net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java

   1 package net.mograsim.logic.core.wires;\r
   2 \r
   3 import static net.mograsim.logic.core.types.Bit.U;\r
   4 import static net.mograsim.logic.core.types.Bit.Z;\r
   5 \r
   6 import java.util.ArrayList;\r
   7 import java.util.List;\r
   8 \r
   9 import net.mograsim.logic.core.LogicObservable;\r
  10 import net.mograsim.logic.core.LogicObserver;\r
  11 import net.mograsim.logic.core.timeline.Timeline;\r
  12 import net.mograsim.logic.core.types.Bit;\r
  13 import net.mograsim.logic.core.types.BitVector;\r
  14 import net.mograsim.logic.core.types.BitVector.BitVectorMutator;\r
  15 \r
  16 /**\r
  17  * Represents an array of wires that can store n bits of information.\r
  18  * \r
  19  * @author Fabian Stemmler\r
  20  *\r
  21  */\r
  22 public class Wire\r
  23 {\r
  24         public final String name;\r
  25         private BitVector values;\r
  26         public final int travelTime;\r
  27         private List<ReadEnd> attached = new ArrayList<>();\r
  28         public final int length;\r
  29         List<ReadWriteEnd> inputs = new ArrayList<>();\r
  30         Timeline timeline;\r
  31 \r
  32         public Wire(Timeline timeline, int length, int travelTime)\r
  33         {\r
  34                 this(timeline, length, travelTime, null);\r
  35         }\r
  36 \r
  37         public Wire(Timeline timeline, int length, int travelTime, String name)\r
  38         {\r
  39                 if (length < 1)\r
  40                         throw new IllegalArgumentException(\r
  41                                         String.format("Tried to create an array of wires with length %d, but a length of less than 1 makes no sense.", length));\r
  42                 this.name = name;\r
  43                 this.timeline = timeline;\r
  44                 this.length = length;\r
  45                 this.travelTime = travelTime;\r
  46                 initValues();\r
  47         }\r
  48 \r
  49         private void initValues()\r
  50         {\r
  51                 values = U.toVector(length);\r
  52         }\r
  53 \r
  54         private void setNewValues(BitVector newValues)\r
  55         {\r
  56                 if (values.equals(newValues))\r
  57                         return;\r
  58 //              BitVector oldValues = values;\r
  59                 values = newValues;\r
  60                 notifyObservers();\r
  61         }\r
  62 \r
  63         void recalculate()\r
  64         {\r
  65                 if (inputs.size() == 0)\r
  66                         setNewValues(BitVector.of(Bit.U, length));\r
  67                 else\r
  68                 {\r
  69                         BitVectorMutator mutator = BitVectorMutator.empty();\r
  70                         for (ReadWriteEnd wireArrayEnd : inputs)\r
  71                                 mutator.join(wireArrayEnd.getInputValues());\r
  72                         setNewValues(mutator.toBitVector());\r
  73                 }\r
  74         }\r
  75 \r
  76         /**\r
  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.\r
  78          * WARNING! Use this with care! The preferred way of writing the values is ReadWriteEnd.feedSignals(BitVector)\r
  79          * \r
  80          * @param values The values the <code>Wire</code> will have immediately after this method is called\r
  81          */\r
  82         public void forceValues(BitVector values)\r
  83         {\r
  84                 setNewValues(values);\r
  85         }\r
  86 \r
  87         /**\r
  88          * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
  89          * \r
  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\r
  91          *         value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.\r
  92          * \r
  93          * @author Fabian Stemmler\r
  94          */\r
  95         public boolean hasNumericValue()\r
  96         {\r
  97                 for (Bit b : values)\r
  98                 {\r
  99                         if (b != Bit.ZERO && b != Bit.ONE)\r
 100                                 return false;\r
 101                 }\r
 102                 return true;\r
 103         }\r
 104 \r
 105         /**\r
 106          * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 107          * \r
 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.\r
 109          * \r
 110          * @author Fabian Stemmler\r
 111          */\r
 112         public long getUnsignedValue()\r
 113         {\r
 114                 long val = 0;\r
 115                 long mask = 1;\r
 116                 for (Bit bit : values)\r
 117                 {\r
 118                         switch (bit)\r
 119                         {\r
 120                         default:\r
 121                         case Z:\r
 122                         case X:\r
 123                                 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;\r
 124                         case ONE:\r
 125                                 val |= mask;\r
 126                                 break;\r
