ghdl - VHDL compiler/simulator

       This manual page was written by Wesley J. Landaker <wjl@icecavern.net>, for the Debian project  (but  may
       be  used by others). It is released under the same terms as GHDL, i.e. the GNU General Public License. It
       was modified by Tristan Gingold to include it in the GHDL sources.

                                                  Jan 14, 2018                                           GHDL(1)

       This  manual  page documents briefly the ghdl command.  This manual page was written for user of man, but
       is not as complete as the reference documentation.

       Instead, users should read the GHDL texinfo manual

       The Debian package supports installing multiple GHDL backends at the same time.  The GHDL executable ghdl
       is actually a wrapper that will execute the first installed backend it finds in  the  order  mcode,  gcc,
       llvm.  If you want to run GHDL with a specific backend you can directly run their executable, named ghdl-mcode,  ghdl-gcc  and  ghdl-llvm  respectively.   Alternatively,  you  can run ghdl with the GHDL_BACKEND
       environment variable set to mcode, gcc or llvm to select a backend.  If the backend  in  GHDL_BACKEND  is
       not  installed  or  invalid, the wrapper will silently revert to selecting the first installed backend it
       finds.

       ghdl - VHDL compiler/simulator

       This program follows the usual GNU command line syntax, with long options starting with two dashes (`-').
       A summary of the main modes and options is included below.  For a complete description, refer to the GHDL
       texinfo manual.

       Basic commands:

       -a     Analysis, i.e. ghdl-afile.vhdl-e     Elabortation, i.e. ghdl-eunit_name-r     Run: run the simulation, i.e. ghdl-runit_name-s     Syntax-check, i.e. ghdl-sfile.vhdl--clean
              Clean: remove generated files, i.e. ghdl--clean-h,--help
              Help, i.e. ghdl--help--version
              Version, i.e. ghdl--version

       Basic options:

       --work=NAME
              Name of the WORK library, i.e.  ghdl-a--work=foofoo.vhdl--std=STD
              Which VHDL standard (87|93|93c|00|02), i.e. ghdl-a--std=87old.vhdl--ieee=VER
              Which IEEE library (none|standard|synopsys|mentor), i.e. ghdl-a--ieee=synopsysbroken.vhdl--no-vital-checks
              Disable VITAL restriction checking, i.e. ghdl-a--no-vital-checksunsupported_vital.vhdl

       There are many more modes and options; please consult the documentation.

       Executables created by GHDL have addition simulation options. The most important ones are listed below:

       --help Show options for simulation and execution.

       --assert-level=LEVEL
              Assert level at which to stop simulation (none|note|warning|error|failure),  i.e.  ./touchy_design--assert-level=note--stop-time=TIME
              Stop simuation after TIME, i.e. ./design--stop-time=50ns--vcd=FILENAME
              Dump  VCD  to  FILENAME  (a  waveform  dump,  viewable with--for instance--gtkwave), i.e. ./design--vcd=design.vcd--sdf=[TYPE=]PATH=FILENAME
              Back annotate SDF onto design using TYPE (min|typ|max), instance PATH, and SDF file FILENAME, i.e.
              ./sdf_design--sdf=typ=top/inst=inst.sdf

gtkwave(1)

       The texinfo manual fully documents GHDL. You may also browse it at <https://ghdl.github.io/ghdl/>.

ghdl [command] [options] files...
       ghdl-gcc [command] [options] files...
       ghdl-llvm [command] [options] files...
       ghdl-mcode [command] [options] files...