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                 public BitVector getValues()
 269                 {
 270                         return Wire.this.getValues();
 271                 }
 272
 273                 /**
 274                  * @param start Start of the wanted segment. (inclusive)
 275                  * @param end   End of the wanted segment. (exclusive)
 276                  * @return The values of the segment of {@link Bit}s indexed.
 277                  *
 278                  * @author Fabian Stemmler
 279                  */
 280                 public BitVector getValues(int start, int end)
 281                 {
 282                         return Wire.this.getValues(start, end);
 283                 }
 284
 285                 /**
 286                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 287                  *
 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
 289                  *         same value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
 290                  *
 291                  * @author Fabian Stemmler
 292                  */
 293                 public boolean hasNumericValue()
 294                 {
 295                         return Wire.this.hasNumericValue();
 296                 }
 297
 298                 /**
 299                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 300                  *
 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.
 302                  *
 303                  * @author Fabian Stemmler
 304                  */
 305                 public long getUnsignedValue()
 306                 {
 307                         return Wire.this.getUnsignedValue();
 308                 }
 309
 310                 /**
 311                  * The {@link Wire} is interpreted as a signed integer with n bits.
 312                  *
 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.
 314                  *
 315                  * @author Fabian Stemmler
 316                  */
 317                 public long getSignedValue()
 318                 {
 319                         return Wire.this.getSignedValue();
 320                 }
 321
 322                 @Override
 323                 public String toString()
 324                 {
 325                         return Wire.this.toString();
 326                 }
 327
 328                 public void close()
 329                 {
 330                         inputs.remove(this);
 331                         detachEnd(this);
 332                         recalculate();
 333                 }
 334
 335                 public int length()
 336                 {
 337                         return length;
 338                 }
 339
 340                 public Wire getWire()
 341                 {
 342                         return Wire.this;
 343                 }
 344
 345                 @Override
 346                 public void registerObserver(LogicObserver ob)
 347                 {
 348                         observers.add(ob);
 349                 }
 350
 351                 @Override
 352                 public void deregisterObserver(LogicObserver ob)
 353                 {
 354                         observers.remove(ob);
 355                 }
 356
 357                 @Override
 358                 public void notifyObservers()
 359                 {
 360                         observers.forEach(ob -> ob.update(this));
 361                 }
 362         }
 363
 364         public class ReadWriteEnd extends ReadEnd
 365         {
 366                 private boolean open, isWriting;
 367                 private BitVector inputValues;
 368
 369                 ReadWriteEnd()
 370                 {
 371                         super();
 372                         open = true;
 373                         isWriting = true;
 374                         initValues();
 375                         registerInput(this);
 376                 }
 377
 378                 private void initValues()
 379                 {
 380                         inputValues = U.toVector(length);
 381                 }
 382
 383                 /**
 384                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.
 385                  *
 386                  * @param newValues The new values the wires should take on.
 387                  *
 388                  * @author Fabian Stemmler
 389                  */
 390                 public void feedSignals(Bit... newValues)
 391                 {
 392                         feedSignals(BitVector.of(newValues));
 393                 }
 394
 395                 public void feedSignals(BitVector newValues)
 396                 {
 397                         if (newValues.length() != length)
 398                                 throw new IllegalArgumentException(
 399                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));
 400                         if (!open)
 401                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 402                         timeline.addEvent(e -> setValues(newValues), travelTime);
 403                 }
 404
 405                 /**
 406                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.
 407                  *
 408                  * @param bitVector   The new values the wires should take on.
 409                  * @param startingBit The first index of the subarray of wires.
 410                  *
 411                  * @author Fabian Stemmler
 412                  */
 413                 public void feedSignals(int startingBit, BitVector bitVector)
 414                 {
 415                         if (!open)
 416                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 417                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);
 418                 }
 419
 420                 /**
 421                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via
 422                  * feedValues(...) with a delay.
 423                  */
 424                 void setValues(int startingBit, BitVector newValues)
 425                 {
 426                         // index check covered in equals
 427                         if (!inputValues.equalsWithOffset(newValues, startingBit))
 428                         {
 429                                 Bit[] vals = inputValues.getBits();
 430                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());
 431                                 inputValues = BitVector.of(vals);
 432                                 Wire.this.recalculate();
 433                         }
 434                 }
 435
 436                 /**
 437                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via
 438                  * feedValues(...) with a delay.
 439                  */
 440                 void setValues(BitVector newValues)
 441                 {
 442                         if (inputValues.equals(newValues))
 443                                 return;
 444                         inputValues = newValues;
 445                         Wire.this.recalculate();
 446                 }
 447
 448                 /**
 449                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.Returns the least
 450                  *         significant bit (LSB)
 451                  */
 452                 public Bit getInputValue()
 453                 {
 454                         return getInputValue(0);
 455                 }
 456
 457                 /**
 458                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.
