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https://github.com/nickg/nvc

VHDL compiler and simulator
https://github.com/nickg/nvc

compiler fpga simulator vhdl

Last synced: 3 months ago
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VHDL compiler and simulator

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README 

          
### Synopsis



[![Build Status](https://github.com/nickg/nvc/actions/workflows/build-test.yml/badge.svg?branch=master&event=push)](https://github.com/nickg/nvc/actions)

[![Coverage Status](https://coveralls.io/repos/github/nickg/nvc/badge.svg?branch=master)](https://coveralls.io/github/nickg/nvc?branch=master)



NVC is a [VHDL](https://en.wikipedia.org/wiki/VHDL) compiler and

simulator.



NVC supports almost all of VHDL-2008 with the exception of PSL, and it

has been successfully used to simulate several real-world designs.

Experimental support for Verilog and VHDL-2019 is under development.



NVC has a particular emphasis on simulation performance and uses

[LLVM](https://llvm.org/) to compile VHDL to native machine code.



NVC is not a synthesizer.  That is, it does not output something that

could be used to program an FPGA or ASIC.  It implements only the

simulation behaviour of the language as described by the [IEEE

1076](https://standards.ieee.org/standard/1076-2019.html) standard.



NVC supports popular verification frameworks including

[OSVVM](https://osvvm.org/), [UVVM](https://www.uvvm.org/),

[VUnit](https://vunit.github.io/) and [cocotb](https://www.cocotb.org/).

See [below](#vendor-libraries) for installation instructions.



### Usage



Simulating a VHDL hardware design involves three steps: _analysing_ the

source files; _elaborating_ the design; and _running_ the

simulation.  This is analogous to compiling, linking, and executing a

software program.  With NVC these steps are accomplished using the `-a`,

`-e`, and `-r` commands:



    $ nvc -a my_design.vhd my_tb.vhd

    $ nvc -e my_tb

    $ nvc -r my_tb



Or more succinctly, as a single command:



    $ nvc -a my_design.vhd my_tb.vhd -e my_tb -r



Where `my_tb` is the name of the top-level test-bench entity.



The full manual can be read after installation using `man nvc` or

[online](https://www.nickg.me.uk/nvc/manual.html).



### License



This program is [free

software](https://www.gnu.org/philosophy/free-sw.en.html) distributed

under the terms of the GNU General Public License version 3 or later.

You may use, modify, and redistribute the program as you wish but if you

distribute modifications you must preserve the license text and

copyright notices, and also make the modified source code available to

your users.



The source files for the IEEE standard libraries are included in the

repository.  These were originally provided under a proprietary license

that forbid distribution of modifications, but in 2019 were relicensed

under Apache 2.0.  Freely redistributable versions of the 1993 libraries

were made by editing and removing declarations from the 2019 libraries,

and so are also licensed under Apache 2.0.  Certain VHDL libraries

developed specifically for NVC under `lib/nvc` and `lib/std` are also

licensed under Apache 2.0.  See the individual files for details.



The VITAL libraries are distributed under `lib/vital`.  These were

derived from draft copies of the packages freely available on the

internet.  The license status of these is unclear as the final text is

part of the VITAL standard which must be purchased from the IEEE.  If

you are packaging this program for a distribution with strict free

software requirements you should strip these files from the tarball and

configure with `--disable-vital`.



### Installing



NVC is developed under GNU/Linux and is regularly tested on macOS and

Windows under MSYS2.



On macOS NVC can be installed with `brew install nvc`.  NVC is also

packaged for [FreeBSD](https://www.freshports.org/cad/nvc),

[Gentoo](https://packages.gentoo.org/packages/sci-electronics/nvc), Arch

Linux [AUR](https://aur.archlinux.org/packages/nvc), and [several other

distributions](https://repology.org/project/nvc/versions).  A Windows

installer is available from the [releases

page](https://github.com/nickg/nvc/releases/) and can be installed using

[winget](https://learn.microsoft.com/en-us/windows/package-manager/winget/)

with `winget install NickGasson.NVC`.  Users of systems without existing

packages should build from source.



For testing in GitHub Actions use

[setup-nvc](https://github.com/marketplace/actions/setup-nvc).  There is

also a Docker image

[ghcr.io/nickg/nvc](https://github.com/nickg/nvc/pkgs/container/nvc) for

other CI environments.



NVC has both a release branch and a development master branch. The

master branch should be stable enough for day-to-day use and has

comprehensive regression tests, but the release branch is more suitable

for third party packaging.  The latest released version is

[1.19.2](https://github.com/nickg/nvc/releases/tag/r1.19.2).

