A new GitHub organization was created (2017-12-20) and the main repo was moved from github.com/tgingold/ghdl to github.com/ghdl/ghdl. Old refs will continue working, because permanent redirects are set up. However, we suggest every contributor to update the remote URLs in their local clones. See Changing a remote's URL. This directory contains the sources of GHDL, the open-source compiler and simulator for VHDL, a Hardware Description Language (HDL). GHDL is not an interpreter: it allows you to analyse and elaborate sources to generate machine code from your design. Native program execution is the only way for high speed simulation.