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 setNewValues(BitVector newValues)
  55         {
  56                 if (values.equals(newValues))
  57                         return;
  58 //              BitVector oldValues = values;
  59                 values = newValues;
  60                 notifyObservers();
  61         }
  62
  63         void recalculate()
  64         {
  65                 if (inputs.size() == 0)
  66                         setNewValues(BitVector.of(Bit.U, length));
  67                 else
  68                 {
  69                         BitVectorMutator mutator = BitVectorMutator.empty();
  70                         for (ReadWriteEnd wireArrayEnd : inputs)
  71                                 mutator.join(wireArrayEnd.getInputValues());
  72                         setNewValues(mutator.toBitVector());
  73                 }
  74         }
  75
  76         /**
  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.
  78          * WARNING! Use this with care! The preferred way of writing the values is ReadWriteEnd.feedSignals(BitVector)
  79          *
  80          * @param values The values the <code>Wire</code> will have immediately after this method is called
  81          */
  82         public void forceValues(BitVector values)
  83         {
  84                 setNewValues(values);
  85         }
  86
  87         /**
  88          * The {@link Wire} is interpreted as an unsigned integer with n bits.
  89          *
  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
  91          *         value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
  92          *
  93          * @author Fabian Stemmler
  94          */
  95         public boolean hasNumericValue()
  96         {
  97                 for (Bit b : values)
  98                 {
  99                         if (b != Bit.ZERO && b != Bit.ONE)
 100                                 return false;
 101                 }
 102                 return true;
 103         }
 104
 105         /**
 106          * The {@link Wire} is interpreted as an unsigned integer with n bits.
 107          *
 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.
 109          *
 110          * @author Fabian Stemmler
 111          */
 112         public long getUnsignedValue()
 113         {
 114                 long val = 0;
 115                 long mask = 1;
 116                 for (Bit bit : values)
 117                 {
 118                         switch (bit)
 119                         {
 120                         default:
 121                         case Z:
 122                         case X:
 123                                 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;
 124                         case ONE:
 125                                 val |= mask;
 126                                 break;
 127                         case ZERO:
 128                         }
 129                         mask = mask << 1;
 130                 }
 131                 return val;
 132         }
 133
 134         /**
 135          * The {@link Wire} is interpreted as a signed integer with n bits.
 136          *
 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.
 138          *
 139          * @author Fabian Stemmler
 140          */
 141         public long getSignedValue()
 142         {
 143                 long val = getUnsignedValue();
 144                 long mask = 1 << (length - 1);
 145                 if ((mask & val) != 0)
 146                 {
 147                         int shifts = 64 - length;
 148                         return (val << shifts) >> shifts;
 149                 }
 150                 return val;
 151         }
 152
 153         /**
 154          * Returns the least significant bit (LSB)
 155          */
 156         public Bit getValue()
 157         {
 158                 return getValue(0);
 159         }
 160
 161         /**
 162          * Returns the least significant bit (LSB) of the given index
 163          */
 164         public Bit getValue(int index)
 165         {
 166                 return values.getLSBit(index);
 167         }
 168
 169         public BitVector getValues(int start, int end)
 170         {
 171                 return values.subVector(start, end);
 172         }
 173
 174         public BitVector getValues()
 175         {
 176                 return values;
 177         }
 178
 179         /**
 180          * Adds an {@link LogicObserver}, who will be notified when the value of the {@link Wire} is updated.
 181          *
 182          * @param ob The {@link LogicObserver} to be notified of changes.
 183          * @return true if the given {@link LogicObserver} was not already registered, false otherwise
 184          *
 185          * @author Fabian Stemmler
 186          */
 187         void attachEnd(ReadEnd end)
 188         {
 189                 attached.add(end);
 190         }
 191
 192         void detachEnd(ReadEnd end)
 193         {
 194                 attached.remove(end);
 195         }
 196
 197         private void notifyObservers()
 198         {
 199                 attached.forEach(r -> r.update());
 200         }
 201
 202         /**
 203          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.