Significant changes since the last release are detailed in

[NEWS.md](NEWS.md).



If you are building from a Git clone rather than a released tarball you

first need to generate the configure script using:



    ./autogen.sh



In-tree builds are not supported so create a separate build directory:



    mkdir build && cd build



Finally build and install using the standard autotools steps:



    ../configure

    make

    sudo make install



To use a specific version of LLVM add `--with-llvm=/path/to/llvm-config`

to the configure command.  The minimum supported LLVM version is 8.0.

Versions between 8 and 21 have all been tested.



NVC also depends on Flex to generate the lexical analyser.



On a Debian derivative the following should be sufficient to install all

required dependencies:



    sudo apt-get install build-essential automake autoconf \

      flex check llvm-dev pkg-config zlib1g-dev libdw-dev \

      libffi-dev libzstd-dev



On `rpm` based distributions, the following can be installed to fulfill

required dependencies:



    sudo dnf install autoconf automake flex check llvm-devel libffi-devel \

      zlib-ng-compat-devel libzstd-devel elfutils-devel



Only the MSYS2 environment on Windows is supported.  The "Clang x64"

environment should be used because it supports native Windows

thread-local storage unlike the GCC-based environments.  The required

dependencies can be installed with:



    pacman -S base-devel mingw-w64-clang-x86_64-{llvm,ncurses,libffi,check,pkgconf,zstd,autotools,clang}



[GTKWave](http://gtkwave.sourceforge.net/) or [Surfer](https://surfer-project.org/)

can be used to view simulation waveforms.  For GTKWave, version 3.3.79 or later is

required for the default FST format.



#### Testing



To run the regression tests:



    make check



The unit tests require the [check](https://libcheck.github.io/check/)

library.



### Reporting bugs



Report bugs to [nick@nickg.me.uk](mailto:nick+nvc@nickg.me.uk) or using

the [GitHub issue tracker](https://github.com/nickg/nvc/issues).  Please

include enough information to reproduce the problem, ideally with a

small VHDL test case.  Issue

[#412](https://github.com/nickg/nvc/issues/412) is a good example.



Please remember that this software is provided to you with NO WARRANTY

and no expectation of support, but I will do my best to help with any

issues you encounter.



### Contributing



Patches can be sent as either pull requests on GitHub or by email using

[git --send-email](https://git-send-email.io/).  Please note however

that as this is purely a spare-time hobby project for me, I have limited

time available to review patches.  All code submitted must follow the

guidelines in [contrib/STYLE.md](contrib/STYLE.md).



I will not accept patches that add new copyright owners under `src/`.

This is to ensure there is clear legal ownership should, for example,

the license need to be updated.  Significant contributors are instead

listed in [THANKS.md](THANKS.md).



### Language Support



VHDL standard revisions are commonly referred to by the year they were

published.  For example IEEE 1076-2008 is known as VHDL-2008.  The

default standard in NVC is currently VHDL-2008 but this can be changed

with the `--std` argument.  For example `--std=1993` selects the

VHDL-1993 standard.



The 1993, 2000, and 2002 revisions of the standard are fully supported.

Please raise bugs for any missing or incorrectly implemented features

you encounter.  The current status of VHDL-2008 and VHDL-2019 support

can be found on the [features](https://www.nickg.me.uk/nvc/features.html)

page.



##### VHPI



The VHDL standard contains a comprehensive API called VHPI for

interfacing with foreign code written in C or another language.  NVC

implements a subset of VHPI sufficient for running

[cocotb](https://www.cocotb.org/).  Refer to the

[manual](https://www.nickg.me.uk/nvc/manual.html#VHPI) for more

information.



### Vendor Libraries



NVC provides scripts to compile popular verification frameworks and the

simulation libraries of common FPGA vendors.



* For [OSVVM](https://osvvm.org/) use `nvc --install osvvm`

* For [UVVM](https://www.uvvm.org/) use `nvc --install uvvm`

* For Xilinx ISE use `nvc --install ise`

* For Xilinx Vivado use `nvc --install vivado` and additionally `nvc

  --install xpm_vhdl` if you require simulation models of the XPM macros

* For Altera Quartus use `nvc --install quartus`

* For Lattice iCEcube2 use `nvc --install icecube2`

* For [Free Model Foundry](https://freemodelfoundry.com/) common

  packages use `nvc --install fmf`



The libraries will be installed under `~/.nvc/lib`.