 127                         case ZERO:\r
 128                         }\r
 129                         mask = mask << 1;\r
 130                 }\r
 131                 return val;\r
 132         }\r
 133 \r
 134         /**\r
 135          * The {@link Wire} is interpreted as a signed integer with n bits.\r
 136          * \r
 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.\r
 138          * \r
 139          * @author Fabian Stemmler\r
 140          */\r
 141         public long getSignedValue()\r
 142         {\r
 143                 long val = getUnsignedValue();\r
 144                 long mask = 1 << (length - 1);\r
 145                 if ((mask & val) != 0)\r
 146                 {\r
 147                         int shifts = 64 - length;\r
 148                         return (val << shifts) >> shifts;\r
 149                 }\r
 150                 return val;\r
 151         }\r
 152 \r
 153         public Bit getValue()\r
 154         {\r
 155                 return getValue(0);\r
 156         }\r
 157 \r
 158         public Bit getValue(int index)\r
 159         {\r
 160                 return values.getBit(index);\r
 161         }\r
 162 \r
 163         public BitVector getValues(int start, int end)\r
 164         {\r
 165                 return values.subVector(start, end);\r
 166         }\r
 167 \r
 168         public BitVector getValues()\r
 169         {\r
 170                 return values;\r
 171         }\r
 172 \r
 173         /**\r
 174          * Adds an {@link LogicObserver}, who will be notified when the value of the {@link Wire} is updated.\r
 175          * \r
 176          * @param ob The {@link LogicObserver} to be notified of changes.\r
 177          * @return true if the given {@link LogicObserver} was not already registered, false otherwise\r
 178          * \r
 179          * @author Fabian Stemmler\r
 180          */\r
 181         void attachEnd(ReadEnd end)\r
 182         {\r
 183                 attached.add(end);\r
 184         }\r
 185 \r
 186         void detachEnd(ReadEnd end)\r
 187         {\r
 188                 attached.remove(end);\r
 189         }\r
 190 \r
 191         private void notifyObservers()\r
 192         {\r
 193                 attached.forEach(r -> r.update());\r
 194         }\r
 195 \r
 196         /**\r
 197          * Create and register a {@link ReadWriteEnd} object, which is tied to this {@link Wire}. This {@link ReadWriteEnd} can be written to.\r
 198          */\r
 199         public ReadWriteEnd createReadWriteEnd()\r
 200         {\r
 201                 return new ReadWriteEnd();\r
 202         }\r
 203 \r
 204         /**\r
 205          * Create a {@link ReadEnd} object, which is tied to this {@link Wire}. This {@link ReadEnd} cannot be written to.\r
 206          */\r
 207         public ReadEnd createReadOnlyEnd()\r
 208         {\r
 209                 return new ReadEnd();\r
 210         }\r
 211 \r
 212         void registerInput(ReadWriteEnd toRegister)\r
 213         {\r
 214                 inputs.add(toRegister);\r
 215         }\r
 216 \r
 217         /**\r
 218          * A {@link ReadEnd} feeds a constant signal into the {@link Wire} it is tied to. The combination of all inputs determines the\r
 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\r
 220          * and 1 turn into X when they are mixed\r
 221          * \r
 222          * @author Fabian Stemmler\r
 223          */\r
 224         public class ReadEnd implements LogicObservable\r
 225         {\r
 226                 private List<LogicObserver> observers = new ArrayList<>();\r
 227 \r
 228                 ReadEnd()\r
 229                 {\r
 230                         super();\r
 231                         Wire.this.attachEnd(this);\r
 232                 }\r
 233 \r
 234                 public void update()\r
 235                 {\r
 236                         notifyObservers();\r
 237                 }\r
 238 \r
 239                 /**\r
 240                  * Included for convenient use on {@link Wire}s of length 1.\r
 241                  * \r
 242                  * @return The value of bit 0.\r
 243                  * \r
 244                  * @author Fabian Stemmler\r
 245                  */\r
 246                 public Bit getValue()\r
 247                 {\r
 248                         return Wire.this.getValue();\r
 249                 }\r
 250 \r
 251                 /**\r
 252                  * @param index Index of the requested bit.\r
 253                  * @return The value of the indexed bit.\r
 254                  * \r
 255                  * @author Fabian Stemmler\r
 256                  */\r
 257                 public Bit getValue(int index)\r
 258                 {\r
 259                         return Wire.this.getValue(index);\r
 260                 }\r
 261 \r
 262                 /**\r
 263                  * @param index Index of the requested bit.\r
 264                  * @return The value of the indexed bit.\r
 265                  * \r
 266                  * @author Fabian Stemmler\r
 267                  */\r