 204          */
 205         public ReadWriteEnd createReadWriteEnd()
 206         {
 207                 return new ReadWriteEnd();
 208         }
 209
 210         /**
 211          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.
 212          */
 213         public ReadEnd createReadOnlyEnd()
 214         {
 215                 return new ReadEnd();
 216         }
 217
 218         void registerInput(ReadWriteEnd toRegister)
 219         {
 220                 inputs.add(toRegister);
 221         }
 222
 223         /**
 224          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the
 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
 226          * and 1 turn into X when they are mixed
 227          *
 228          * @author Fabian Stemmler
 229          */
 230         public class ReadEnd implements LogicObservable
 231         {
 232                 private List<LogicObserver> observers = new ArrayList<>();
 233
 234                 ReadEnd()
 235                 {
 236                         super();
 237                         Wire.this.attachEnd(this);
 238                 }
 239
 240                 public void update()
 241                 {
 242                         notifyObservers();
 243                 }
 244
 245                 /**
 246                  * Included for convenient use on {@link Wire}s of length 1.
 247                  *
 248                  * @return The value of bit 0.
 249                  *
 250                  * @author Fabian Stemmler
 251                  */
 252                 public Bit getValue()
 253                 {
 254                         return Wire.this.getValue();
 255                 }
 256
 257                 /**
 258                  * @param index Index of the requested bit.
 259                  * @return The value of the indexed bit.
 260                  *
 261                  * @author Fabian Stemmler
 262                  */
 263                 public Bit getValue(int index)
 264                 {
 265                         return Wire.this.getValue(index);
 266                 }
 267
 268                 /**
 269                  * @param index Index of the requested bit.
 270                  * @return The value of the indexed bit.
 271                  *
 272                  * @author Fabian Stemmler
 273                  */
 274                 public BitVector getValues()
 275                 {
 276                         return Wire.this.getValues();
 277                 }
 278
 279                 /**
 280                  * @param start Start of the wanted segment. (inclusive)
 281                  * @param end   End of the wanted segment. (exclusive)
 282                  * @return The values of the segment of {@link Bit}s indexed.
 283                  *
 284                  * @author Fabian Stemmler
 285                  */
 286                 public BitVector getValues(int start, int end)
 287                 {
 288                         return Wire.this.getValues(start, end);
 289                 }
 290
 291                 /**
 292                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 293                  *
 294                  * @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
 295                  *         same value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
 296                  *
 297                  * @author Fabian Stemmler
 298                  */
 299                 public boolean hasNumericValue()
 300                 {
 301                         return Wire.this.hasNumericValue();
 302                 }
 303
 304                 /**
 305                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 306                  *
 307                  * @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.
 308                  *
 309                  * @author Fabian Stemmler
 310                  */
 311                 public long getUnsignedValue()
 312                 {
 313                         return Wire.this.getUnsignedValue();
 314                 }
 315
 316                 /**
 317                  * The {@link Wire} is interpreted as a signed integer with n bits.
 318                  *
 319                  * @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.
 320                  *
 321                  * @author Fabian Stemmler
 322                  */
 323                 public long getSignedValue()
 324                 {
 325                         return Wire.this.getSignedValue();
 326                 }
 327
 328                 @Override
 329                 public String toString()
 330                 {
 331                         return Wire.this.toString();
 332                 }
 333
 334                 public void close()
 335                 {
 336                         inputs.remove(this);
 337                         detachEnd(this);
 338                         recalculate();
 339                 }
 340
 341                 public int length()
 342                 {
 343                         return length;
 344                 }
 345
 346                 public Wire getWire()
 347                 {
 348                         return Wire.this;
 349                 }
 350
 351                 @Override
 352                 public void registerObserver(LogicObserver ob)
 353                 {
 354                         observers.add(ob);
 355                 }
 356
 357                 @Override
 358                 public void deregisterObserver(LogicObserver ob)
 359                 {
 360                         observers.remove(ob);
 361                 }
 362
 363                 @Override
 364                 public void notifyObservers()
 365                 {
 366                         observers.forEach(ob -> ob.update(this));
 367                 }
 368         }
 369
 370         public class ReadWriteEnd extends ReadEnd
 371         {
 372                 private boolean open, isWriting;
 373                 private BitVector inputValues;
 374
 375                 ReadWriteEnd()
 376                 {
 377                         super();
 378                         open = true;
 379                         isWriting = true;
 380                         initValues();
 381                         registerInput(this);
 382                 }
 383
 384                 private void initValues()
 385                 {
 386                         inputValues = U.toVector(length);
 387                 }
 388
 389                 /**
 390                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.
