net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java

   1 package net.mograsim.logic.core.wires;\r
   2 \r
   3 import static net.mograsim.logic.core.types.Bit.U;\r
   4 import static net.mograsim.logic.core.types.Bit.Z;\r
   5 \r
   6 import java.util.ArrayList;\r
   7 import java.util.List;\r
   8 \r
   9 import net.mograsim.logic.core.LogicObservable;\r
  10 import net.mograsim.logic.core.LogicObserver;\r
  11 import net.mograsim.logic.core.timeline.Timeline;\r
  12 import net.mograsim.logic.core.types.Bit;\r
  13 import net.mograsim.logic.core.types.BitVector;\r
  14 import net.mograsim.logic.core.types.BitVector.BitVectorMutator;\r
  15 \r
  16 /**\r
  17  * Represents an array of wires that can store n bits of information.\r
  18  * \r
  19  * @author Fabian Stemmler\r
  20  *\r
  21  */\r
  22 public class Wire\r
  23 {\r
  24         private BitVector values;\r
  25         public final int travelTime;\r
  26         private List<ReadEnd> attached = new ArrayList<ReadEnd>();\r
  27         public final int length;\r
  28         private List<ReadWriteEnd> inputs = new ArrayList<ReadWriteEnd>();\r
  29         private Timeline timeline;\r
  30 \r
  31         public Wire(Timeline timeline, int length, int travelTime)\r
  32         {\r
  33                 if (length < 1)\r
  34                         throw new IllegalArgumentException(\r
  35                                         String.format("Tried to create an array of wires with length %d, but a length of less than 1 makes no sense.", length));\r
  36                 this.timeline = timeline;\r
  37                 this.length = length;\r
  38                 this.travelTime = travelTime;\r
  39                 initValues();\r
  40         }\r
  41 \r
  42         private void initValues()\r
  43         {\r
  44                 values = U.toVector(length);\r
  45         }\r
  46 \r
  47         private void recalculateSingleInput()\r
  48         {\r
  49                 setNewValues(inputs.get(0).getInputValues());\r
  50         }\r
  51 \r
  52         private void recalculateMultipleInputs()\r
  53         {\r
  54                 BitVectorMutator mutator = BitVectorMutator.empty();\r
  55                 for (ReadWriteEnd wireArrayEnd : inputs)\r
  56                         mutator.join(wireArrayEnd.getInputValues());\r
  57                 setNewValues(mutator.get());\r
  58         }\r
  59 \r
  60         private void setNewValues(BitVector newValues)\r
  61         {\r
  62                 if (values.equals(newValues))\r
  63                         return;\r
  64                 BitVector oldValues = values;\r
  65                 values = newValues;\r
  66                 notifyObservers(oldValues);\r
  67         }\r
  68 \r
  69         private void recalculate()\r
  70         {\r
  71                 switch (inputs.size())\r
  72                 {\r
  73                 case 0:\r
  74                         return;\r
  75                 case 1:\r
  76                         recalculateSingleInput();\r
  77                         break;\r
  78                 default:\r
  79                         recalculateMultipleInputs();\r
  80                 }\r
  81         }\r
  82 \r
  83         /**\r
  84          * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
  85          * \r
  86          * @return <code>true</code> if all bits are either <code>Bit.ONE</code> or <code>Bit.ZERO</code> (they do not all have to have the same\r
  87          *         value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.\r
  88          * \r
  89          * @author Fabian Stemmler\r
  90          */\r
  91         public boolean hasNumericValue()\r
  92         {\r
  93                 for (Bit b : values)\r
  94                 {\r
  95                         if (b != Bit.ZERO && b != Bit.ONE)\r
  96                                 return false;\r
  97                 }\r
  98                 return true;\r
  99         }\r
 100 \r
 101         /**\r
 102          * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 103          * \r
 104          * @return The unsigned value of the {@link Wire}'s bits, where value 0 corresponds with 2^0, value 1 is 2^1 and so on.\r
 105          * \r
 106          * @author Fabian Stemmler\r
 107          */\r
 108         public long getUnsignedValue()\r
 109         {\r
 110                 long val = 0;\r
 111                 long mask = 1;\r
 112                 for (Bit bit : values)\r
 113                 {\r
 114                         switch (bit)\r
 115                         {\r
 116                         default:\r
 117                         case Z:\r
 118                         case X:\r
 119                                 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;\r
 120                         case ONE:\r
 121                                 val |= mask;\r
 122                                 break;\r
 123                         case ZERO:\r
 124                         }\r
