On Aug 17, 10:34 am, Standish P <stnd...@gmail.com> wrote: > On Aug 16, 11:09 am, Elizabeth D Rather <erat...@forth.com> wrote: > > How are these heaps being implemented ? Is there some illustrative > code or a book showing how to implement these heaps in C for example ? > Forth does not use a heap, except maybe to implement malloc/free which many Forth apps do not use. The dictionary is a linked list structure. Now seems like a good time for you to teach yourself Forth (by studying the best commercial implementation you can find) since you seem to be working with a clean slate. But I will say a few things about stacks in general.
There are many ways to implement stacks. The simplest is to declare some space for the stack and then post-increment or pre-decrement a stack pointer depending on whether you're pushing or popping. Normally you make the memory for them big enough that they don't overflow. If you are concerned about stack overflow you can change the implementation. Add bounds checking, for example. Another trick is to use an 8-bit stack pointer. Then you will have a circular stack. If there is underflow or overflow it at least will not step on other data. It will only return bad data, which you may find preferable to an ugly crash. OTOH, bugs that cause spectacular failures tend to be discovered. You can also initialize the stack memory with a pattern like 0xDEAD and then after sufficiently exercising the code, examine the memory contents to see the "high water mark" of the stack pointer. -Brad -- http://mail.python.org/mailman/listinfo/python-list