 391                  *
 392                  * @param newValues The new values the wires should take on.
 393                  *
 394                  * @author Fabian Stemmler
 395                  */
 396                 public void feedSignals(Bit... newValues)
 397                 {
 398                         feedSignals(BitVector.of(newValues));
 399                 }
 400
 401                 public void feedSignals(BitVector newValues)
 402                 {
 403                         if (newValues.length() != length)
 404                                 throw new IllegalArgumentException(
 405                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));
 406                         if (!open)
 407                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 408                         timeline.addEvent(e -> setValues(newValues), travelTime);
 409                 }
 410
 411                 /**
 412                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.
 413                  *
 414                  * @param bitVector   The new values the wires should take on.
 415                  * @param startingBit The first index of the subarray of wires.
 416                  *
 417                  * @author Fabian Stemmler
 418                  */
 419                 public void feedSignals(int startingBit, BitVector bitVector)
 420                 {
 421                         if (!open)
 422                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 423                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);
 424                 }
 425
 426                 /**
 427                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via
 428                  * feedValues(...) with a delay.
 429                  */
 430                 void setValues(int startingBit, BitVector newValues)
 431                 {
 432                         // index check covered in equals
 433                         if (!inputValues.equalsWithOffset(newValues, startingBit))
 434                         {
 435                                 Bit[] vals = inputValues.getBits();
 436                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());
 437                                 inputValues = BitVector.of(vals);
 438                                 Wire.this.recalculate();
 439                         }
 440                 }
 441
 442                 /**
 443                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via
 444                  * feedValues(...) with a delay.
 445                  */
 446                 void setValues(BitVector newValues)
 447                 {
 448                         if (inputValues.equals(newValues))
 449                                 return;
 450                         inputValues = newValues;
 451                         Wire.this.recalculate();
 452                 }
 453
 454                 /**
 455                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.Returns the least
 456                  *         significant bit (LSB)
 457                  */
 458                 public Bit getInputValue()
 459                 {
 460                         return getInputValue(0);
 461                 }
 462
 463                 /**
 464                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.
 465                  *         Returns the least significant bit (LSB)
 466                  *
 467                  */
 468                 public Bit getInputValue(int index)
 469                 {
 470                         return inputValues.getLSBit(index);
 471                 }
 472
 473                 /**
 474                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 475                  */
 476                 public BitVector getInputValues()
 477                 {
 478                         return inputValues;
 479                 }
 480
 481                 public BitVector getInputValues(int start, int end)
 482                 {
 483                         return inputValues.subVector(start, end);
 484                 }
 485
 486                 /**
 487                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.
