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,false)),
  13         retainstack_seg(new segment(retainstack_size,false,false)),
  14         callstack_seg(new segment(callstack_size,false,true))
  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 void context::scrub_stacks(gc_info *info, cell index)
  59 {
  60         u8 *bitmap = info->gc_info_bitmap();
  61
  62         {
  63                 cell base = info->callsite_scrub_d(index);
  64
  65                 for(cell loc = 0; loc < info->scrub_d_count; loc++)
  66                 {
  67                         if(bitmap_p(bitmap,base + loc))
  68                         {
  69 #ifdef DEBUG_GC_MAPS
  70                                 std::cout << "scrubbing datastack location " << loc << std::endl;
  71 #endif
  72                                 *((cell *)datastack - loc) = 0;
  73                         }
  74                 }
  75         }
  76
  77         {
  78                 cell base = info->callsite_scrub_r(index);
  79
  80                 for(cell loc = 0; loc < info->scrub_r_count; loc++)
  81                 {
  82                         if(bitmap_p(bitmap,base + loc))
  83                         {
  84 #ifdef DEBUG_GC_MAPS
  85                                 std::cout << "scrubbing retainstack location " << loc << std::endl;
  86 #endif
  87                                 *((cell *)retainstack - loc) = 0;
  88                         }
  89                 }
  90         }
  91 }
  92
  93 context::~context()
  94 {
  95         delete datastack_seg;
  96         delete retainstack_seg;
  97         delete callstack_seg;
  98 }
  99
 100 /* called on startup */
 101 void factor_vm::init_contexts(cell datastack_size_, cell retainstack_size_, cell callstack_size_)
 102 {
 103         datastack_size = datastack_size_;
 104         retainstack_size = retainstack_size_;
 105         callstack_size = callstack_size_;
 106
 107         ctx = NULL;
 108         spare_ctx = new_context();
 109 }
 110
 111 void factor_vm::delete_contexts()
 112 {
 113         assert(!ctx);
 114         std::list<context *>::const_iterator iter = unused_contexts.begin();
 115         std::list<context *>::const_iterator end = unused_contexts.end();
 116         while(iter != end)
 117         {
 118                 delete *iter;
 119                 iter++;
 120         }
 121 }
 122
 123 context *factor_vm::new_context()
 124 {
 125         context *new_context;
 126
 127         if(unused_contexts.empty())
 128         {
 129                 new_context = new context(datastack_size,
 130                         retainstack_size,
 131                         callstack_size);
 132         }
 133         else
 134         {
 135                 new_context = unused_contexts.back();
 136                 unused_contexts.pop_back();
 137         }
 138
 139         new_context->reset();
 140
 141         active_contexts.insert(new_context);
 142
 143         return new_context;
 144 }
 145
 146 void factor_vm::init_context(context *ctx)
 147 {
 148         ctx->context_objects[OBJ_CONTEXT] = allot_alien(ctx);
 149 }
 150
 151 context *new_context(factor_vm *parent)
 152 {
 153         context *new_context = parent->new_context();
 154         parent->init_context(new_context);
 155         return new_context;
 156 }
 157
 158 void factor_vm::delete_context(context *old_context)
 159 {
 160         unused_contexts.push_back(old_context);
 161         active_contexts.erase(old_context);
 162
 163         while(unused_contexts.size() > 10)
 164         {
 165                 context *stale_context = unused_contexts.front();
 166                 unused_contexts.pop_front();
 167                 delete stale_context;
 168         }
 169 }
 170
 171 VM_C_API void delete_context(factor_vm *parent, context *old_context)
 172 {
 173         parent->delete_context(old_context);
 174 }
 175
 176 VM_C_API void reset_context(factor_vm *parent, context *ctx)
 177 {
 178         ctx->reset();
 179         parent->init_context(ctx);
 180 }
 181
 182 cell factor_vm::begin_callback(cell quot_)
 183 {
 184         data_root<object> quot(quot_,this);
 185
 186         ctx->reset();
 187         spare_ctx = new_context();
 188         callback_ids.push_back(callback_id++);
 189
 190         init_context(ctx);
 191
 192         return quot.value();
 193 }
 194
 195 cell begin_callback(factor_vm *parent, cell quot)
 196 {
 197         return parent->begin_callback(quot);
 198 }
 199
 200 void factor_vm::end_callback()
 201 {
 202         callback_ids.pop_back();
 203         delete_context(ctx);
 204 }
 205
 206 void end_callback(factor_vm *parent)
 207 {
 208         parent->end_callback();
 209 }
 210
 211 void factor_vm::primitive_current_callback()
 212 {
 213         ctx->push(tag_fixnum(callback_ids.back()));
 214 }
 215
 216 void factor_vm::primitive_context_object()
