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