|Table of Contents|
A Forth cross-compiler has many characteristics in common with an ANS Forth System, in that both use similar compiling tools to process a program. However, in order to fully specify an ANS Forth cross compiler it would be necessary to address complex issues dealing with compilation and execution semantics in both host and target environments as well as ROMability issues. The level of effort to do this properly has proved to be impractical at this time. As a result, although it may be possible for a Forth cross-compiler to correctly prepare an ANS Forth program for execution in a target environment, it is inappropriate for a cross-compiler to be labeled an ANS Forth System.
Because all programs require space for data and instructions, and time to execute those instructions, they depend on the presence of an environment providing those resources. It is impossible to predict how little of some of these resources (e.g. stack space) might be necessary to perform some task, so this Standard does not do so.
On the other hand, as a program requires increasing levels of resources, there will probably be sucessively fewer systems on which it will execute sucessfully. An algorithm requiring an array of 109 cells might run on fewer computers than one requiring only 103.
Since there is also no way of knowing what minimum level of resources will be implemented in a system useful for at least some tasks, any program performing real work labeled simply an ANS Forth Program is unlikely to be labeled correctly.