 459                  *         Returns the least significant bit (LSB)
 460                  *
 461                  */
 462                 public Bit getInputValue(int index)
 463                 {
 464                         return inputValues.getLSBit(index);
 465                 }
 466
 467                 /**
 468                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 469                  */
 470                 public BitVector getInputValues()
 471                 {
 472                         return inputValues;
 473                 }
 474
 475                 public BitVector getInputValues(int start, int end)
 476                 {
 477                         return inputValues.subVector(start, end);
 478                 }
 479
 480                 /**
 481                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.
 482                  */
 483                 public void clearSignals()
 484                 {
 485                         feedSignals(Z.toVector(length));
 486                 }
 487
 488                 public BitVector wireValuesExcludingMe()
 489                 {
 490                         BitVectorMutator mutator = BitVectorMutator.empty();
 491                         for (ReadWriteEnd wireEnd : inputs)
 492                         {
 493                                 if (wireEnd == this)
 494                                         continue;
 495                                 mutator.join(wireEnd.inputValues);
 496                         }
 497                         return mutator.toBitVector();
 498                 }
 499
 500                 @Override
 501                 public String toString()
 502                 {
 503                         return inputValues.toString();
 504                 }
 505
 506                 @Override
 507                 public void close()
 508                 {
 509                         super.close();
 510                         open = false;
 511                 }
 512
 513                 void setWriting(boolean isWriting)
 514                 {
 515                         if (this.isWriting != isWriting)
 516                         {
 517                                 this.isWriting = isWriting;
 518                                 if (isWriting)
 519                                         inputs.add(this);
 520                                 else
 521                                         inputs.remove(this);
 522                                 Wire.this.recalculate();
 523                         }
 524                 }
 525
 526                 boolean isWriting()
 527                 {
 528                         return isWriting;
 529                 }
 530         }
 531
 532         @Override
 533         public String toString()
 534         {
 535                 String name = this.name == null ? String.format("0x%08x", hashCode()) : this.name;
 536                 return String.format("wire %s value: %s inputs: %s", name, values, inputs);
 537         }
 538
 539         public static ReadEnd[] extractEnds(Wire[] w)
 540         {
 541                 ReadEnd[] inputs = new ReadEnd[w.length];
 542                 for (int i = 0; i < w.length; i++)
 543                         inputs[i] = w[i].createReadWriteEnd();
 544                 return inputs;
 545         }
 546
 547         // TODO Fix ReadWriteEnd feeding signals to entire Wire (Z) instead of only selected Bits
 548         /**
 549          * Fuses the selected bits of two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning:
 550          * The bits are permanently fused together.
 551          *
 552          * @param a      The {@link Wire} to be (partially) fused with b
 553          * @param b      The {@link Wire} to be (partially) fused with a
 554          * @param fromA  The first bit of {@link Wire} a to be fused
 555          * @param fromB  The first bit of {@link Wire} b to be fused
 556          * @param length The amount of bits to fuse
 557          */
 558         public static void fuse(Wire a, Wire b, int fromA, int fromB, int length)
 559         {
 560                 ReadWriteEnd rA = a.createReadWriteEnd(), rB = b.createReadWriteEnd();
 561                 rA.setWriting(false);
 562                 rB.setWriting(false);
 563                 rA.setValues(BitVector.of(Bit.Z, a.length));
 564                 rB.setValues(BitVector.of(Bit.Z, b.length));
 565                 Fusion aF = new Fusion(rB, fromA, fromB, length), bF = new Fusion(rA, fromB, fromA, length);
 566                 rA.registerObserver(aF);
 567                 rB.registerObserver(bF);
 568                 aF.update(rA);
 569                 bF.update(rB);
 570         }
 571
 572         /**
 573          *
 574          * Fuses two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning: The bits are
 575          * permanently fused together.
 576          *
 577          * @param a The {@link Wire} to be fused with b
 578          * @param b The {@link Wire} to be fused with a
 579          */
 580         public static void fuse(Wire a, Wire b)
 581         {
 582                 fuse(a, b, 0, 0, a.length);
 583         }
 584
 585         private static class Fusion implements LogicObserver
 586         {
 587                 private ReadWriteEnd target;
 588                 int fromSource, fromTarget, length;
 589
 590                 public Fusion(ReadWriteEnd target, int fromSource, int fromTarget, int length)
 591                 {
 592                         this.target = target;
 593                         this.fromSource = fromSource;
 594                         this.fromTarget = fromTarget;
 595                         this.length = length;
 596                 }
 597
 598                 @Override
 599                 public void update(LogicObservable initiator)
 600                 {
 601                         ReadWriteEnd source = (ReadWriteEnd) initiator;
 602                         if (source.getWire().inputs.size() - (source.isWriting() ? 1 : 0) == 0)
 603                                 target.setWriting(false);
 604                         else
 605                         {
 606                                 target.setWriting(true);
 607                                 BitVector targetInput = source.wireValuesExcludingMe().subVector(fromSource, fromSource + length);
 608                                 target.setValues(fromTarget, targetInput);
 609                         }
 610                 }
 611         }
 612 }