Front-end

The source language for the compiler is described in [App97]. TIGER is a ``simple but non-trivial language of the Algol family,'' lacking only the wide variety of data types that categorize more familiar languages such as C. A pre-existing front-end was modified to implement the bit-level operations needed to support most cryptographic algorithms. Several ``pseudo-functions'' were also added to the language to make available the values of the hardware key registers. The output of the front-end is an Intermediate Representation Tree (IR tree). It is possible to rewrite the front-end to generate IR trees from another source language (say, a C subset) with minimal changes to the back-end implemented in this project.