 125                         mask = mask << 1;\r
 126                 }\r
 127                 return val;\r
 128         }\r
 129 \r
 130         /**\r
 131          * The {@link Wire} is interpreted as a signed integer with n bits.\r
 132          * \r
 133          * @return The signed value of the {@link Wire}'s bits, where value 0 corresponds with 2^0, value 1 is 2^1 and so on.\r
 134          * \r
 135          * @author Fabian Stemmler\r
 136          */\r
 137         public long getSignedValue()\r
 138         {\r
 139                 long val = getUnsignedValue();\r
 140                 long mask = 1 << (length - 1);\r
 141                 if ((mask & val) != 0)\r
 142                 {\r
 143                         int shifts = 64 - length;\r
 144                         return (val << shifts) >> shifts;\r
 145                 }\r
 146                 return val;\r
 147         }\r
 148 \r
 149         public Bit getValue()\r
 150         {\r
 151                 return getValue(0);\r
 152         }\r
 153 \r
 154         public Bit getValue(int index)\r
 155         {\r
 156                 return values.getBit(index);\r
 157         }\r
 158 \r
 159         public BitVector getValues(int start, int end)\r
 160         {\r
 161                 return values.subVector(start, end);\r
 162         }\r
 163 \r
 164         public BitVector getValues()\r
 165         {\r
 166                 return values;\r
 167         }\r
 168 \r
 169         /**\r
 170          * Adds an {@link LogicObserver}, who will be notified when the value of the {@link Wire} is updated.\r
 171          * \r
 172          * @param ob The {@link LogicObserver} to be notified of changes.\r
 173          * @return true if the given {@link LogicObserver} was not already registered, false otherwise\r
 174          * \r
 175          * @author Fabian Stemmler\r
 176          */\r
 177         private void attachEnd(ReadEnd end)\r
 178         {\r
 179                 attached.add(end);\r
 180         }\r
 181 \r
 182         private void detachEnd(ReadEnd end)\r
 183         {\r
 184                 attached.remove(end);\r
 185         }\r
 186 \r
 187         private void notifyObservers(BitVector oldValues)\r
 188         {\r
 189                 for (ReadEnd o : attached)\r
 190                         o.update(oldValues);\r
 191         }\r
 192 \r
 193         /**\r
 194          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.\r
 195          */\r
 196         public ReadWriteEnd createReadWriteEnd()\r
 197         {\r
 198                 return new ReadWriteEnd();\r
 199         }\r
 200 \r
 201         /**\r
 202          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.\r
 203          */\r
 204         public ReadEnd createReadOnlyEnd()\r
 205         {\r
 206                 return new ReadEnd();\r
 207         }\r
 208 \r
 209         private void registerInput(ReadWriteEnd toRegister)\r
 210         {\r
 211                 inputs.add(toRegister);\r
 212         }\r
 213 \r
 214         /**\r
 215          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the\r
 216          * {@link Wire}s final value. X dominates all other inputs Z does not affect the final value, unless there are no other inputs than Z 0\r
 217          * and 1 turn into X when they are mixed\r
 218          * \r
 219          * @author Fabian Stemmler\r
 220          */\r
 221         public class ReadEnd implements LogicObservable\r
 222         {\r
 223                 private List<LogicObserver> observers = new ArrayList<LogicObserver>();\r
 224 \r
 225                 private ReadEnd()\r
 226                 {\r
 227                         super();\r
 228                         Wire.this.attachEnd(this);\r
 229                 }\r
 230 \r
 231                 public void update(BitVector oldValues)\r
 232                 {\r
 233                         notifyObservers();\r
 234                 }\r
 235 \r
 236                 /**\r
 237                  * Included for convenient use on {@link Wire}s of length 1.\r
 238                  * \r
 239                  * @return The value of bit 0.\r
 240                  * \r
 241                  * @author Fabian Stemmler\r
 242                  */\r
 243                 public Bit getValue()\r
 244                 {\r
 245                         return Wire.this.getValue();\r
 246                 }\r
 247 \r
 248                 /**\r
 249                  * @param index Index of the requested bit.\r
 250                  * @return The value of the indexed bit.\r
 251                  * \r
 252                  * @author Fabian Stemmler\r
 253                  */\r
 254                 public Bit getValue(int index)\r
 255                 {\r
 256                         return Wire.this.getValue(index);\r
 257                 }\r
 258 \r
 259                 /**\r
 260                  * @param index Index of the requested bit.\r
 261                  * @return The value of the indexed bit.\r
 262                  * \r
