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         public Bit getValue()
 154         {
 155                 return getValue(0);
 156         }
 157
 158         public Bit getValue(int index)
 159         {
 160                 return values.getBit(index);
 161         }
 162
 163         public BitVector getValues(int start, int end)
 164         {
 165                 return values.subVector(start, end);
 166         }
 167
 168         public BitVector getValues()
 169         {
 170                 return values;
 171         }
 172
 173         /**
 174          * Adds an {@link LogicObserver}, who will be notified when the value of the {@link Wire} is updated.
 175          *
 176          * @param ob The {@link LogicObserver} to be notified of changes.
 177          * @return true if the given {@link LogicObserver} was not already registered, false otherwise
 178          *
 179          * @author Fabian Stemmler
 180          */
 181         void attachEnd(ReadEnd end)
 182         {
 183                 attached.add(end);
 184         }
 185
 186         void detachEnd(ReadEnd end)
 187         {
 188                 attached.remove(end);
 189         }
 190
 191         private void notifyObservers()
 192         {
 193                 attached.forEach(r -> r.update());
 194         }
 195
 196         /**
 197          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.
 198          */
 199         public ReadWriteEnd createReadWriteEnd()
 200         {
 201                 return new ReadWriteEnd();
 202         }
 203
 204         /**
 205          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.
 206          */
 207         public ReadEnd createReadOnlyEnd()
 208         {
 209                 return new ReadEnd();
 210         }
 211
 212         void registerInput(ReadWriteEnd toRegister)
 213         {
 214                 inputs.add(toRegister);
 215         }
 216
 217         /**
 218          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the
 219          * {@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
 220          * and 1 turn into X when they are mixed
 221          *
 222          * @author Fabian Stemmler
 223          */
 224         public class ReadEnd implements LogicObservable
 225         {
 226                 private List<LogicObserver> observers = new ArrayList<>();
 227
 228                 ReadEnd()
 229                 {
 230                         super();
 231                         Wire.this.attachEnd(this);
 232                 }
 233
 234                 public void update()
 235                 {
 236                         notifyObservers();
 237                 }
 238
 239                 /**
 240                  * Included for convenient use on {@link Wire}s of length 1.
 241                  *
 242                  * @return The value of bit 0.
 243                  *
 244                  * @author Fabian Stemmler
 245                  */
 246                 public Bit getValue()
 247                 {
 248                         return Wire.this.getValue();
 249                 }
 250
 251                 /**
 252                  * @param index Index of the requested bit.
 253                  * @return The value of the indexed bit.
 254                  *
 255                  * @author Fabian Stemmler
 256                  */
 257                 public Bit getValue(int index)
 258                 {
 259                         return Wire.this.getValue(index);
 260                 }
 261
 262                 /**
 263                  * @param index Index of the requested bit.
 264                  * @return The value of the indexed bit.
 265                  *
 266                  * @author Fabian Stemmler
 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}.
 450                  */
 451                 public Bit getInputValue()
 452                 {
 453                         return getInputValue(0);
 454                 }
 455
 456                 /**
 457                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.
 458                  */
 459                 public Bit getInputValue(int index)
 460                 {
 461                         return inputValues.getBit(index);
 462                 }
 463
 464                 /**
 465                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 466                  */
 467                 public BitVector getInputValues()
 468                 {
 469                         return getInputValues(0, length);
 470                 }
 471
 472                 public BitVector getInputValues(int start, int end)
 473                 {
 474                         return inputValues.subVector(start, end);
 475                 }
 476
 477                 /**
 478                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.