 268                 public BitVector getValues()\r
 269                 {\r
 270                         return Wire.this.getValues();\r
 271                 }\r
 272 \r
 273                 /**\r
 274                  * @param start Start of the wanted segment. (inclusive)\r
 275                  * @param end   End of the wanted segment. (exclusive)\r
 276                  * @return The values of the segment of {@link Bit}s indexed.\r
 277                  * \r
 278                  * @author Fabian Stemmler\r
 279                  */\r
 280                 public BitVector getValues(int start, int end)\r
 281                 {\r
 282                         return Wire.this.getValues(start, end);\r
 283                 }\r
 284 \r
 285                 /**\r
 286                  * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 287                  * \r
 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\r
 289                  *         same value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.\r
 290                  * \r
 291                  * @author Fabian Stemmler\r
 292                  */\r
 293                 public boolean hasNumericValue()\r
 294                 {\r
 295                         return Wire.this.hasNumericValue();\r
 296                 }\r
 297 \r
 298                 /**\r
 299                  * The {@link Wire} is interpreted as an unsigned integer with n bits.\r
 300                  * \r
 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.\r
 302                  * \r
 303                  * @author Fabian Stemmler\r
 304                  */\r
 305                 public long getUnsignedValue()\r
 306                 {\r
 307                         return Wire.this.getUnsignedValue();\r
 308                 }\r
 309 \r
 310                 /**\r
 311                  * The {@link Wire} is interpreted as a signed integer with n bits.\r
 312                  * \r
 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.\r
 314                  * \r
 315                  * @author Fabian Stemmler\r
 316                  */\r
 317                 public long getSignedValue()\r
 318                 {\r
 319                         return Wire.this.getSignedValue();\r
 320                 }\r
 321 \r
 322                 @Override\r
 323                 public String toString()\r
 324                 {\r
 325                         return Wire.this.toString();\r
 326                 }\r
 327 \r
 328                 public void close()\r
 329                 {\r
 330                         inputs.remove(this);\r
 331                         detachEnd(this);\r
 332                         recalculate();\r
 333                 }\r
 334 \r
 335                 public int length()\r
 336                 {\r
 337                         return length;\r
 338                 }\r
 339 \r
 340                 public Wire getWire()\r
 341                 {\r
 342                         return Wire.this;\r
 343                 }\r
 344 \r
 345                 @Override\r
 346                 public void registerObserver(LogicObserver ob)\r
 347                 {\r
 348                         observers.add(ob);\r
 349                 }\r
 350 \r
 351                 @Override\r
 352                 public void deregisterObserver(LogicObserver ob)\r
 353                 {\r
 354                         observers.remove(ob);\r
 355                 }\r
 356 \r
 357                 @Override\r
 358                 public void notifyObservers()\r
 359                 {\r
 360                         observers.forEach(ob -> ob.update(this));\r
 361                 }\r
 362         }\r
 363 \r
 364         public class ReadWriteEnd extends ReadEnd\r
 365         {\r
 366                 private boolean open, isWriting;\r
 367                 private BitVector inputValues;\r
 368 \r
 369                 ReadWriteEnd()\r
 370                 {\r
 371                         super();\r
 372                         open = true;\r
 373                         isWriting = true;\r
 374                         initValues();\r
 375                         registerInput(this);\r
 376                 }\r
 377 \r
 378                 private void initValues()\r
 379                 {\r
 380                         inputValues = U.toVector(length);\r
 381                 }\r
 382 \r
 383                 /**\r
 384                  * Sets the wires values. This takes up time, as specified by the {@link Wire}s travel time.\r
 385                  * \r
 386                  * @param newValues The new values the wires should take on.\r
 387                  * \r
 388                  * @author Fabian Stemmler\r
 389                  */\r
 390                 public void feedSignals(Bit... newValues)\r
 391                 {\r
 392                         feedSignals(BitVector.of(newValues));\r
 393                 }\r
 394 \r
 395                 public void feedSignals(BitVector newValues)\r
 396                 {\r
 397                         if (newValues.length() != length)\r
