Management of Statically Modifiable Prolog Code

The Warren Abstract Machine is an efficient execution model for Prolog, which has become the basis of many high performance Prolog systems. However, little support for the implementation of the non-logical components of Prolog is provided in the WAM. The original Warren code is not modifiable. In this paper, we show how static modifications of Warren code can be achieved by adding a few instructions and a little extra information to the code. The implementation of the code manager is discussed. Algorithms for some basic operations are given.