vm/contexts.cpp

   1 #include "master.hpp"
   2
   3 namespace factor
   4 {
   5
   6 context::context(cell datastack_size, cell retainstack_size, cell callstack_size) :
   7         callstack_top(NULL),
   8         callstack_bottom(NULL),
   9         datastack(0),
  10         retainstack(0),
  11         callstack_save(0),
  12         datastack_seg(new segment(datastack_size,false)),
  13         retainstack_seg(new segment(retainstack_size,false)),
  14         callstack_seg(new segment(callstack_size,false))
  15 {
  16         reset();
  17 }
  18
  19 void context::reset_datastack()
  20 {
  21         datastack = datastack_seg->start - sizeof(cell);
  22 }
  23
  24 void context::reset_retainstack()
  25 {
  26         retainstack = retainstack_seg->start - sizeof(cell);
  27 }
  28
  29 void context::reset_callstack()
  30 {
  31         callstack_top = callstack_bottom = CALLSTACK_BOTTOM(this);
  32 }
  33
  34 void context::reset_context_objects()
  35 {
  36         memset_cell(context_objects,false_object,context_object_count * sizeof(cell));
  37 }
  38
  39 void context::reset()
  40 {
  41         reset_datastack();
  42         reset_retainstack();
  43         reset_callstack();
  44         reset_context_objects();
  45 }
  46
  47 void context::fix_stacks()
  48 {
  49         if(datastack + sizeof(cell) < datastack_seg->start
  50                 || datastack + stack_reserved >= datastack_seg->end)
  51                 reset_datastack();
  52
  53         if(retainstack + sizeof(cell) < retainstack_seg->start
  54                 || retainstack + stack_reserved >= retainstack_seg->end)
  55                 reset_retainstack();
  56 }
  57
  58 context::~context()
  59 {
  60         delete datastack_seg;
  61         delete retainstack_seg;
  62         delete callstack_seg;
  63 }
  64
  65 /* called on startup */
  66 void factor_vm::init_contexts(cell datastack_size_, cell retainstack_size_, cell callstack_size_)
  67 {
  68         datastack_size = datastack_size_;
  69         retainstack_size = retainstack_size_;
  70         callstack_size = callstack_size_;
  71
  72         ctx = NULL;
  73         spare_ctx = new_context();
  74 }
  75
  76 void factor_vm::delete_contexts()
  77 {
  78         assert(!ctx);
  79         std::vector<context *>::const_iterator iter = unused_contexts.begin();
  80         std::vector<context *>::const_iterator end = unused_contexts.end();
  81         while(iter != end)
  82         {
  83                 delete *iter;
  84                 iter++;
  85         }
  86 }
  87
  88 context *factor_vm::new_context()
  89 {
  90         context *new_context;
  91
  92         if(unused_contexts.empty())
  93         {
  94                 new_context = new context(datastack_size,
  95                         retainstack_size,
  96                         callstack_size);
  97         }
  98         else
  99         {
 100                 new_context = unused_contexts.back();
 101                 unused_contexts.pop_back();
 102         }
 103
 104         new_context->reset();
 105
 106         active_contexts.insert(new_context);
 107
 108         return new_context;
 109 }
 110
 111 context *new_context(factor_vm *parent)
 112 {
 113         return parent->new_context();
 114 }
 115
 116 void factor_vm::delete_context(context *old_context)
 117 {
 118         unused_contexts.push_back(old_context);
 119         active_contexts.erase(old_context);
 120 }
 121
 122 void factor_vm::begin_callback()
 123 {
 124         ctx->reset();
 125         spare_ctx = new_context();
 126         callback_ids.push_back(callback_id++);
 127 }
 128
 129 void begin_callback(factor_vm *parent)
 130 {
 131         parent->begin_callback();
 132 }
 133
 134 void factor_vm::end_callback()
 135 {
 136         callback_ids.pop_back();
 137         delete_context(ctx);
 138 }
 139
 140 void end_callback(factor_vm *parent)
 141 {