 398                                 throw new IllegalArgumentException(\r
 399                                                 String.format("Attempted to input %d bits instead of %d bits.", newValues.length(), length));\r
 400                         if (!open)\r
 401                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");\r
 402                         timeline.addEvent(e -> setValues(newValues), travelTime);\r
 403                 }\r
 404 \r
 405                 /**\r
 406                  * Sets values of a subarray of wires. This takes up time, as specified by the {@link Wire}s travel time.\r
 407                  * \r
 408                  * @param bitVector   The new values the wires should take on.\r
 409                  * @param startingBit The first index of the subarray of wires.\r
 410                  * \r
 411                  * @author Fabian Stemmler\r
 412                  */\r
 413                 public void feedSignals(int startingBit, BitVector bitVector)\r
 414                 {\r
 415                         if (!open)\r
 416                                 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");\r
 417                         timeline.addEvent(e -> setValues(startingBit, bitVector), travelTime);\r
 418                 }\r
 419 \r
 420                 /**\r
 421                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via\r
 422                  * feedValues(...) with a delay.\r
 423                  */\r
 424                 void setValues(int startingBit, BitVector newValues)\r
 425                 {\r
 426                         // index check covered in equals\r
 427                         if (!inputValues.equalsWithOffset(newValues, startingBit))\r
 428                         {\r
 429                                 Bit[] vals = inputValues.getBits();\r
 430                                 System.arraycopy(newValues.getBits(), 0, vals, startingBit, newValues.length());\r
 431                                 inputValues = BitVector.of(vals);\r
 432                                 Wire.this.recalculate();\r
 433                         }\r
 434                 }\r
 435 \r
 436                 /**\r
 437                  * Sets the values that are being fed into the {@link Wire}. The preferred way of setting {@link ReadWriteEnd} values is via\r
 438                  * feedValues(...) with a delay.\r
 439                  */\r
 440                 void setValues(BitVector newValues)\r
 441                 {\r
 442                         if (inputValues.equals(newValues))\r
 443                                 return;\r
 444                         inputValues = newValues;\r
 445                         Wire.this.recalculate();\r
 446                 }\r
 447 \r
 448                 /**\r
 449                  * @return The value (of bit 0) the {@link ReadEnd} is currently feeding into the associated {@link Wire}.\r
 450                  */\r
 451                 public Bit getInputValue()\r
 452                 {\r
 453                         return getInputValue(0);\r
 454                 }\r
 455 \r
 456                 /**\r
 457                  * @return The value which the {@link ReadEnd} is currently feeding into the associated {@link Wire} at the indexed {@link Bit}.\r
 458                  */\r
 459                 public Bit getInputValue(int index)\r
 460                 {\r
 461                         return inputValues.getBit(index);\r
 462                 }\r
 463 \r
 464                 /**\r
 465                  * @return A copy (safe to modify) of the values the {@link ReadEnd} is currently feeding into the associated {@link Wire}.\r
 466                  */\r
 467                 public BitVector getInputValues()\r
 468                 {\r
 469                         return getInputValues(0, length);\r
 470                 }\r
 471 \r
 472                 public BitVector getInputValues(int start, int end)\r
 473                 {\r
 474                         return inputValues.subVector(start, end);\r
 475                 }\r
 476 \r
 477                 /**\r
 478                  * {@link ReadEnd} now feeds Z into the associated {@link Wire}.\r
 479                  */\r
 480                 public void clearSignals()\r
 481                 {\r
 482                         feedSignals(Z.toVector(length));\r
 483                 }\r
 484 \r
 485                 public BitVector wireValuesExcludingMe()\r
 486                 {\r
 487                         BitVectorMutator mutator = BitVectorMutator.empty();\r
 488                         for (ReadWriteEnd wireEnd : inputs)\r
 489                         {\r
 490                                 if (wireEnd == this)\r
 491                                         continue;\r
 492                                 mutator.join(wireEnd.inputValues);\r
 493                         }\r
 494                         return mutator.toBitVector();\r
 495                 }\r
 496 \r
 497                 @Override\r
 498                 public String toString()\r
 499                 {\r
