dumpers (vcd/lxt/lxt2/lx2) to  suppress  all  waveform  output.
	       This can make long simulations run faster.

       -sdf-warn
	       When loading an SDF annotation file, this option causes the annotator to print warnings for questionable but non-fatal issues.

       -sdf-info
	       When loading an SDF annotation file, this option causes the annotator to print information about the annotation.

       -sdf-verbose
	       This is shorthand for -sdf-info -sdf-warn.

ENVIRONMENT

       The vvp command also accepts some environment variables that control its behavior. These can be used to make semi-permanent changes.

       IVERILOG_DUMPER=lxt|lxt2|lx2|vcd|none
	       This selects the output format for the waveform output. Normally, waveforms are dumped in vcd format, but this variable can be used
	       to select lxt format, which is far more compact, though limited to gtkwave or compatible viewers. It can also be used  to  suppress
	       VCD output, a time-saver for regression tests.

INTERACTIVE MODE

       The  simulation	engine supports an interactive mode. The user may interrupt the simulation (typically by typing <Control-C>) to get to the
       interactive prompt. From that prompt, the help command prints a brief summary of the available commands.

       The interactive mode may also be entered by a call to the $stop system task from within the simulation, or by a call to the vpi_control VPI
       function with the vpiStop control argument. These means of entering interactive mode are equivalent.

AUTHOR

       Steve Williams (steve@icarus.com)

SEE ALSO

       iverilog(1), iverilog-vpi(1), <http://www.icarus.com/eda/verilog/>

COPYRIGHT

       Copyright (C)  2001-2009 Stephen Williams

       This document can be freely redistributed according to the terms of the
       GNU General Public License version 2.0

								 April 17th, 2009							    vvp(1)