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

   1 package net.mograsim.logic.core.wires;
   2
   3 import static net.mograsim.logic.core.types.Bit.U;
   4 import static net.mograsim.logic.core.types.Bit.Z;
   5
   6 import java.util.ArrayList;
   7 import java.util.List;
   8
   9 import net.mograsim.logic.core.LogicObservable;
  10 import net.mograsim.logic.core.LogicObserver;
  11 import net.mograsim.logic.core.timeline.Timeline;
  12 import net.mograsim.logic.core.types.Bit;
  13 import net.mograsim.logic.core.types.BitVector;
  14 import net.mograsim.logic.core.types.BitVector.BitVectorMutator;
  15
  16 /**
  17  * Represents an array of wires that can store n bits of information.
  18  *
  19  * @author Fabian Stemmler
  20  *
  21  */
  22 public class Wire
  23 {
  24         public final String name;
  25         private BitVector values;
  26         public final int travelTime;
  27         private List<ReadEnd> attached = new ArrayList<>();
  28         public final int length;
  29         List<ReadWriteEnd> inputs = new ArrayList<>();
  30         Timeline timeline;
  31
  32         public Wire(Timeline timeline, int length, int travelTime)
  33         {
  34                 this(timeline, length, travelTime, null);
  35         }
  36
  37         public Wire(Timeline timeline, int length, int travelTime, String name)
  38         {
  39                 if (length < 1)
  40                         throw new IllegalArgumentException(
  41                                         String.format("Tried to create an array of wires with length %d, but a length of less than 1 makes no sense.", length));
  42                 this.name = name;
  43                 this.timeline = timeline;
  44                 this.length = length;
  45                 this.travelTime = travelTime;
  46                 initValues();
  47         }
  48
  49         private void initValues()
  50         {
  51                 values = U.toVector(length);
  52         }
  53
  54         private void recalculateSingleInput()
  55         {
  56                 setNewValues(inputs.get(0).getInputValues());
  57         }
  58
  59         private void recalculateMultipleInputs()
  60         {
  61                 BitVectorMutator mutator = BitVectorMutator.empty();
  62                 for (ReadWriteEnd wireArrayEnd : inputs)
  63                         mutator.join(wireArrayEnd.getInputValues());
  64                 setNewValues(mutator.get());
  65         }
  66
  67         private void setNewValues(BitVector newValues)
  68         {
  69                 if (values.equals(newValues))
  70                         return;
  71 //              BitVector oldValues = values;
  72                 values = newValues;
  73                 notifyObservers();
  74         }
  75
  76         void recalculate()
  77         {
  78                 switch (inputs.size())
  79                 {
  80                 case 0:
  81                         setNewValues(BitVector.of(Bit.U, length));
  82                         break;
  83                 case 1:
  84                         recalculateSingleInput();
  85                         break;
  86                 default:
  87                         recalculateMultipleInputs();
  88                 }
  89         }
  90
  91         /**
  92          * The {@link Wire} is interpreted as an unsigned integer with n bits.
  93          *
  94          * @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
  95          *         value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
  96          *
  97          * @author Fabian Stemmler
  98          */
  99         public boolean hasNumericValue()
 100         {
 101                 for (Bit b : values)
 102                 {
 103                         if (b != Bit.ZERO && b != Bit.ONE)
 104                                 return false;
 105                 }
 106                 return true;
 107         }
 108
 109         /**
 110          * The {@link Wire} is interpreted as an unsigned integer with n bits.
 111          *
 112          * @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.
 113          *
 114          * @author Fabian Stemmler
 115          */
 116         public long getUnsignedValue()
 117         {
 118                 long val = 0;
 119                 long mask = 1;
 120                 for (Bit bit : values)
 121                 {
 122                         switch (bit)
 123                         {
 124                         default:
 125                         case Z:
 126                         case X:
 127                                 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;
 128                         case ONE:
 129                                 val |= mask;
 130                                 break;
 131                         case ZERO:
 132                         }
 133                         mask = mask << 1;
 134                 }
 135                 return val;
 136         }
 137
 138         /**
 139          * The {@link Wire} is interpreted as a signed integer with n bits.
 140          *
 141          * @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.