 500                         return inputValues.toString();\r
 501                 }\r
 502 \r
 503                 @Override\r
 504                 public void close()\r
 505                 {\r
 506                         super.close();\r
 507                         open = false;\r
 508                 }\r
 509 \r
 510                 void setWriting(boolean isWriting)\r
 511                 {\r
 512                         if (this.isWriting != isWriting)\r
 513                         {\r
 514                                 this.isWriting = isWriting;\r
 515                                 if (isWriting)\r
 516                                         inputs.add(this);\r
 517                                 else\r
 518                                         inputs.remove(this);\r
 519                                 Wire.this.recalculate();\r
 520                         }\r
 521                 }\r
 522 \r
 523                 boolean isWriting()\r
 524                 {\r
 525                         return isWriting;\r
 526                 }\r
 527         }\r
 528 \r
 529         @Override\r
 530         public String toString()\r
 531         {\r
 532                 String name = this.name == null ? String.format("0x%08x", hashCode()) : this.name;\r
 533                 return String.format("wire %s value: %s inputs: %s", name, values, inputs);\r
 534         }\r
 535 \r
 536         public static ReadEnd[] extractEnds(Wire[] w)\r
 537         {\r
 538                 ReadEnd[] inputs = new ReadEnd[w.length];\r
 539                 for (int i = 0; i < w.length; i++)\r
 540                         inputs[i] = w[i].createReadWriteEnd();\r
 541                 return inputs;\r
 542         }\r
 543 \r
 544         // TODO Fix ReadWriteEnd feeding signals to entire Wire (Z) instead of only selected Bits\r
 545         /**\r
 546          * Fuses the selected bits of two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning:\r
 547          * The bits are permanently fused together.\r
 548          * \r
 549          * @param a      The {@link Wire} to be (partially) fused with b\r
 550          * @param b      The {@link Wire} to be (partially) fused with a\r
 551          * @param fromA  The first bit of {@link Wire} a to be fused\r
 552          * @param fromB  The first bit of {@link Wire} b to be fused\r
 553          * @param length The amount of bits to fuse\r
 554          */\r
 555         public static void fuse(Wire a, Wire b, int fromA, int fromB, int length)\r
 556         {\r
 557                 ReadWriteEnd rA = a.createReadWriteEnd(), rB = b.createReadWriteEnd();\r
 558                 rA.setWriting(false);\r
 559                 rB.setWriting(false);\r
 560                 rA.setValues(BitVector.of(Bit.Z, a.length));\r
 561                 rB.setValues(BitVector.of(Bit.Z, b.length));\r
 562                 Fusion aF = new Fusion(rB, fromA, fromB, length), bF = new Fusion(rA, fromB, fromA, length);\r
 563                 rA.registerObserver(aF);\r
 564                 rB.registerObserver(bF);\r
 565                 aF.update(rA);\r
 566                 bF.update(rB);\r
 567         }\r
 568 \r
 569         /**\r
 570          * \r
 571          * Fuses two wires together. If the bits change in one Wire, the other is changed accordingly immediately. Warning: The bits are\r
 572          * permanently fused together.\r
 573          * \r
 574          * @param a The {@link Wire} to be fused with b\r
 575          * @param b The {@link Wire} to be fused with a\r
 576          */\r
 577         public static void fuse(Wire a, Wire b)\r
 578         {\r
 579                 fuse(a, b, 0, 0, a.length);\r
 580         }\r
 581 \r
 582         private static class Fusion implements LogicObserver\r
 583         {\r
 584                 private ReadWriteEnd target;\r
 585                 int fromSource, fromTarget, length;\r
 586 \r
 587                 public Fusion(ReadWriteEnd target, int fromSource, int fromTarget, int length)\r
 588                 {\r
 589                         this.target = target;\r
 590                         this.fromSource = fromSource;\r
 591                         this.fromTarget = fromTarget;\r
 592                         this.length = length;\r
 593                 }\r
 594 \r
 595                 @Override\r
 596                 public void update(LogicObservable initiator)\r
 597                 {\r
 598                         ReadWriteEnd source = (ReadWriteEnd) initiator;\r
 599                         if (source.getWire().inputs.size() - (source.isWriting() ? 1 : 0) == 0)\r
 600                                 target.setWriting(false);\r
 601                         else\r
 602                         {\r
 603                                 target.setWriting(true);\r
 604                                 BitVector targetInput = source.wireValuesExcludingMe().subVector(fromSource, fromSource + length);\r
 605                                 target.setValues(fromTarget, targetInput);\r
 606                         }\r
 607                 }\r
 608         }\r
 609 }