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 VM_C_API void delete_context(factor_vm *parent, context *old_context)
 123 {
 124         parent->delete_context(old_context);
 125 }
 126
 127 void factor_vm::begin_callback()
 128 {
 129         ctx->reset();
 130         spare_ctx = new_context();
 131         callback_ids.push_back(callback_id++);
 132 }
 133
 134 void begin_callback(factor_vm *parent)
 135 {
 136         parent->begin_callback();
 137 }
 138
 139 void factor_vm::end_callback()
 140 {
 141         callback_ids.pop_back();
 142         delete_context(ctx);
 143 }
 144
 145 void end_callback(factor_vm *parent)
 146 {
 147         parent->end_callback();
 148 }
 149
 150 void factor_vm::primitive_current_callback()
 151 {
 152         ctx->push(tag_fixnum(callback_ids.back()));
 153 }
 154
 155 void factor_vm::primitive_context_object()
 156 {
 157         fixnum n = untag_fixnum(ctx->peek());
 158         ctx->replace(ctx->context_objects[n]);
 159 }
 160
 161 void factor_vm::primitive_set_context_object()
 162 {
 163         fixnum n = untag_fixnum(ctx->pop());
 164         cell value = ctx->pop();
 165         ctx->context_objects[n] = value;
 166 }
 167
 168 void factor_vm::primitive_context_object_for()
 169 {
 170         context *other_ctx = (context *)pinned_alien_offset(ctx->pop());
 171         fixnum n = untag_fixnum(ctx->pop());
 172         ctx->push(other_ctx->context_objects[n]);
 173 }
 174
 175 cell factor_vm::stack_to_array(cell bottom, cell top)
 176 {
 177         fixnum depth = (fixnum)(top - bottom + sizeof(cell));
 178
 179         if(depth < 0)
 180                 return false_object;
 181         else
 182         {
 183                 array *a = allot_uninitialized_array<array>(depth / sizeof(cell));
 184                 memcpy(a + 1,(void*)bottom,depth);
 185                 return tag<array>(a);
 186         }
 187 }
 188
 189 cell factor_vm::datastack_to_array(context *ctx)
 190 {
 191         cell array = stack_to_array(ctx->datastack_seg->start,ctx->datastack);
 192         if(array == false_object)
 193         {
 194                 general_error(ERROR_DATASTACK_UNDERFLOW,false_object,false_object);
 195                 return false_object;
 196         }
 197         else
 198                 return array;
 199 }
 200
 201 void factor_vm::primitive_datastack()
 202 {
 203         ctx->push(datastack_to_array(ctx));
 204 }
 205
 206 void factor_vm::primitive_datastack_for()
 207 {
 208         context *other_ctx = (context *)pinned_alien_offset(ctx->pop());
 209         ctx->push(datastack_to_array(other_ctx));
 210 }
 211
 212 cell factor_vm::retainstack_to_array(context *ctx)
 213 {
 214         cell array = stack_to_array(ctx->retainstack_seg->start,ctx->retainstack);
 215         if(array == false_object)
 216         {
 217                 general_error(ERROR_RETAINSTACK_UNDERFLOW,false_object,false_object);
 218                 return false_object;
 219         }
 220         else
 221                 return array;
 222 }
 223
 224 void factor_vm::primitive_retainstack()
 225 {
 226         ctx->push(retainstack_to_array(ctx));
 227 }
 228
 229 void factor_vm::primitive_retainstack_for()
 230 {
 231         context *other_ctx = (context *)pinned_alien_offset(ctx->pop());
 232         ctx->push(retainstack_to_array(other_ctx));
 233 }
 234
 235 /* returns pointer to top of stack */
 236 cell factor_vm::array_to_stack(array *array, cell bottom)
 237 {
 238         cell depth = array_capacity(array) * sizeof(cell);
 239         memcpy((void*)bottom,array + 1,depth);
 240         return bottom + depth - sizeof(cell);
 241 }
 242
 243 void factor_vm::set_datastack(context *ctx, array *array)
 244 {
 245         ctx->datastack = array_to_stack(array,ctx->datastack_seg->start);
 246 }
 247
 248 void factor_vm::primitive_set_datastack()
 249 {
 250         set_datastack(ctx,untag_check<array>(ctx->pop()));
 251 }
 252
 253 void factor_vm::set_retainstack(context *ctx, array *array)
 254 {
 255         ctx->retainstack = array_to_stack(array,ctx->retainstack_seg->start);
 256 }
 257
 258 void factor_vm::primitive_set_retainstack()
 259 {
 260         set_retainstack(ctx,untag_check<array>(ctx->pop()));
 261 }
 262
 263 /* Used to implement call( */
 264 void factor_vm::primitive_check_datastack()
 265 {
 266         fixnum out = to_fixnum(ctx->pop());
 267         fixnum in = to_fixnum(ctx->pop());
 268         fixnum height = out - in;
 269         array *saved_datastack = untag_check<array>(ctx->pop());
 270         fixnum saved_height = array_capacity(saved_datastack);
 271         fixnum current_height = (ctx->datastack - ctx->datastack_seg->start + sizeof(cell)) / sizeof(cell);
 272         if(current_height - height != saved_height)
 273                 ctx->push(false_object);
 274         else
 275         {
 276                 cell *ds_bot = (cell *)ctx->datastack_seg->start;
 277                 for(fixnum i = 0; i < saved_height - in; i++)
 278                 {
 279                         if(ds_bot[i] != array_nth(saved_datastack,i))
 280                         {
 281                                 ctx->push(false_object);
 282                                 return;
 283                         }
 284                 }
 285                 ctx->push(true_object);
 286         }
 287 }
 288
 289 void factor_vm::primitive_load_locals()
 290 {
 291         fixnum count = untag_fixnum(ctx->pop());
 292         memcpy((cell *)(ctx->retainstack + sizeof(cell)),
 293                 (cell *)(ctx->datastack - sizeof(cell) * (count - 1)),
 294                 sizeof(cell) * count);
 295         ctx->datastack -= sizeof(cell) * count;
 296         ctx->retainstack += sizeof(cell) * count;
 297 }
 298
 299 void factor_vm::primitive_context()
 300 {
 301         ctx->push(allot_alien(ctx));
 302 }
 303
 304 }