How to get started: Edit the Makefile. You should configure a few machine-dependencies and what compiler you want to use. The code works both with ANSI and K&R-C. Use -DNeedFunctionPrototypes to compile with, or -UNeedFunctionPrototypes to compile without, function prototypes in the header files. Make addtst The "add" program that will be compiled and run checks whether the basic math functions of the gsm library work with your compiler. If it prints anything to stderr, complain (to us). Edit inc/config.h. Make Local versions of the gsm library and the "compress"-like filters toast, untoast and tcat will be generated. If the compilation aborts because of a missing function, declaration, or header file, see if there's something in inc/config.h to work around it. If not, complain. Try it Grab an audio file from somewhere (raw u-law or Sun .au is fine, linear 16-bit in host byte order will do), copy it, toast it, untoast it, and listen to the result. The GSM-encoded and -decoded audio should have the quality of a good phone line. If the resulting audio is noisier than your original, or if you hear compression artifacts, complain; that's a bug in our software, not a bug in the GSM encoding standard itself. Installation You can install the gsm library interface, or the toast binaries, or both. Edit the Makefile Fill in the directories where you want to install the library, header files, manual pages, and binaries. Turn off the installation of one half of the distribution (i.e., gsm library or toast binaries) by not setting the corresponding directory root Makefile macro. make install will install the programs "toast" with two links named "tcat" and "untoast", and the gsm library "libgsm.a" with a "gsm.h" header file, and their respective manual pages. Optimizing This code was developed on a machine without an integer multiplication instruction, where we obtained the fastest result by replacing some of the integer multiplications with floating point multiplications. If your machine does multiply integers fast enough, leave USE_FLOAT_MUL undefined. The results should be the same in both cases. On machines with fast floating point arithmetic, defining both USE_FLOAT_MUL and FAST makes a run-time library option available that will (in a few crucial places) use ``native'' floating point operations rather than the bit-by-bit defined ones of the GSM standard. If you use this fast option, the outcome will not be bitwise identical to the results prescribed by the standard, but it is compatible with the standard encoding, and a user is unlikely to notice a difference. Bug Reports Please direct bug reports, questions, and comments to jutta@cs.tu-berlin.de and cabo@informatik.uni-bremen.de. Good luck, Jutta Degener, Carsten Bormann -- Copyright 1992, 1993, 1994, by Jutta Degener and Carsten Bormann, Technische Universitaet Berlin. See the accompanying file "COPYRIGHT" for details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.