Prior to building the jbigi library, you will need to fetch the GMP source from http://www.swox.com/gmp/, saving it to jbigi/gmp-4.1.3.tar.bz2 (it will be unpacked and built as necessary). To build the native jbigi and jcpuid libraries for the current host CPU, simply run sh build.sh and the results will be packaged up into jbigi.jar To build the native jbigi libraries for all supported CPUs (on the current OS), go into jbigi/ and run build-all.sh (the results will be under jbigi/lib/)