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<ReadEnd>();
  27         public final int length;
  28         private List<ReadWriteEnd> inputs = new ArrayList<ReadWriteEnd>();
  29         private 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(oldValues);
  67         }
  68
  69         private 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         private void attachEnd(ReadEnd end)
 178         {
 179                 attached.add(end);
 180         }
 181
 182         private void detachEnd(ReadEnd end)
 183         {
 184                 attached.remove(end);
 185         }
 186
 187         private void notifyObservers(BitVector oldValues)
 188         {
 189                 for (ReadEnd o : attached)
 190                         o.update(oldValues);
 191         }
 192
 193         /**
 194          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.
 195          */
 196         public ReadWriteEnd createReadWriteEnd()
 197         {
 198                 return new ReadWriteEnd();
 199         }
 200
 201         /**
 202          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.
 203          */
 204         public ReadEnd createReadOnlyEnd()
 205         {
 206                 return new ReadEnd();
 207         }
 208
 209         private void registerInput(ReadWriteEnd toRegister)
 210         {
 211                 inputs.add(toRegister);
 212         }
 213
 214         /**
 215          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the
 216          * {@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
 217          * and 1 turn into X when they are mixed
 218          *
 219          * @author Fabian Stemmler
 220          */
 221         public class ReadEnd implements LogicObservable
 222         {
 223                 private List<LogicObserver> observers = new ArrayList<LogicObserver>();
 224
 225                 private ReadEnd()
 226                 {
 227                         super();
 228                         Wire.this.attachEnd(this);
 229                 }
 230
 231                 public void update(BitVector oldValues)
 232                 {
 233                         notifyObservers();
 234                 }
 235
 236                 /**
 237                  * Included for convenient use on {@link Wire}s of length 1.
 238                  *
 239                  * @return The value of bit 0.
 240                  *
 241                  * @author Fabian Stemmler
 242                  */
 243                 public Bit getValue()
 244                 {
 245                         return Wire.this.getValue();
 246                 }
 247
 248                 /**
 249                  * @param index Index of the requested bit.
 250                  * @return The value of the indexed bit.
 251                  *
 252                  * @author Fabian Stemmler
 253                  */
 254                 public Bit getValue(int index)
 255                 {
 256                         return Wire.this.getValue(index);
 257                 }
 258
 259                 /**
 260                  * @param index Index of the requested bit.
 261                  * @return The value of the indexed bit.
 262                  *
 263                  * @author Fabian Stemmler
 264                  */
 265                 public BitVector getValues()
 266                 {
 267                         return Wire.this.getValues();
 268                 }
 269
 270                 /**
 271                  * @param start Start of the wanted segment. (inclusive)
 272                  * @param end   End of the wanted segment. (exclusive)
 273                  * @return The values of the segment of {@link Bit}s indexed.
 274                  *
 275                  * @author Fabian Stemmler
 276                  */
 277                 public BitVector getValues(int start, int end)
 278                 {
 279                         return Wire.this.getValues(start, end);
 280                 }
 281
 282                 /**
 283                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 284                  *
 285                  * @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
 286                  *         same value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
 287                  *
 288                  * @author Fabian Stemmler
 289                  */
 290                 public boolean hasNumericValue()
 291                 {
 292                         return Wire.this.hasNumericValue();
 293                 }
 294
 295                 /**
 296                  * The {@link Wire} is interpreted as an unsigned integer with n bits.
 297                  *
 298                  * @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.
 299                  *
 300                  * @author Fabian Stemmler
 301                  */
 302                 public long getUnsignedValue()
 303                 {
 304                         return Wire.this.getUnsignedValue();
 305                 }
 306
 307                 /**
 308                  * The {@link Wire} is interpreted as a signed integer with n bits.
 309                  *
 310                  * @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.