 263                  * @author Fabian Stemmler\r
 264                  */\r
 265                 public BitVector getValues()\r
 266                 {\r
 267                         return Wire.this.getValues();\r
 268                 }\r
 269 \r
 270                 /**\r
 271                  * @param start Start of the wanted segment. (inclusive)\r
 272                  * @param end   End of the wanted segment. (exclusive)\r
 273                  * @return The values of the segment of {@link Bit}s indexed.\r
 274                  * \r
 275                  * @author Fabian Stemmler\r
 276                  */\r
 277                 public BitVector getValues(int start, int end)\r
 278                 {\r
 279                         return Wire.this.getValues(start, end);\r
 280                 }\r
 281 \r
 282                 /**\r
 283                  * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 284                  * \r
 285                  * @return <code>true</code> if all bits are either <code>Bit.ONE</code> or <code>Bit.ZERO</code> (they do not all have to have the\r
 286                  *         same value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.\r
 287                  * \r
 288                  * @author Fabian Stemmler\r
 289                  */\r
 290                 public boolean hasNumericValue()\r
 291                 {\r
 292                         return Wire.this.hasNumericValue();\r
 293                 }\r
 294 \r
 295                 /**\r
 296                  * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 297                  * \r
 298                  * @return The unsigned value of the {@link Wire}'s bits, where value 0 corresponds with 2^0, value 1 is 2^1 and so on.\r
 299                  * \r
 300                  * @author Fabian Stemmler\r
 301                  */\r
 302                 public long getUnsignedValue()\r
 303                 {\r
 304                         return Wire.this.getUnsignedValue();\r
 305                 }\r
 306 \r
 307                 /**\r
 308                  * The {@link Wire} is interpreted as a signed integer with n bits.\r
 309                  * \r
 310                  * @return The signed value of the {@link Wire}'s bits, where value 0 corresponds with 2^0, value 1 is 2^1 and so on.\r
 311                  * \r
 312                  * @author Fabian Stemmler\r
 313                  */\r
 314                 public long getSignedValue()\r
 315                 {\r
 316                         return Wire.this.getSignedValue();\r
 317                 }\r
 318 \r
 319                 @Override\r
 320                 public String toString()\r
 321                 {\r
 322                         return Wire.this.toString();\r
 323                 }\r
 324 \r
 325                 public void close()\r
 326                 {\r
 327                         inputs.remove(this);\r
 328                         detachEnd(this);\r
 329                         recalculate();\r
 330                 }\r
 331 \r
 332                 public int length()\r
 333                 {\r
 334                         return length;\r
 335                 }\r
 336 \r
 337                 public Wire getWire()\r
 338                 {\r
 339                         return Wire.this;\r
 340                 }\r
 341 \r
 342                 @Override\r
 343                 public void registerObserver(LogicObserver ob)\r
 344                 {\r
 345                         observers.add(ob);\r
 346                 }\r
 347 \r
 348                 @Override\r
 349                 public void notifyObservers()\r
 350                 {\r
 351                         for (LogicObserver ob : observers)\r
 352                                 ob.update(this);\r
 353                 }\r
 354         }\r
 355 \r
 356         public class ReadWriteEnd extends ReadEnd\r
 357         {\r
 358                 private boolean open;\r
 359                 private BitVector inputValues;\r
 360 \r
 361                 private ReadWriteEnd()\r
 362                 {\r
 363                         super();\r
 364                         open = true;\r
 365                         initValues();\r
 366                         registerInput(this);\r
 367                 }\r
 368 \r
 369                 private void initValues()\r
 370                 {\r
 371                         inputValues = U.toVector(length);\r
 372                 }\r
 373 \r
 374                 /**\r
 375                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.\r
 376                  * \r
 377                  * @param newValues The new values the wires should take on.\r
 378                  * \r
 379                  * @author Fabian Stemmler\r
 380                  */\r
 381                 public void feedSignals(Bit... newValues)\r
 382                 {\r
 383                         feedSignals(BitVector.of(newValues));\r
 384                 }\r
 385 \r
 386                 public void feedSignals(BitVector newValues)\r
