CMUCL has four spaces, read-only, static, dynamic-0, and dynamic-1. Read-only contains objects that the system never modifies, moves, or reclaims. Static space contains some global objects necessary for the system’s runtime or performance (since they are located at a known offset at a known address), and the system never moves or reclaims these. However, GC does need to scan static space for references to moved objects. Dynamic-0 and dynamic-1 are the two heap areas for stop-and-copy GC algorithms.
What global objects are at the head of static space???
NIL eval::*top-of-stack* lisp::*current-catch-block* lisp::*current-unwind-protect* FLAGS (RT only) BSP (RT only) HEAP (RT only)
In addition to the above spaces, the system has a control stack, binding stack, and a number stack. The binding stack contains pairs of descriptors, a symbol and its previous value. The number stack is the same as the C stack, and the system uses it for non-Lisp objects such as raw system pointers, saving non-Lisp registers, parts of bignum computations, etc.