 479                  */
 480                 public void clearSignals()
 481                 {
 482                         feedSignals(Z.toVector(length));
 483                 }
 484
 485                 public BitVector wireValuesExcludingMe()
 486                 {
 487                         BitVectorMutator mutator = BitVectorMutator.empty();
 488                         for (ReadWriteEnd wireEnd : inputs)
 489                         {
 490                                 if (wireEnd == this)
 491                                         continue;
 492                                 mutator.join(wireEnd.inputValues);
 493                         }
 494                         return mutator.toBitVector();
 495                 }
 496
 497                 @Override
 498                 public String toString()
 499                 {
 500                         return inputValues.toString();
 501                 }
 502
 503                 @Override
 504                 public void close()
 505                 {
 506                         super.close();
 507                         open = false;
 508                 }
 509
 510                 void setWriting(boolean isWriting)
 511                 {
 512                         if (this.isWriting != isWriting)
 513                         {
 514                                 this.isWriting = isWriting;
 515                                 if (isWriting)
 516                                         inputs.add(this);
 517                                 else
 518                                         inputs.remove(this);
 519                                 Wire.this.recalculate();
 520                         }
 521                 }
 522
 523                 boolean isWriting()
 524                 {
 525                         return isWriting;
 526                 }
 527         }
 528
 529         @Override
 530         public String toString()
 531         {
 532                 String name = this.name == null ? String.format("0x%08x", hashCode()) : this.name;
 533                 return String.format("wire %s value: %s inputs: %s", name, values, inputs);
 534         }
 535
 536         public static ReadEnd[] extractEnds(Wire[] w)
 537         {
 538                 ReadEnd[] inputs = new ReadEnd[w.length];
 539                 for (int i = 0; i < w.length; i++)
 540                         inputs[i] = w[i].createReadWriteEnd();
 541                 return inputs;
 542         }
 543
 544         // TODO Fix ReadWriteEnd feeding signals to entire Wire (Z) instead of only selected Bits
 545         /**
 546          * Fuses the selected bits of two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning:
 547          * The bits are permanently fused together.
 548          *
 549          * @param a      The {@link Wire} to be (partially) fused with b
 550          * @param b      The {@link Wire} to be (partially) fused with a
 551          * @param fromA  The first bit of {@link Wire} a to be fused
 552          * @param fromB  The first bit of {@link Wire} b to be fused
 553          * @param length The amount of bits to fuse
 554          */
 555         public static void fuse(Wire a, Wire b, int fromA, int fromB, int length)
 556         {
 557                 ReadWriteEnd rA = a.createReadWriteEnd(), rB = b.createReadWriteEnd();
 558                 rA.setWriting(false);
 559                 rB.setWriting(false);
 560                 rA.setValues(BitVector.of(Bit.Z, a.length));
 561                 rB.setValues(BitVector.of(Bit.Z, b.length));
 562                 Fusion aF = new Fusion(rB, fromA, fromB, length), bF = new Fusion(rA, fromB, fromA, length);
 563                 rA.registerObserver(aF);
 564                 rB.registerObserver(bF);
 565                 aF.update(rA);
 566                 bF.update(rB);
 567         }
 568
 569         /**
 570          *
 571          * Fuses two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning: The bits are
 572          * permanently fused together.
 573          *
 574          * @param a The {@link Wire} to be fused with b
 575          * @param b The {@link Wire} to be fused with a
 576          */
 577         public static void fuse(Wire a, Wire b)
 578         {
 579                 fuse(a, b, 0, 0, a.length);
 580         }
 581
 582         private static class Fusion implements LogicObserver
 583         {
 584                 private ReadWriteEnd target;
 585                 int fromSource, fromTarget, length;
 586
 587                 public Fusion(ReadWriteEnd target, int fromSource, int fromTarget, int length)
 588                 {
 589                         this.target = target;
 590                         this.fromSource = fromSource;
 591                         this.fromTarget = fromTarget;
 592                         this.length = length;
 593                 }
 594
 595                 @Override
 596                 public void update(LogicObservable initiator)
 597                 {
 598                         ReadWriteEnd source = (ReadWriteEnd) initiator;
 599                         if (source.getWire().inputs.size() - (source.isWriting() ? 1 : 0) == 0)
 600                                 target.setWriting(false);
 601                         else
 602                         {
 603                                 target.setWriting(true);
 604                                 BitVector targetInput = source.wireValuesExcludingMe().subVector(fromSource, fromSource + length);
 605                                 target.setValues(fromTarget, targetInput);
 606                         }
 607                 }
 608         }
 609 }