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         public final String name;\r
  25         private BitVector values;\r
  26         public final int travelTime;\r
  27         private List<ReadEnd> attached = new ArrayList<>();\r
  28         public final int length;\r
  29         List<ReadWriteEnd> inputs = new ArrayList<>();\r
  30         Timeline timeline;\r
  31 \r
  32         public Wire(Timeline timeline, int length, int travelTime)\r
  33         {\r
  34                 this(timeline, length, travelTime, null);\r
  35         }\r
  36 \r
  37         public Wire(Timeline timeline, int length, int travelTime, String name)\r
  38         {\r
  39                 if (length < 1)\r
  40                         throw new IllegalArgumentException(\r
  41                                         String.format("Tried to create an array of wires with length %d, but a length of less than 1 makes no sense.", length));\r
  42                 this.name = name;\r
  43                 this.timeline = timeline;\r
  44                 this.length = length;\r
  45                 this.travelTime = travelTime;\r
  46                 initValues();\r
  47         }\r
  48 \r
  49         private void initValues()\r
  50         {\r
  51                 values = U.toVector(length);\r
  52         }\r
  53 \r
  54         private void setNewValues(BitVector newValues)\r
  55         {\r
  56                 if (values.equals(newValues))\r
  57                         return;\r
  58 //              BitVector oldValues = values;\r
  59                 values = newValues;\r
  60                 notifyObservers();\r
  61         }\r
  62 \r
  63         void recalculate()\r
  64         {\r
  65                 if (inputs.size() == 0)\r
  66                         setNewValues(BitVector.of(Bit.U, length));\r
  67                 else\r
  68                 {\r
  69                         BitVectorMutator mutator = BitVectorMutator.empty();\r
  70                         for (ReadWriteEnd wireArrayEnd : inputs)\r
  71                                 mutator.join(wireArrayEnd.getInputValues());\r
  72                         setNewValues(mutator.toBitVector());\r
  73                 }\r
  74         }\r
  75 \r
  76         /**\r
  77          * Forces a Wire to take on specific values. If the new values differ from the old ones, the observers of the Wire will be notified.\r
  78          * WARNING! Use this with care! The preferred way of writing the values is ReadWriteEnd.feedSignals(BitVector)\r
  79          * \r
  80          * @param values The values the <code>Wire</code> will have immediately after this method is called\r
  81          */\r
  82         public void forceValues(BitVector values)\r
  83         {\r
  84                 setNewValues(values);\r
  85         }\r
  86 \r
  87         /**\r
  88          * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
  89          * \r
  90          * @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
  91          *         value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.\r
  92          * \r
  93          * @author Fabian Stemmler\r
  94          */\r
  95         public boolean hasNumericValue()\r
  96         {\r
  97                 for (Bit b : values)\r
  98                 {\r
  99                         if (b != Bit.ZERO && b != Bit.ONE)\r
 100                                 return false;\r
 101                 }\r
 102                 return true;\r
 103         }\r
 104 \r
 105         /**\r
 106          * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 107          * \r
 108          * @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
 109          * \r
 110          * @author Fabian Stemmler\r
 111          */\r
 112         public long getUnsignedValue()\r
 113         {\r
 114                 long val = 0;\r
 115                 long mask = 1;\r
 116                 for (Bit bit : values)\r
 117                 {\r
 118                         switch (bit)\r
 119                         {\r
 120                         default:\r
 121                         case Z:\r
 122                         case X:\r
 123                                 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;\r
 124                         case ONE:\r
 125                                 val |= mask;\r
 126                                 break;\r
 127                         case ZERO:\r
 128                         }\r
 129                         mask = mask << 1;\r
 130                 }\r
 131                 return val;\r
 132         }\r
 133 \r
 134         /**\r
 135          * The {@link Wire} is interpreted as a signed integer with n bits.\r
 136          * \r
 137          * @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
 138          * \r