 387                 {\r
 388                         if (newValues.length() != length)\r
 389                                 throw new IllegalArgumentException(\r
 390                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));\r
 391                         if (!open)\r
 392                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");\r
 393                         timeline.addEvent(e -> setValues(newValues), travelTime);\r
 394                 }\r
 395 \r
 396                 /**\r
 397                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.\r
 398                  * \r
 399                  * @param bitVector   The new values the wires should take on.\r
 400                  * @param startingBit The first index of the subarray of wires.\r
 401                  * \r
 402                  * @author Fabian Stemmler\r
 403                  */\r
 404                 public void feedSignals(int startingBit, BitVector bitVector)\r
 405                 {\r
 406                         if (!open)\r
 407                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");\r
 408                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);\r
 409                 }\r
 410 \r
 411                 private void setValues(int startingBit, BitVector newValues)\r
 412                 {\r
 413                         // index check covered in equals\r
 414                         if (!inputValues.equalsWithOffset(newValues, startingBit))\r
 415                         {\r
 416                                 Bit[] vals = inputValues.getBits();\r
 417                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());\r
 418                                 inputValues = BitVector.of(vals);\r
 419                                 Wire.this.recalculate();\r
 420                         }\r
 421                 }\r
 422 \r
 423                 private void setValues(BitVector newValues)\r
 424                 {\r
 425                         if (inputValues.equals(newValues))\r
 426                                 return;\r
 427                         inputValues = newValues;\r
 428                         Wire.this.recalculate();\r
 429                 }\r
 430 \r
 431                 /**\r
 432                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.\r
 433                  */\r
 434                 public Bit getInputValue()\r
 435                 {\r
 436                         return getInputValue(0);\r
 437                 }\r
 438 \r
 439                 /**\r
 440                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.\r
 441                  */\r
 442                 public Bit getInputValue(int index)\r
 443                 {\r
 444                         return inputValues.getBit(index);\r
 445                 }\r
 446 \r
 447                 /**\r
 448                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.\r
 449                  */\r
 450                 public BitVector getInputValues()\r
 451                 {\r
 452                         return getInputValues(0, length);\r
 453                 }\r
 454 \r
 455                 public BitVector getInputValues(int start, int end)\r
 456                 {\r
 457                         return inputValues.subVector(start, end);\r
 458                 }\r
 459 \r
 460                 /**\r
 461                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.\r
 462                  */\r
 463                 public void clearSignals()\r
 464                 {\r
 465                         feedSignals(Z.toVector(length));\r
 466                 }\r
 467 \r
 468                 public BitVector wireValuesExcludingMe()\r
 469                 {\r
 470                         BitVectorMutator mutator = BitVectorMutator.empty();\r
 471                         for (ReadWriteEnd wireEnd : inputs)\r
 472                         {\r
 473                                 if (wireEnd == this)\r
 474                                         continue;\r
 475                                 mutator.join(wireEnd.inputValues);\r
 476                         }\r
 477                         return mutator.get();\r
 478                 }\r
 479 \r
 480                 @Override\r
 481                 public String toString()\r
 482                 {\r
 483                         return inputValues.toString();\r
 484                 }\r
 485         }\r
 486 \r
 487         @Override\r
 488         public String toString()\r
 489         {\r
 490                 return String.format("wire 0x%08x value: %s inputs: %s", hashCode(), values, inputs);\r
 491         }\r
 492 \r
 493         public static ReadEnd[] extractEnds(Wire[] w)\r
 494         {\r
 495                 ReadEnd[] inputs = new ReadEnd[w.length];\r
 496                 for (int i = 0; i < w.length; i++)\r
 497                         inputs[i] = w[i].createReadWriteEnd();\r
 498                 return inputs;\r
 499         }\r
 500 }