 217 {
 218         fixnum n = untag_fixnum(ctx->peek());
 219         ctx->replace(ctx->context_objects[n]);
 220 }
 221
 222 void factor_vm::primitive_set_context_object()
 223 {
 224         fixnum n = untag_fixnum(ctx->pop());
 225         cell value = ctx->pop();
 226         ctx->context_objects[n] = value;
 227 }
 228
 229 void factor_vm::primitive_context_object_for()
 230 {
 231         context *other_ctx = (context *)pinned_alien_offset(ctx->pop());
 232         fixnum n = untag_fixnum(ctx->pop());
 233         ctx->push(other_ctx->context_objects[n]);
 234 }
 235
 236 cell factor_vm::stack_to_array(cell bottom, cell top)
 237 {
 238         fixnum depth = (fixnum)(top - bottom + sizeof(cell));
 239
 240         if(depth < 0)
 241                 return false_object;
 242         else
 243         {
 244                 array *a = allot_uninitialized_array<array>(depth / sizeof(cell));
 245                 memcpy(a + 1,(void*)bottom,depth);
 246                 return tag<array>(a);
 247         }
 248 }
 249
 250 cell factor_vm::datastack_to_array(context *ctx)
 251 {
 252         cell array = stack_to_array(ctx->datastack_seg->start,ctx->datastack);
 253         if(array == false_object)
 254         {
 255                 general_error(ERROR_DATASTACK_UNDERFLOW,false_object,false_object);
 256                 return false_object;
 257         }
 258         else
 259                 return array;
 260 }
 261
 262 void factor_vm::primitive_datastack()
 263 {
 264         ctx->push(datastack_to_array(ctx));
 265 }
 266
 267 void factor_vm::primitive_datastack_for()
 268 {
 269         context *other_ctx = (context *)pinned_alien_offset(ctx->pop());
 270         ctx->push(datastack_to_array(other_ctx));
 271 }
 272
 273 cell factor_vm::retainstack_to_array(context *ctx)
 274 {
 275         cell array = stack_to_array(ctx->retainstack_seg->start,ctx->retainstack);
 276         if(array == false_object)
 277         {
 278                 general_error(ERROR_RETAINSTACK_UNDERFLOW,false_object,false_object);
 279                 return false_object;
 280         }
 281         else
 282                 return array;
 283 }
 284
 285 void factor_vm::primitive_retainstack()
 286 {
 287         ctx->push(retainstack_to_array(ctx));
 288 }
 289
 290 void factor_vm::primitive_retainstack_for()
 291 {
 292         context *other_ctx = (context *)pinned_alien_offset(ctx->pop());
 293         ctx->push(retainstack_to_array(other_ctx));
 294 }
 295
 296 /* returns pointer to top of stack */
 297 cell factor_vm::array_to_stack(array *array, cell bottom)
 298 {
 299         cell depth = array_capacity(array) * sizeof(cell);
 300         memcpy((void*)bottom,array + 1,depth);
 301         return bottom + depth - sizeof(cell);
 302 }
 303
 304 void factor_vm::set_datastack(context *ctx, array *array)
 305 {
 306         ctx->datastack = array_to_stack(array,ctx->datastack_seg->start);
 307 }
 308
 309 void factor_vm::primitive_set_datastack()
 310 {
 311         set_datastack(ctx,untag_check<array>(ctx->pop()));
 312 }
 313
 314 void factor_vm::set_retainstack(context *ctx, array *array)
 315 {
 316         ctx->retainstack = array_to_stack(array,ctx->retainstack_seg->start);
 317 }
 318
 319 void factor_vm::primitive_set_retainstack()
 320 {
 321         set_retainstack(ctx,untag_check<array>(ctx->pop()));
 322 }
 323
 324 /* Used to implement call( */
 325 void factor_vm::primitive_check_datastack()
 326 {
 327         fixnum out = to_fixnum(ctx->pop());
 328         fixnum in = to_fixnum(ctx->pop());
 329         fixnum height = out - in;
 330         array *saved_datastack = untag_check<array>(ctx->pop());
 331         fixnum saved_height = array_capacity(saved_datastack);
 332         fixnum current_height = (ctx->datastack - ctx->datastack_seg->start + sizeof(cell)) / sizeof(cell);
 333         if(current_height - height != saved_height)
 334                 ctx->push(false_object);
 335         else
 336         {
 337                 cell *ds_bot = (cell *)ctx->datastack_seg->start;
 338                 for(fixnum i = 0; i < saved_height - in; i++)
 339                 {
 340                         if(ds_bot[i] != array_nth(saved_datastack,i))
 341                         {
 342                                 ctx->push(false_object);
 343                                 return;
 344                         }
 345                 }
 346                 ctx->push(true_object);
 347         }
 348 }
 349
 350 void factor_vm::primitive_load_locals()
 351 {
 352         fixnum count = untag_fixnum(ctx->pop());
 353         memcpy((cell *)(ctx->retainstack + sizeof(cell)),
 354                 (cell *)(ctx->datastack - sizeof(cell) * (count - 1)),
 355                 sizeof(cell) * count);
 356         ctx->datastack -= sizeof(cell) * count;
 357         ctx->retainstack += sizeof(cell) * count;
 358 }
 359
 360 }