4 /* Assembly code makes assumptions about the layout of this struct:
5 - callstack_top field is 0
6 - callstack_bottom field is 1
8 - retainstack field is 3 */
10 /* C stack pointer on entry */
11 stack_frame *callstack_top;
12 stack_frame *callstack_bottom;
14 /* current datastack top pointer */
17 /* current retain stack top pointer */
20 /* saved contents of ds register on entry to callback */
23 /* saved contents of rs register on entry to callback */
24 cell retainstack_save;
26 /* memory region holding current datastack */
27 segment *datastack_region;
29 /* memory region holding current retain stack */
30 segment *retainstack_region;
32 /* saved userenv slots on entry to callback */
34 cell current_callback_save;
39 #define ds_bot (stack_chain->datastack_region->start)
40 #define ds_top (stack_chain->datastack_region->end)
41 #define rs_bot (stack_chain->retainstack_region->start)
42 #define rs_top (stack_chain->retainstack_region->end)
48 PRIMITIVE(retainstack);
49 PRIMITIVE(set_datastack);
50 PRIMITIVE(set_retainstack);
51 PRIMITIVE(check_datastack);
54 VM_C_API void nest_stacks(factor_vm *vm);
55 VM_C_API void unnest_stacks(factor_vm *vm);