Although they use different representations, the two types of predicates can call each other freely. The SICStus Prolog compiler produces compact and efficient code, running about 8 times faster than consulted code, and requiring much less runtime storage. Compiled Prolog programs are comparable in efficiency with LISP programs for the same task. However, against this, compilation itself takes about twice as long as consulting, and tracing of goals that compile in-line are not available in compiled code. This is the default unless SICStus Prolog has been installed with support for fastcode compilation.
Compilation produces native machine instructions.
Currently only available for 68K, Sparc and MIPS platforms, but not for Muse. Fastcode runs about 3 times faster than compactcode. This is the default if SICStus Prolog has been installed with support for fastcode compilation. Compilation produces byte-coded abstract instructions instrumented to produce execution profiling data. See section Execution Profiling .