era.mi/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.timeline.Timeline;
  10 import net.mograsim.logic.core.types.Bit;
  11 import net.mograsim.logic.core.types.BitVector;
  12 import net.mograsim.logic.core.types.BitVector.BitVectorMutator;
  13
  14 /**
  15  * Represents an array of wires that can store n bits of information.
  16  *
  17  * @author Fabian Stemmler
  18  *
  19  */
  20 public class Wire
  21 {
  22         private BitVector values;
  23         public final int travelTime;
  24         private List<ReadEnd> attached = new ArrayList<ReadEnd>();
  25         public final int length;
  26         private List<ReadWriteEnd> inputs = new ArrayList<ReadWriteEnd>();
  27         private Timeline timeline;
  28
  29         public Wire(Timeline timeline, int length, int travelTime)
  30         {
  31                 if (length < 1)
  32                         throw new IllegalArgumentException(
  33                                         String.format("Tried to create an array of wires with length %d, but a length of less than 1 makes no sense.", length));
  34                 this.timeline = timeline;
  35                 this.length = length;
  36                 this.travelTime = travelTime;
  37                 initValues();
  38         }
  39
  40         private void initValues()
  41         {
  42                 values = U.toVector(length);
  43         }
  44
  45         private void recalculateSingleInput()
  46         {
  47                 setNewValues(inputs.get(0).getInputValues());
  48         }
  49
  50         private void recalculateMultipleInputs()
  51         {
  52                 BitVectorMutator mutator = BitVectorMutator.empty();
  53                 for (ReadWriteEnd wireArrayEnd : inputs)
  54                         mutator.join(wireArrayEnd.getInputValues());
  55                 setNewValues(mutator.get());
  56         }
  57
  58         private void setNewValues(BitVector newValues)
  59         {
  60                 if (values.equals(newValues))
  61                         return;
  62                 BitVector oldValues = values;
  63                 values = newValues;
  64                 notifyObservers(oldValues);
  65         }
  66
  67         private void recalculate()
  68         {
  69                 switch (inputs.size())
  70                 {
  71                 case 0:
  72                         return;
  73                 case 1:
  74                         recalculateSingleInput();
  75                         break;
  76                 default:
  77                         recalculateMultipleInputs();
  78                 }
  79         }
  80
  81         /**
  82          * The {@link Wire} is interpreted as an unsigned integer with n bits.
  83          *
  84          * @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
  85          *         value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
  86          *
  87          * @author Fabian Stemmler
  88          */
  89         public boolean hasNumericValue()
  90         {
  91                 for (Bit b : values)
  92                 {
  93                         if (b != Bit.ZERO && b != Bit.ONE)
  94                                 return false;
  95                 }
  96                 return true;
  97         }
  98
  99         /**
 100          * The {@link Wire} is interpreted as an unsigned integer with n bits.
 101          *
 102          * @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.
 103          *
 104          * @author Fabian Stemmler
 105          */
 106         public long getUnsignedValue()
 107         {
 108                 long val = 0;
 109                 long mask = 1;
 110                 for (Bit bit : values)
 111                 {
 112                         switch (bit)
 113                         {
 114                         default:
 115                         case Z:
 116                         case X:
 117                                 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;
 118                         case ONE:
 119                                 val |= mask;
 120                                 break;
 121                         case ZERO:
 122                         }
 123                         mask = mask << 1;
 124                 }
 125                 return val;
 126         }
 127
 128         /**
 129          * The {@link Wire} is interpreted as a signed integer with n bits.
 130          *
 131          * @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.
 132          *
 133          * @author Fabian Stemmler
 134          */
 135         public long getSignedValue()
 136         {
 137                 long val = getUnsignedValue();
 138                 long mask = 1 << (length - 1);
 139                 if ((mask & val) != 0)
 140                 {
 141                         int shifts = 64 - length;
 142                         return (val << shifts) >> shifts;
 143                 }
 144                 return val;
 145         }
 146
 147         public Bit getValue()
 148         {
 149                 return getValue(0);
 150         }
 151
 152         public Bit getValue(int index)
 153         {
 154                 return values.getBit(index);
 155         }
 156
 157         public BitVector getValues(int start, int end)
 158         {
 159                 return values.subVector(start, end);
 160         }
 161
 162         public BitVector getValues()
 163         {
 164                 return values;
 165         }
 166
 167         /**
 168          * Adds an {@link WireObserver}, who will be notified when the value of the {@link Wire} is updated.
 169          *
 170          * @param ob The {@link WireObserver} to be notified of changes.
 171          * @return true if the given {@link WireObserver} was not already registered, false otherwise
 172          *
 173          * @author Fabian Stemmler
 174          */
 175         private void attachEnd(ReadEnd end)
 176         {
 177                 attached.add(end);
 178         }
 179
 180         private void detachEnd(ReadEnd end)
 181         {
 182                 attached.remove(end);
 183         }
 184
 185         private void notifyObservers(BitVector oldValues)
 186         {
 187                 for (ReadEnd o : attached)
 188                         o.update(oldValues);
 189         }
 190
 191         /**
 192          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.
 193          */
 194         public ReadWriteEnd createReadWriteEnd()
 195         {
 196                 return new ReadWriteEnd();
 197         }
 198
 199         /**
 200          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.