 142         parent->end_callback();
 143 }
 144
 145 void factor_vm::primitive_current_callback()
 146 {
 147         ctx->push(tag_fixnum(callback_ids.back()));
 148 }
 149
 150 void factor_vm::primitive_context_object()
 151 {
 152         fixnum n = untag_fixnum(ctx->peek());
 153         ctx->replace(ctx->context_objects[n]);
 154 }
 155
 156 void factor_vm::primitive_set_context_object()
 157 {
 158         fixnum n = untag_fixnum(ctx->pop());
 159         cell value = ctx->pop();
 160         ctx->context_objects[n] = value;
 161 }
 162
 163 bool factor_vm::stack_to_array(cell bottom, cell top)
 164 {
 165         fixnum depth = (fixnum)(top - bottom + sizeof(cell));
 166
 167         if(depth < 0)
 168                 return false;
 169         else
 170         {
 171                 array *a = allot_uninitialized_array<array>(depth / sizeof(cell));
 172                 memcpy(a + 1,(void*)bottom,depth);
 173                 ctx->push(tag<array>(a));
 174                 return true;
 175         }
 176 }
 177
 178 void factor_vm::primitive_datastack()
 179 {
 180         if(!stack_to_array(ctx->datastack_seg->start,ctx->datastack))
 181                 general_error(ERROR_DATASTACK_UNDERFLOW,false_object,false_object);
 182 }
 183
 184 void factor_vm::primitive_retainstack()
 185 {
 186         if(!stack_to_array(ctx->retainstack_seg->start,ctx->retainstack))
 187                 general_error(ERROR_RETAINSTACK_UNDERFLOW,false_object,false_object);
 188 }
 189
 190 /* returns pointer to top of stack */
 191 cell factor_vm::array_to_stack(array *array, cell bottom)
 192 {
 193         cell depth = array_capacity(array) * sizeof(cell);
 194         memcpy((void*)bottom,array + 1,depth);
 195         return bottom + depth - sizeof(cell);
 196 }
 197
 198 void factor_vm::primitive_set_datastack()
 199 {
 200         ctx->datastack = array_to_stack(untag_check<array>(ctx->pop()),ctx->datastack_seg->start);
 201 }
 202
 203 void factor_vm::primitive_set_retainstack()
 204 {
 205         ctx->retainstack = array_to_stack(untag_check<array>(ctx->pop()),ctx->retainstack_seg->start);
 206 }
 207
 208 /* Used to implement call( */
 209 void factor_vm::primitive_check_datastack()
 210 {
 211         fixnum out = to_fixnum(ctx->pop());
 212         fixnum in = to_fixnum(ctx->pop());
 213         fixnum height = out - in;
 214         array *saved_datastack = untag_check<array>(ctx->pop());
 215         fixnum saved_height = array_capacity(saved_datastack);
 216         fixnum current_height = (ctx->datastack - ctx->datastack_seg->start + sizeof(cell)) / sizeof(cell);
 217         if(current_height - height != saved_height)
 218                 ctx->push(false_object);
 219         else
 220         {
 221                 cell *ds_bot = (cell *)ctx->datastack_seg->start;
 222                 for(fixnum i = 0; i < saved_height - in; i++)
 223                 {
 224                         if(ds_bot[i] != array_nth(saved_datastack,i))
 225                         {
 226                                 ctx->push(false_object);
 227                                 return;
 228                         }
 229                 }
 230                 ctx->push(true_object);
 231         }
 232 }
 233
 234 void factor_vm::primitive_load_locals()
 235 {
 236         fixnum count = untag_fixnum(ctx->pop());
 237         memcpy((cell *)(ctx->retainstack + sizeof(cell)),
 238                 (cell *)(ctx->datastack - sizeof(cell) * (count - 1)),
 239                 sizeof(cell) * count);
 240         ctx->datastack -= sizeof(cell) * count;
 241         ctx->retainstack += sizeof(cell) * count;
 242 }
 243
 244 void factor_vm::primitive_context()
 245 {
 246         ctx->push(allot_alien(ctx));
 247 }
 248
 249 void factor_vm::primitive_delete_context()
 250 {
 251         context *old_context = (context *)pinned_alien_offset(ctx->pop());
 252         delete_context(old_context);
 253 }
 254
 255 }