 139          * @author Fabian Stemmler\r
 140          */\r
 141         public long getSignedValue()\r
 142         {\r
 143                 long val = getUnsignedValue();\r
 144                 long mask = 1 << (length - 1);\r
 145                 if ((mask & val) != 0)\r
 146                 {\r
 147                         int shifts = 64 - length;\r
 148                         return (val << shifts) >> shifts;\r
 149                 }\r
 150                 return val;\r
 151         }\r
 152 \r
 153         /**\r
 154          * Returns the least significant bit (LSB)\r
 155          */\r
 156         public Bit getValue()\r
 157         {\r
 158                 return getValue(0);\r
 159         }\r
 160 \r
 161         /**\r
 162          * Returns the least significant bit (LSB) of the given index\r
 163          */\r
 164         public Bit getValue(int index)\r
 165         {\r
 166                 return values.getLSBit(index);\r
 167         }\r
 168 \r
 169         public BitVector getValues(int start, int end)\r
 170         {\r
 171                 return values.subVector(start, end);\r
 172         }\r
 173 \r
 174         public BitVector getValues()\r
 175         {\r
 176                 return values;\r
 177         }\r
 178 \r
 179         /**\r
 180          * Adds an {@link LogicObserver}, who will be notified when the value of the {@link Wire} is updated.\r
 181          * \r
 182          * @param ob The {@link LogicObserver} to be notified of changes.\r
 183          * @return true if the given {@link LogicObserver} was not already registered, false otherwise\r
 184          * \r
 185          * @author Fabian Stemmler\r
 186          */\r
 187         void attachEnd(ReadEnd end)\r
 188         {\r
 189                 attached.add(end);\r
 190         }\r
 191 \r
 192         void detachEnd(ReadEnd end)\r
 193         {\r
 194                 attached.remove(end);\r
 195         }\r
 196 \r
 197         private void notifyObservers()\r
 198         {\r
 199                 attached.forEach(r -> r.update());\r
 200         }\r
 201 \r
 202         /**\r
 203          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.\r
 204          */\r
 205         public ReadWriteEnd createReadWriteEnd()\r
 206         {\r
 207                 return new ReadWriteEnd();\r
 208         }\r
 209 \r
 210         /**\r
 211          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.\r
 212          */\r
 213         public ReadEnd createReadOnlyEnd()\r
 214         {\r
 215                 return new ReadEnd();\r
 216         }\r
 217 \r
 218         void registerInput(ReadWriteEnd toRegister)\r
 219         {\r
 220                 inputs.add(toRegister);\r
 221         }\r
 222 \r
 223         /**\r
 224          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the\r
 225          * {@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
 226          * and 1 turn into X when they are mixed\r
 227          * \r
 228          * @author Fabian Stemmler\r
 229          */\r
 230         public class ReadEnd implements LogicObservable\r
 231         {\r
 232                 private List<LogicObserver> observers = new ArrayList<>();\r
 233 \r
 234                 ReadEnd()\r
 235                 {\r
 236                         super();\r
 237                         Wire.this.attachEnd(this);\r
 238                 }\r
 239 \r
 240                 public void update()\r
 241                 {\r
 242                         notifyObservers();\r
 243                 }\r
 244 \r
 245                 /**\r
 246                  * Included for convenient use on {@link Wire}s of length 1.\r
 247                  * \r
 248                  * @return The value of bit 0.\r
 249                  * \r
 250                  * @author Fabian Stemmler\r
 251                  */\r
 252                 public Bit getValue()\r
 253                 {\r
 254                         return Wire.this.getValue();\r
 255                 }\r
 256 \r
 257                 /**\r
 258                  * @param index Index of the requested bit.\r
 259                  * @return The value of the indexed bit.\r
 260                  * \r
 261                  * @author Fabian Stemmler\r
 262                  */\r
 263                 public Bit getValue(int index)\r
 264                 {\r
 265                         return Wire.this.getValue(index);\r
 266                 }\r
 267 \r
 268                 public BitVector getValues()\r
 269                 {\r
 270                         return Wire.this.getValues();\r
 271                 }\r
 272 \r
 273                 /**\r
 274                  * @param start Start of the wanted segment. (inclusive)\r
 275                  * @param end   End of the wanted segment. (exclusive)\r
 276                  * @return The values of the segment of {@link Bit}s indexed.\r