 142          *
 143          * @author Fabian Stemmler
 144          */
 145         public long getSignedValue()
 146         {
 147                 long val = getUnsignedValue();
 148                 long mask = 1 << (length - 1);
 149                 if ((mask & val) != 0)
 150                 {
 151                         int shifts = 64 - length;
 152                         return (val << shifts) >> shifts;
 153                 }
 154                 return val;
 155         }
 156
 157         public Bit getValue()
 158         {
 159                 return getValue(0);
 160         }
 161
 162         public Bit getValue(int index)
 163         {
 164                 return values.getBit(index);
 165         }
 166
 167         public BitVector getValues(int start, int end)
 168         {
 169                 return values.subVector(start, end);
 170         }
 171
 172         public BitVector getValues()
 173         {
 174                 return values;
 175         }
 176
 177         /**
 178          * Adds an {@link LogicObserver}, who will be notified when the value of the {@link Wire} is updated.
 179          *
 180          * @param ob The {@link LogicObserver} to be notified of changes.
 181          * @return true if the given {@link LogicObserver} was not already registered, false otherwise
 182          *
 183          * @author Fabian Stemmler
 184          */
 185         void attachEnd(ReadEnd end)
 186         {
 187                 attached.add(end);
 188         }
 189
 190         void detachEnd(ReadEnd end)
 191         {
 192                 attached.remove(end);
 193         }
 194
 195         private void notifyObservers()
 196         {
 197                 attached.forEach(r -> r.update());
 198         }
 199
 200         /**
 201          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.
 202          */
 203         public ReadWriteEnd createReadWriteEnd()
 204         {
 205                 return new ReadWriteEnd();
 206         }
 207
 208         /**
 209          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.
 210          */
 211         public ReadEnd createReadOnlyEnd()
 212         {
 213                 return new ReadEnd();
 214         }
 215
 216         void registerInput(ReadWriteEnd toRegister)
 217         {
 218                 inputs.add(toRegister);
 219         }
 220
 221         /**
 222          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the
 223          * {@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
 224          * and 1 turn into X when they are mixed
 225          *
 226          * @author Fabian Stemmler
 227          */
 228         public class ReadEnd implements LogicObservable
 229         {
 230                 private List<LogicObserver> observers = new ArrayList<>();
 231
 232                 ReadEnd()
 233                 {
 234                         super();
 235                         Wire.this.attachEnd(this);
 236                 }
 237
 238                 public void update()
 239                 {
 240                         notifyObservers();
 241                 }
 242
 243                 /**
 244                  * Included for convenient use on {@link Wire}s of length 1.
 245                  *
 246                  * @return The value of bit 0.
 247                  *
 248                  * @author Fabian Stemmler
 249                  */
 250                 public Bit getValue()
 251                 {
 252                         return Wire.this.getValue();
 253                 }
 254
 255                 /**
 256                  * @param index Index of the requested bit.
 257                  * @return The value of the indexed bit.
 258                  *
 259                  * @author Fabian Stemmler
 260                  */
 261                 public Bit getValue(int index)
 262                 {
 263                         return Wire.this.getValue(index);
 264                 }
 265
 266                 /**
 267                  * @param index Index of the requested bit.
 268                  * @return The value of the indexed bit.
 269                  *
 270                  * @author Fabian Stemmler
 271                  */
 272                 public BitVector getValues()
 273                 {
 274                         return Wire.this.getValues();
 275                 }
 276
 277                 /**
 278                  * @param start Start of the wanted segment. (inclusive)
 279                  * @param end   End of the wanted segment. (exclusive)
 280                  * @return The values of the segment of {@link Bit}s indexed.
 281                  *
 282                  * @author Fabian Stemmler
 283                  */
 284                 public BitVector getValues(int start, int end)
 285                 {
 286                         return Wire.this.getValues(start, end);
 287                 }
 288
 289                 /**
 290                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 291                  *
 292                  * @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
 293                  *         same value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
 294                  *
 295                  * @author Fabian Stemmler
 296                  */
 297                 public boolean hasNumericValue()
 298                 {
 299                         return Wire.this.hasNumericValue();
 300                 }
 301
 302                 /**
 303                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 304                  *
 305                  * @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.
 306                  *
 307                  * @author Fabian Stemmler
 308                  */
 309                 public long getUnsignedValue()
 310                 {
 311                         return Wire.this.getUnsignedValue();
 312                 }
 313
 314                 /**
 315                  * The {@link Wire} is interpreted as a signed integer with n bits.
