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