See below for man page (as of Nov '25). The current version is available here. Relevant project page. Modelgen-verilog implementation notes are here.

GNUCAP-MG-VAMS(1)               Gnucap Modelgen               GNUCAP-MG-VAMS(1)

NAME
       gnucap-mg-vams - GNU Circuit Analysis Package .vams translator

SYNOPSIS
       gnucap-mg-vams { [OPTIONS] [ACTIONS] }

DESCRIPTION
       Gnucap-Modelgen is a translator tool in the Gnucap suite. It will trans‐
       form Verilog-AMS models into C++ code implementing Gnucap component plu‐
       gins.

       Basic  usage  (with  bash,  on a posix system) may look as follows.  For
       more examples, see the examples directory.

       $ gnucap-mg-vams -I path/to/include -o mymodel.cc --cc mymodel.vams
       $ g++ `gnucap-conf --cppflags` -fPIC -shared mymodel.cc -o mymodel.so
       $ gnucap -a ./mymodel.so -a mgsim
       gnucap> ...

       The mgsim directory contains the plugins used when  simulating  modelgen
       models.

       The  following  options,  actions  and  pragmas  are supported, they are
       processed in the order specified at the command line.

OPTIONS
       -I path
              Set preprocessor include path, relative to cwd.

       -D "name value" | -D name=value
              Set preprocessor constant.

       -o "filename"
              Send output to filename (default: stdout).

       --flag | --noflag
              Various flags, under construction,  see  mg_options.{h,cc}.  Also
              available through `pragma during preprocessing.

       -a plugin
              Load  plugin,  add  and  replace  functionality.  Example plugin:
              mgopt/nonoise.so.

ACTIONS
       --pp   dump preprocessor output

       --dump dump contents as parsed

       --cc   generate c++ file

PRAGMAS
       Pragmas control the behaviour of the program. The preprocessor  supports
       the `pragma command, and will act upon pragmas directed to "modelgen".

       --{pragma_name}
              enables  pragma  the way `pragma modelgen {pragma_name} does. But
              in the order specified at command line.

       --gen-module | --nogen-module
              Affects --cc. Generate (no) code for devices specified  in  terms
              of a "module".

       --gen-paramset | --nogen-paramset
              Affects  --cc.  Generate (no) code for devices specified in terms
              of a "paramset".

       --dump-module | --nodump-module
              Affects --dump. Output (no) source for "modules".

       --dump-paramset | --nodump-paramset
              Affects --dump. Output (no) source for "paramsets".

       --dump-annotate | --nodump-annotate
              Affects --dump. Annotate verilog code. Mostly for testing and de‐
              bugging.

       --debug | --log | --trace
              Set error level to "debug", "log" or "trace" respectively.

       [..] see mg_options.h

COMPILER FLAGS
       These may be passed to a/the  C++  compiler  supplementing  `gnucap-conf
       --cppflags`.

       -O0, -O2
              Turn on, off optimisation respectively. For details, consult your
              compiler manual.

       -g     Include  debugging  symbols.  For  details, consult your compiler
              manual.

       -DNDEBUG
              Drop debugging code, essentially run time assertions.  This  will
              speed up execution significantly.

       -DTRACE_UNTESTED
              Discover  test status. Untested code notification will be printed
              to standard error output.

       -DTRACE_ITESTED
              Similar, but notify about interactively tested code.

EXAMPLES
       Basic Verilog-AMS models are included with this package,  covering  some
       of the primitives listed in Table E.1 of the LRM 2.4.0.

       For  general usage, see examples directory shipped with modelgen-verilog
       source code.

BUGS
       This is under construction. Expect bugs, see BUGS.

AUTHOR
       Gnucap-mg-vams is being written by Felix Salfelder and Albert Davis with
       financial support from NLnet Next Generation Internet programme.

       This manual page was written by Felix  Salfelder  <felix@salfelder.org>.
       For the full documentation, visit http://gnucap.org.

Gnucap Project                      May 2023                  GNUCAP-MG-VAMS(1)