 316                  *
 317                  * @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.
 318                  *
 319                  * @author Fabian Stemmler
 320                  */
 321                 public long getSignedValue()
 322                 {
 323                         return Wire.this.getSignedValue();
 324                 }
 325
 326                 @Override
 327                 public String toString()
 328                 {
 329                         return Wire.this.toString();
 330                 }
 331
 332                 public void close()
 333                 {
 334                         inputs.remove(this);
 335                         detachEnd(this);
 336                         recalculate();
 337                 }
 338
 339                 public int length()
 340                 {
 341                         return length;
 342                 }
 343
 344                 public Wire getWire()
 345                 {
 346                         return Wire.this;
 347                 }
 348
 349                 @Override
 350                 public void registerObserver(LogicObserver ob)
 351                 {
 352                         observers.add(ob);
 353                 }
 354
 355                 @Override
 356                 public void deregisterObserver(LogicObserver ob)
 357                 {
 358                         observers.remove(ob);
 359                 }
 360
 361                 @Override
 362                 public void notifyObservers()
 363                 {
 364                         observers.forEach(ob -> ob.update(this));
 365                 }
 366         }
 367
 368         public class ReadWriteEnd extends ReadEnd
 369         {
 370                 private boolean open, isWriting;
 371                 private BitVector inputValues;
 372
 373                 ReadWriteEnd()
 374                 {
 375                         super();
 376                         open = true;
 377                         isWriting = true;
 378                         initValues();
 379                         registerInput(this);
 380                 }
 381
 382                 private void initValues()
 383                 {
 384                         inputValues = U.toVector(length);
 385                 }
 386
 387                 /**
 388                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.
 389                  *
 390                  * @param newValues The new values the wires should take on.
 391                  *
 392                  * @author Fabian Stemmler
 393                  */
 394                 public void feedSignals(Bit... newValues)
 395                 {
 396                         feedSignals(BitVector.of(newValues));
 397                 }
 398
 399                 public void feedSignals(BitVector newValues)
 400                 {
 401                         if (newValues.length() != length)
 402                                 throw new IllegalArgumentException(
 403                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));
 404                         if (!open)
 405                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 406                         timeline.addEvent(e -> setValues(newValues), travelTime);
 407                 }
 408
 409                 /**
 410                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.
 411                  *
 412                  * @param bitVector   The new values the wires should take on.
 413                  * @param startingBit The first index of the subarray of wires.
 414                  *
 415                  * @author Fabian Stemmler
 416                  */
 417                 public void feedSignals(int startingBit, BitVector bitVector)
 418                 {
 419                         if (!open)
 420                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 421                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);
 422                 }
 423
 424                 /**
 425                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via
 426                  * feedValues(...) with a delay.
 427                  */
 428                 void setValues(int startingBit, BitVector newValues)
 429                 {
 430                         // index check covered in equals
 431                         if (!inputValues.equalsWithOffset(newValues, startingBit))
 432                         {
 433                                 Bit[] vals = inputValues.getBits();
 434                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());
 435                                 inputValues = BitVector.of(vals);
 436                                 Wire.this.recalculate();
 437                         }
 438                 }
 439
 440                 /**
 441                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via
 442                  * feedValues(...) with a delay.
 443                  */
 444                 void setValues(BitVector newValues)
 445                 {
 446                         if (inputValues.equals(newValues))
 447                                 return;
 448                         inputValues = newValues;
 449                         Wire.this.recalculate();
 450                 }
 451
 452                 /**
 453                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 454                  */
 455                 public Bit getInputValue()
 456                 {
 457                         return getInputValue(0);
 458                 }
 459
 460                 /**
 461                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.
 462                  */
 463                 public Bit getInputValue(int index)
 464                 {
 465                         return inputValues.getBit(index);
 466                 }
 467
 468                 /**
 469                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 470                  */
 471                 public BitVector getInputValues()
 472                 {
 473                         return getInputValues(0, length);
 474                 }
 475
 476                 public BitVector getInputValues(int start, int end)
 477                 {
 478                         return inputValues.subVector(start, end);
 479                 }
 480
 481                 /**
 482                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.