 201          */
 202         public ReadEnd createReadOnlyEnd()
 203         {
 204                 return new ReadEnd();
 205         }
 206
 207         private void registerInput(ReadWriteEnd toRegister)
 208         {
 209                 inputs.add(toRegister);
 210         }
 211
 212         /**
 213          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the
 214          * {@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
 215          * and 1 turn into X when they are mixed
 216          *
 217          * @author Fabian Stemmler
 218          */
 219         public class ReadEnd
 220         {
 221                 private List<WireObserver> observers = new ArrayList<WireObserver>();
 222
 223                 private ReadEnd()
 224                 {
 225                         super();
 226                         Wire.this.attachEnd(this);
 227                 }
 228
 229                 public void update(BitVector oldValues)
 230                 {
 231                         for (WireObserver ob : observers)
 232                                 ob.update(this, oldValues);
 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 boolean addObserver(WireObserver ob)
 337                 {
 338                         return observers.add(ob);
 339                 }
 340
 341                 public Wire getWire()
 342                 {
 343                         return Wire.this;
 344                 }
 345         }
 346
 347         public class ReadWriteEnd extends ReadEnd
 348         {
 349                 private boolean open;
 350                 private BitVector inputValues;
 351
 352                 private ReadWriteEnd()
 353                 {
 354                         super();
 355                         open = true;
 356                         initValues();
 357                         registerInput(this);
 358                 }
 359
 360                 private void initValues()
 361                 {
 362                         inputValues = U.toVector(length);
 363                 }
 364
 365                 /**
 366                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.
 367                  *
 368                  * @param newValues The new values the wires should take on.
 369                  *
 370                  * @author Fabian Stemmler
 371                  */
 372                 public void feedSignals(Bit... newValues)
 373                 {
 374                         feedSignals(BitVector.of(newValues));
 375                 }
 376
 377                 public void feedSignals(BitVector newValues)
 378                 {
 379                         if (newValues.length() != length)
 380                                 throw new IllegalArgumentException(
 381                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));
 382                         if (!open)
 383                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 384                         timeline.addEvent(e -> setValues(newValues), travelTime);
 385                 }
 386
 387                 /**
 388                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.
 389                  *
 390                  * @param bitVector   The new values the wires should take on.
 391                  * @param startingBit The first index of the subarray of wires.
 392                  *
 393                  * @author Fabian Stemmler
 394                  */
 395                 public void feedSignals(int startingBit, BitVector bitVector)
 396                 {
 397                         if (!open)
 398                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
 399                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);
 400                 }
 401
 402                 private void setValues(int startingBit, BitVector newValues)
 403                 {
 404                         // index check covered in equals
 405                         if (!inputValues.equalsWithOffset(newValues, startingBit))
 406                         {
 407                                 Bit[] vals = inputValues.getBits();
 408                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());
 409                                 inputValues = BitVector.of(vals);
 410                                 Wire.this.recalculate();
 411                         }
 412                 }
 413
 414                 private void setValues(BitVector newValues)
 415                 {
 416                         if (inputValues.equals(newValues))
 417                                 return;
 418                         inputValues = newValues;
 419                         Wire.this.recalculate();
 420                 }
 421
 422                 /**
 423                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 424                  */
 425                 public Bit getInputValue()
 426                 {
 427                         return getInputValue(0);
 428                 }
 429
 430                 /**
 431                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.
 432                  */
 433                 public Bit getInputValue(int index)
 434                 {
 435                         return inputValues.getBit(index);
 436                 }
 437
 438                 /**
 439                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.
 440                  */
 441                 public BitVector getInputValues()
 442                 {
 443                         return getInputValues(0, length);
 444                 }
 445
 446                 public BitVector getInputValues(int start, int end)
 447                 {
 448                         return inputValues.subVector(start, end);
 449                 }
 450
 451                 /**
 452                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.
 453                  */
 454                 public void clearSignals()
 455                 {
 456                         feedSignals(Z.toVector(length));
 457                 }
 458
 459                 public BitVector wireValuesExcludingMe()
 460                 {
 461                         BitVectorMutator mutator = BitVectorMutator.empty();
 462                         for (ReadWriteEnd wireEnd : inputs)
 463                         {
 464                                 if (wireEnd == this)
 465                                         continue;
 466                                 mutator.join(wireEnd.inputValues);
 467                         }
 468                         return mutator.get();
 469                 }
 470
 471                 @Override
 472                 public String toString()
 473                 {
 474                         return inputValues.toString();
 475                 }
 476         }
 477
 478         @Override
 479         public String toString()
 480         {
 481                 return String.format("wire 0x%08x value: %s inputs: %s", hashCode(), values, inputs);
 482                 // Arrays.toString(values), inputs.stream().map(i -> Arrays.toString(i.inputValues)).reduce((s1, s2) -> s1 + s2)
 483         }
 484
 485         public static ReadEnd[] extractEnds(Wire[] w)
 486         {
 487                 ReadEnd[] inputs = new ReadEnd[w.length];
 488                 for (int i = 0; i < w.length; i++)
 489                         inputs[i] = w[i].createReadWriteEnd();
 490                 return inputs;
 491         }
 492 }