 311                  *
 312                  * @author Fabian Stemmler
 313                  */
 314                 public long getSignedValue()
 315                 {
 316                         return Wire.this.getSignedValue();
 317                 }
 318
 319                 @Override
 320                 public String toString()
 321                 {
 322                         return Wire.this.toString();
 323                 }
 324
 325                 public void close()
 326                 {
 327                         inputs.remove(this);
 328                         detachEnd(this);
 329                         recalculate();
 330                 }
 331
 332                 public int length()
 333                 {
 334                         return length;
 335                 }
 336
 337                 public Wire getWire()
 338                 {
 339                         return Wire.this;
 340                 }
 341
 342                 @Override
 343                 public void registerObserver(LogicObserver ob)
 344                 {
 345                         observers.add(ob);
 346                 }
 347
 348                 @Override
 349                 public void notifyObservers()
 350                 {
 351                         for (LogicObserver ob : observers)
 352                                 ob.update(this);
 353                 }
 354         }
 355
 356         public class ReadWriteEnd extends ReadEnd
 357         {
 358                 private boolean open;
 359                 private BitVector inputValues;
 360
 361                 private ReadWriteEnd()
 362                 {
 363                         super();
 364                         open = true;
 365                         initValues();
 366                         registerInput(this);
 367                 }
 368
 369                 private void initValues()
 370                 {
 371                         inputValues = U.toVector(length);
 372                 }
 373
 374                 /**
 375                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.
 376                  *
 377                  * @param newValues The new values the wires should take on.
 378                  *
 379                  * @author Fabian Stemmler
 380                  */
 381                 public void feedSignals(Bit... newValues)
 382                 {
 383                         feedSignals(BitVector.of(newValues));
 384                 }
 385
 386                 public void feedSignals(BitVector newValues)
 387                 {
 388                         if (newValues.length() != length)
 389                                 throw new IllegalArgumentException(
 390                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));
 391                         if (!open)
 392                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 393                         timeline.addEvent(e -> setValues(newValues), travelTime);
 394                 }
 395
 396                 /**
 397                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.
 398                  *
 399                  * @param bitVector   The new values the wires should take on.
 400                  * @param startingBit The first index of the subarray of wires.
 401                  *
 402                  * @author Fabian Stemmler
 403                  */
 404                 public void feedSignals(int startingBit, BitVector bitVector)
 405                 {
 406                         if (!open)
 407                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 408                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);
 409                 }
 410
 411                 private void setValues(int startingBit, BitVector newValues)
 412                 {
 413                         // index check covered in equals
 414                         if (!inputValues.equalsWithOffset(newValues, startingBit))
 415                         {
 416                                 Bit[] vals = inputValues.getBits();
 417                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());
 418                                 inputValues = BitVector.of(vals);
 419                                 Wire.this.recalculate();
 420                         }
 421                 }
 422
 423                 private void setValues(BitVector newValues)
 424                 {
 425                         if (inputValues.equals(newValues))
 426                                 return;
 427                         inputValues = newValues;
 428                         Wire.this.recalculate();
 429                 }
 430
 431                 /**
 432                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 433                  */
 434                 public Bit getInputValue()
 435                 {
 436                         return getInputValue(0);
 437                 }
 438
 439                 /**
 440                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.
 441                  */
 442                 public Bit getInputValue(int index)
 443                 {
 444                         return inputValues.getBit(index);
 445                 }
 446
 447                 /**
 448                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 449                  */
 450                 public BitVector getInputValues()
 451                 {
 452                         return getInputValues(0, length);
 453                 }
 454
 455                 public BitVector getInputValues(int start, int end)
 456                 {
 457                         return inputValues.subVector(start, end);
 458                 }
 459
 460                 /**
 461                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.
 462                  */
 463                 public void clearSignals()
 464                 {
 465                         feedSignals(Z.toVector(length));
 466                 }
 467
 468                 public BitVector wireValuesExcludingMe()
 469                 {
 470                         BitVectorMutator mutator = BitVectorMutator.empty();
 471                         for (ReadWriteEnd wireEnd : inputs)
 472                         {
 473                                 if (wireEnd == this)
 474                                         continue;
 475                                 mutator.join(wireEnd.inputValues);
 476                         }
 477                         return mutator.get();
 478                 }
 479
 480                 @Override
 481                 public String toString()
 482                 {
 483                         return inputValues.toString();
 484                 }
 485         }
 486
 487         @Override
 488         public String toString()
 489         {
 490                 return String.format("wire 0x%08x value: %s inputs: %s", hashCode(), values, inputs);
 491         }
 492
 493         public static ReadEnd[] extractEnds(Wire[] w)
 494         {
 495                 ReadEnd[] inputs = new ReadEnd[w.length];
 496                 for (int i = 0; i < w.length; i++)
 497                         inputs[i] = w[i].createReadWriteEnd();
 498                 return inputs;
 499         }
 500 }