 277                  * \r
 278                  * @author Fabian Stemmler\r
 279                  */\r
 280                 public BitVector getValues(int start, int end)\r
 281                 {\r
 282                         return Wire.this.getValues(start, end);\r
 283                 }\r
 284 \r
 285                 /**\r
 286                  * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 287                  * \r
 288                  * @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
 289                  *         same value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.\r
 290                  * \r
 291                  * @author Fabian Stemmler\r
 292                  */\r
 293                 public boolean hasNumericValue()\r
 294                 {\r
 295                         return Wire.this.hasNumericValue();\r
 296                 }\r
 297 \r
 298                 /**\r
 299                  * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 300                  * \r
 301                  * @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
 302                  * \r
 303                  * @author Fabian Stemmler\r
 304                  */\r
 305                 public long getUnsignedValue()\r
 306                 {\r
 307                         return Wire.this.getUnsignedValue();\r
 308                 }\r
 309 \r
 310                 /**\r
 311                  * The {@link Wire} is interpreted as a signed integer with n bits.\r
 312                  * \r
 313                  * @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
 314                  * \r
 315                  * @author Fabian Stemmler\r
 316                  */\r
 317                 public long getSignedValue()\r
 318                 {\r
 319                         return Wire.this.getSignedValue();\r
 320                 }\r
 321 \r
 322                 @Override\r
 323                 public String toString()\r
 324                 {\r
 325                         return Wire.this.toString();\r
 326                 }\r
 327 \r
 328                 public void close()\r
 329                 {\r
 330                         inputs.remove(this);\r
 331                         detachEnd(this);\r
 332                         recalculate();\r
 333                 }\r
 334 \r
 335                 public int length()\r
 336                 {\r
 337                         return length;\r
 338                 }\r
 339 \r
 340                 public Wire getWire()\r
 341                 {\r
 342                         return Wire.this;\r
 343                 }\r
 344 \r
 345                 @Override\r
 346                 public void registerObserver(LogicObserver ob)\r
 347                 {\r
 348                         observers.add(ob);\r
 349                 }\r
 350 \r
 351                 @Override\r
 352                 public void deregisterObserver(LogicObserver ob)\r
 353                 {\r
 354                         observers.remove(ob);\r
 355                 }\r
 356 \r
 357                 @Override\r
 358                 public void notifyObservers()\r
 359                 {\r
 360                         observers.forEach(ob -> ob.update(this));\r
 361                 }\r
 362         }\r
 363 \r
 364         public class ReadWriteEnd extends ReadEnd\r
 365         {\r
 366                 private boolean open, isWriting;\r
 367                 private BitVector inputValues;\r
 368 \r
 369                 ReadWriteEnd()\r
 370                 {\r
 371                         super();\r
 372                         open = true;\r
 373                         isWriting = true;\r
 374                         initValues();\r
 375                         registerInput(this);\r
 376                 }\r
 377 \r
 378                 private void initValues()\r
 379                 {\r
 380                         inputValues = U.toVector(length);\r
 381                 }\r
 382 \r
 383                 /**\r
 384                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.\r
 385                  * \r
 386                  * @param newValues The new values the wires should take on.\r
 387                  * \r
 388                  * @author Fabian Stemmler\r
 389                  */\r
 390                 public void feedSignals(Bit... newValues)\r
 391                 {\r
 392                         feedSignals(BitVector.of(newValues));\r
 393                 }\r
 394 \r
 395                 public void feedSignals(BitVector newValues)\r
 396                 {\r
 397                         if (newValues.length() != length)\r
 398                                 throw new IllegalArgumentException(\r
 399                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));\r