 488                  */
 489                 public void clearSignals()
 490                 {
 491                         feedSignals(Z.toVector(length));
 492                 }
 493
 494                 public BitVector wireValuesExcludingMe()
 495                 {
 496                         BitVectorMutator mutator = BitVectorMutator.empty();
 497                         for (ReadWriteEnd wireEnd : inputs)
 498                         {
 499                                 if (wireEnd == this)
 500                                         continue;
 501                                 mutator.join(wireEnd.inputValues);
 502                         }
 503                         return mutator.toBitVector();
 504                 }
 505
 506                 @Override
 507                 public String toString()
 508                 {
 509                         return inputValues.toString();
 510                 }
 511
 512                 @Override
 513                 public void close()
 514                 {
 515                         super.close();
 516                         open = false;
 517                 }
 518
 519                 void setWriting(boolean isWriting)
 520                 {
 521                         if (this.isWriting != isWriting)
 522                         {
 523                                 this.isWriting = isWriting;
 524                                 if (isWriting)
 525                                         inputs.add(this);
 526                                 else
 527                                         inputs.remove(this);
 528                                 Wire.this.recalculate();
 529                         }
 530                 }
 531
 532                 boolean isWriting()
 533                 {
 534                         return isWriting;
 535                 }
 536         }
 537
 538         @Override
 539         public String toString()
 540         {
 541                 String name = this.name == null ? String.format("0x%08x", hashCode()) : this.name;
 542                 return String.format("wire %s value: %s inputs: %s", name, values, inputs);
 543         }
 544
 545         public static ReadEnd[] extractEnds(Wire[] w)
 546         {
 547                 ReadEnd[] inputs = new ReadEnd[w.length];
 548                 for (int i = 0; i < w.length; i++)
 549                         inputs[i] = w[i].createReadWriteEnd();
 550                 return inputs;
 551         }
 552
 553         // TODO Fix ReadWriteEnd feeding signals to entire Wire (Z) instead of only selected Bits
 554         /**
 555          * Fuses the selected bits of two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning:
 556          * The bits are permanently fused together.
 557          *
 558          * @param a      The {@link Wire} to be (partially) fused with b
 559          * @param b      The {@link Wire} to be (partially) fused with a
 560          * @param fromA  The first bit of {@link Wire} a to be fused
 561          * @param fromB  The first bit of {@link Wire} b to be fused
 562          * @param length The amount of bits to fuse
 563          */
 564         public static void fuse(Wire a, Wire b, int fromA, int fromB, int length)
 565         {
 566                 ReadWriteEnd rA = a.createReadWriteEnd(), rB = b.createReadWriteEnd();
 567                 rA.setWriting(false);
 568                 rB.setWriting(false);
 569                 rA.setValues(BitVector.of(Bit.Z, a.length));
 570                 rB.setValues(BitVector.of(Bit.Z, b.length));
 571                 Fusion aF = new Fusion(rB, fromA, fromB, length), bF = new Fusion(rA, fromB, fromA, length);
 572                 rA.registerObserver(aF);
 573                 rB.registerObserver(bF);
 574                 aF.update(rA);
 575                 bF.update(rB);
 576         }
 577
 578         /**
 579          *
 580          * Fuses two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning: The bits are
 581          * permanently fused together.
 582          *
 583          * @param a The {@link Wire} to be fused with b
 584          * @param b The {@link Wire} to be fused with a
 585          */
 586         public static void fuse(Wire a, Wire b)
 587         {
 588                 fuse(a, b, 0, 0, a.length);
 589         }
 590
 591         private static class Fusion implements LogicObserver
 592         {
 593                 private ReadWriteEnd target;
 594                 int fromSource, fromTarget, length;
 595
 596                 public Fusion(ReadWriteEnd target, int fromSource, int fromTarget, int length)
 597                 {
 598                         this.target = target;
 599                         this.fromSource = fromSource;
 600                         this.fromTarget = fromTarget;
 601                         this.length = length;
 602                 }
 603
 604                 @Override
 605                 public void update(LogicObservable initiator)
 606                 {
 607                         ReadWriteEnd source = (ReadWriteEnd) initiator;
 608                         if (source.getWire().inputs.size() - (source.isWriting() ? 1 : 0) == 0)
 609                                 target.setWriting(false);
 610                         else
 611                         {
 612                                 target.setWriting(true);
 613                                 BitVector targetInput = source.wireValuesExcludingMe().subVector(fromSource, fromSource + length);
 614                                 target.setValues(fromTarget, targetInput);
 615                         }
 616                 }
 617         }
 618 }