vm/contexts.hpp

   1 namespace factor
   2 {
   3
   4 static const cell context_object_count = 10;
   5
   6 enum context_object {
   7         OBJ_NAMESTACK,
   8         OBJ_CATCHSTACK,
   9         OBJ_CONTEXT,
  10 };
  11
  12 static const cell stack_reserved = 1024;
  13
  14 struct context {
  15
  16         // First 4 fields accessed directly by compiler. See basis/vm/vm.factor
  17
  18         /* Factor callstack pointers */
  19         stack_frame *callstack_top;
  20         stack_frame *callstack_bottom;
  21
  22         /* current datastack top pointer */
  23         cell datastack;
  24
  25         /* current retain stack top pointer */
  26         cell retainstack;
  27
  28         /* C callstack pointer */
  29         cell callstack_save;
  30
  31         segment *datastack_seg;
  32         segment *retainstack_seg;
  33         segment *callstack_seg;
  34
  35         /* context-specific special objects, accessed by context-object and
  36         set-context-object primitives */
  37         cell context_objects[context_object_count];
  38
  39         context(cell datastack_size, cell retainstack_size, cell callstack_size);
  40         ~context();
  41
  42         void reset_datastack();
  43         void reset_retainstack();
  44         void reset_callstack();
  45         void reset_context_objects();
  46         void reset();
  47         void fix_stacks();
  48         void scrub_stacks(gc_info *info, cell index);
  49
  50         cell peek()
  51         {
  52                 return *(cell *)datastack;
  53         }
  54
  55         void replace(cell tagged)
  56         {
  57                 *(cell *)datastack = tagged;
  58         }
  59
  60         cell pop()
  61         {
  62                 cell value = peek();
  63                 datastack -= sizeof(cell);
  64                 return value;
  65         }
  66
  67         void push(cell tagged)
  68         {
  69                 datastack += sizeof(cell);
  70                 replace(tagged);
  71         }
  72 };
  73
  74 VM_C_API context *new_context(factor_vm *parent);
  75 VM_C_API void delete_context(factor_vm *parent, context *old_context);
  76 VM_C_API cell begin_callback(factor_vm *parent, cell quot);
  77 VM_C_API void end_callback(factor_vm *parent);
  78
  79 }