 400                         if (!open)\r
 401                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");\r
 402                         timeline.addEvent(e -> setValues(newValues), travelTime);\r
 403                 }\r
 404 \r
 405                 /**\r
 406                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.\r
 407                  * \r
 408                  * @param bitVector   The new values the wires should take on.\r
 409                  * @param startingBit The first index of the subarray of wires.\r
 410                  * \r
 411                  * @author Fabian Stemmler\r
 412                  */\r
 413                 public void feedSignals(int startingBit, BitVector bitVector)\r
 414                 {\r
 415                         if (!open)\r
 416                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");\r
 417                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);\r
 418                 }\r
 419 \r
 420                 /**\r
 421                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via\r
 422                  * feedValues(...) with a delay.\r
 423                  */\r
 424                 void setValues(int startingBit, BitVector newValues)\r
 425                 {\r
 426                         // index check covered in equals\r
 427                         if (!inputValues.equalsWithOffset(newValues, startingBit))\r
 428                         {\r
 429                                 Bit[] vals = inputValues.getBits();\r
 430                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());\r
 431                                 inputValues = BitVector.of(vals);\r
 432                                 Wire.this.recalculate();\r
 433                         }\r
 434                 }\r
 435 \r
 436                 /**\r
 437                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via\r
 438                  * feedValues(...) with a delay.\r
 439                  */\r
 440                 void setValues(BitVector newValues)\r
 441                 {\r
 442                         if (inputValues.equals(newValues))\r
 443                                 return;\r
 444                         inputValues = newValues;\r
 445                         Wire.this.recalculate();\r
 446                 }\r
 447 \r
 448                 /**\r
 449                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.Returns the least\r
 450                  *         significant bit (LSB)\r
 451                  */\r
 452                 public Bit getInputValue()\r
 453                 {\r
 454                         return getInputValue(0);\r
 455                 }\r
 456 \r
 457                 /**\r
 458                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.\r
 459                  *         Returns the least significant bit (LSB)\r
 460                  * \r
 461                  */\r
 462                 public Bit getInputValue(int index)\r
 463                 {\r
 464                         return inputValues.getLSBit(index);\r
 465                 }\r
 466 \r
 467                 /**\r
 468                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.\r
 469                  */\r
 470                 public BitVector getInputValues()\r
 471                 {\r
 472                         return inputValues;\r
 473                 }\r
 474 \r
 475                 public BitVector getInputValues(int start, int end)\r
 476                 {\r
 477                         return inputValues.subVector(start, end);\r
 478                 }\r
 479 \r
 480                 /**\r
 481                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.\r
 482                  */\r
 483                 public void clearSignals()\r
 484                 {\r
 485                         feedSignals(Z.toVector(length));\r
 486                 }\r
 487 \r
 488                 public BitVector wireValuesExcludingMe()\r
 489                 {\r
 490                         BitVectorMutator mutator = BitVectorMutator.empty();\r
 491                         for (ReadWriteEnd wireEnd : inputs)\r
 492                         {\r
 493                                 if (wireEnd == this)\r
 494                                         continue;\r
 495                                 mutator.join(wireEnd.inputValues);\r
 496                         }\r
 497                         return mutator.toBitVector();\r
 498                 }\r
 499 \r
 500                 @Override\r
 501                 public String toString()\r
 502                 {\r
 503                         return inputValues.toString();\r
 504                 }\r
 505 \r
 506                 @Override\r
 507                 public void close()\r
 508                 {\r
 509                         super.close();\r