 483                  */
 484                 public void clearSignals()
 485                 {
 486                         feedSignals(Z.toVector(length));
 487                 }
 488
 489                 public BitVector wireValuesExcludingMe()
 490                 {
 491                         BitVectorMutator mutator = BitVectorMutator.empty();
 492                         for (ReadWriteEnd wireEnd : inputs)
 493                         {
 494                                 if (wireEnd == this)
 495                                         continue;
 496                                 mutator.join(wireEnd.inputValues);
 497                         }
 498                         return mutator.get();
 499                 }
 500
 501                 @Override
 502                 public String toString()
 503                 {
 504                         return inputValues.toString();
 505                 }
 506
 507                 @Override
 508                 public void close()
 509                 {
 510                         super.close();
 511                         open = false;
 512                 }
 513
 514                 void setWriting(boolean isWriting)
 515                 {
 516                         if (this.isWriting != isWriting)
 517                         {
 518                                 this.isWriting = isWriting;
 519                                 if (isWriting)
 520                                         inputs.add(this);
 521                                 else
 522                                         inputs.remove(this);
 523                                 Wire.this.recalculate();
 524                         }
 525                 }
 526
 527                 boolean isWriting()
 528                 {
 529                         return isWriting;
 530                 }
 531         }
 532
 533         @Override
 534         public String toString()
 535         {
 536                 String name = this.name == null ? String.format("0x%08x", hashCode()) : this.name;
 537                 return String.format("wire %s value: %s inputs: %s", name, values, inputs);
 538         }
 539
 540         public static ReadEnd[] extractEnds(Wire[] w)
 541         {
 542                 ReadEnd[] inputs = new ReadEnd[w.length];
 543                 for (int i = 0; i < w.length; i++)
 544                         inputs[i] = w[i].createReadWriteEnd();
 545                 return inputs;
 546         }
 547
 548         // TODO Fix ReadWriteEnd feeding signals to entire Wire (Z) instead of only selected Bits
 549         /**
 550          * Fuses the selected bits of two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning:
 551          * The bits are permanently fused together.
 552          *
 553          * @param a      The {@link Wire} to be (partially) fused with b
 554          * @param b      The {@link Wire} to be (partially) fused with a
 555          * @param fromA  The first bit of {@link Wire} a to be fused
 556          * @param fromB  The first bit of {@link Wire} b to be fused
 557          * @param length The amount of bits to fuse
 558          */
 559         public static void fuse(Wire a, Wire b, int fromA, int fromB, int length)
 560         {
 561                 ReadWriteEnd rA = a.createReadWriteEnd(), rB = b.createReadWriteEnd();
 562                 rA.setWriting(false);
 563                 rB.setWriting(false);
 564                 rA.setValues(BitVector.of(Bit.Z, a.length));
 565                 rB.setValues(BitVector.of(Bit.Z, b.length));
 566                 Fusion aF = new Fusion(rB, fromA, fromB, length), bF = new Fusion(rA, fromB, fromA, length);
 567                 rA.registerObserver(aF);
 568                 rB.registerObserver(bF);
 569                 aF.update(rA);
 570                 bF.update(rB);
 571         }
 572
 573         /**
 574          *
 575          * Fuses two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning: The bits are
 576          * permanently fused together.
 577          *
 578          * @param a The {@link Wire} to be fused with b
 579          * @param b The {@link Wire} to be fused with a
 580          */
 581         public static void fuse(Wire a, Wire b)
 582         {
 583                 fuse(a, b, 0, 0, a.length);
 584         }
 585
 586         private static class Fusion implements LogicObserver
 587         {
 588                 private ReadWriteEnd target;
 589                 int fromSource, fromTarget, length;
 590
 591                 public Fusion(ReadWriteEnd target, int fromSource, int fromTarget, int length)
 592                 {
 593                         this.target = target;
 594                         this.fromSource = fromSource;
 595                         this.fromTarget = fromTarget;
 596                         this.length = length;
 597                 }
 598
 599                 @Override
 600                 public void update(LogicObservable initiator)
 601                 {
 602                         ReadWriteEnd source = (ReadWriteEnd) initiator;
 603                         if (source.getWire().inputs.size() - (source.isWriting() ? 1 : 0) == 0)
 604                                 target.setWriting(false);
 605                         else
 606                         {
 607                                 target.setWriting(true);
 608                                 BitVector targetInput = source.wireValuesExcludingMe().subVector(fromSource, fromSource + length);
 609                                 target.setValues(fromTarget, targetInput);
 610                         }
 611                 }
 612         }
 613 }