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         /* temporary area used by FFI code generation */
  40         s64 long_long_return;
  41
  42         context(cell datastack_size, cell retainstack_size, cell callstack_size);
  43         ~context();
  44
  45         void reset_datastack();
  46         void reset_retainstack();
  47         void reset_callstack();
  48         void reset_context_objects();
  49         void reset();
  50         void fix_stacks();
  51
  52         cell peek()
  53         {
  54                 return *(cell *)datastack;
  55         }
  56
  57         void replace(cell tagged)
  58         {
  59                 *(cell *)datastack = tagged;
  60         }
  61
  62         cell pop()
  63         {
  64                 cell value = peek();
  65                 datastack -= sizeof(cell);
  66                 return value;
  67         }
  68
  69         void push(cell tagged)
  70         {
  71                 datastack += sizeof(cell);
  72                 replace(tagged);
  73         }
  74 };
  75
  76 VM_C_API context *new_context(factor_vm *parent);
  77 VM_C_API void delete_context(factor_vm *parent, context *old_context);
  78 VM_C_API cell begin_callback(factor_vm *parent, cell quot);
  79 VM_C_API void end_callback(factor_vm *parent);
  80
  81 }