 510                         open = false;\r
 511                 }\r
 512 \r
 513                 void setWriting(boolean isWriting)\r
 514                 {\r
 515                         if (this.isWriting != isWriting)\r
 516                         {\r
 517                                 this.isWriting = isWriting;\r
 518                                 if (isWriting)\r
 519                                         inputs.add(this);\r
 520                                 else\r
 521                                         inputs.remove(this);\r
 522                                 Wire.this.recalculate();\r
 523                         }\r
 524                 }\r
 525 \r
 526                 boolean isWriting()\r
 527                 {\r
 528                         return isWriting;\r
 529                 }\r
 530         }\r
 531 \r
 532         @Override\r
 533         public String toString()\r
 534         {\r
 535                 String name = this.name == null ? String.format("0x%08x", hashCode()) : this.name;\r
 536                 return String.format("wire %s value: %s inputs: %s", name, values, inputs);\r
 537         }\r
 538 \r
 539         public static ReadEnd[] extractEnds(Wire[] w)\r
 540         {\r
 541                 ReadEnd[] inputs = new ReadEnd[w.length];\r
 542                 for (int i = 0; i < w.length; i++)\r
 543                         inputs[i] = w[i].createReadWriteEnd();\r
 544                 return inputs;\r
 545         }\r
 546 \r
 547         // TODO Fix ReadWriteEnd feeding signals to entire Wire (Z) instead of only selected Bits\r
 548         /**\r
 549          * Fuses the selected bits of two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning:\r
 550          * The bits are permanently fused together.\r
 551          * \r
 552          * @param a      The {@link Wire} to be (partially) fused with b\r
 553          * @param b      The {@link Wire} to be (partially) fused with a\r
 554          * @param fromA  The first bit of {@link Wire} a to be fused\r
 555          * @param fromB  The first bit of {@link Wire} b to be fused\r
 556          * @param length The amount of bits to fuse\r
 557          */\r
 558         public static void fuse(Wire a, Wire b, int fromA, int fromB, int length)\r
 559         {\r
 560                 ReadWriteEnd rA = a.createReadWriteEnd(), rB = b.createReadWriteEnd();\r
 561                 rA.setWriting(false);\r
 562                 rB.setWriting(false);\r
 563                 rA.setValues(BitVector.of(Bit.Z, a.length));\r
 564                 rB.setValues(BitVector.of(Bit.Z, b.length));\r
 565                 Fusion aF = new Fusion(rB, fromA, fromB, length), bF = new Fusion(rA, fromB, fromA, length);\r
 566                 rA.registerObserver(aF);\r
 567                 rB.registerObserver(bF);\r
 568                 aF.update(rA);\r
 569                 bF.update(rB);\r
 570         }\r
 571 \r
 572         /**\r
 573          * \r
 574          * Fuses two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning: The bits are\r
 575          * permanently fused together.\r
 576          * \r
 577          * @param a The {@link Wire} to be fused with b\r
 578          * @param b The {@link Wire} to be fused with a\r
 579          */\r
 580         public static void fuse(Wire a, Wire b)\r
 581         {\r
 582                 fuse(a, b, 0, 0, a.length);\r
 583         }\r
 584 \r
 585         private static class Fusion implements LogicObserver\r
 586         {\r
 587                 private ReadWriteEnd target;\r
 588                 int fromSource, fromTarget, length;\r
 589 \r
 590                 public Fusion(ReadWriteEnd target, int fromSource, int fromTarget, int length)\r
 591                 {\r
 592                         this.target = target;\r
 593                         this.fromSource = fromSource;\r
 594                         this.fromTarget = fromTarget;\r
 595                         this.length = length;\r
 596                 }\r
 597 \r
 598                 @Override\r
 599                 public void update(LogicObservable initiator)\r
 600                 {\r
 601                         ReadWriteEnd source = (ReadWriteEnd) initiator;\r
 602                         if (source.getWire().inputs.size() - (source.isWriting() ? 1 : 0) == 0)\r
 603                                 target.setWriting(false);\r
 604                         else\r
 605                         {\r
 606                                 target.setWriting(true);\r
 607                                 BitVector targetInput = source.wireValuesExcludingMe().subVector(fromSource, fromSource + length);\r
 608                                 target.setValues(fromTarget, targetInput);\r
 609                         }\r
 610                 }\r
 611         }\r
 612 }