1 package era.mi.logic.wires;
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3 import java.io.Closeable;
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4 import java.util.ArrayList;
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5 import java.util.Arrays;
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6 import java.util.Iterator;
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7 import java.util.List;
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9 import era.mi.logic.Bit;
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10 import era.mi.logic.Simulation;
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11 import era.mi.logic.Util;
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14 * Represents an array of wires that can store n bits of information.
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16 * @author Fabian Stemmler
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19 public class WireArray
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21 private Bit[] values;
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22 public final int travelTime;
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23 private List<WireArrayObserver> observers = new ArrayList<WireArrayObserver>();
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24 public final int length;
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25 private List<WireArrayEnd> inputs = new ArrayList<WireArrayEnd>();
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27 public WireArray(int length, int travelTime)
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30 throw new IllegalArgumentException(
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31 String.format("Tried to create an array of wires with length %d, but a length of less than 1 makes no sense.", length));
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32 this.length = length;
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33 this.travelTime = travelTime;
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37 private void initValues()
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39 values = Bit.U.makeArray(length);
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42 private void recalculateSingleInput()
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44 WireArrayEnd input = inputs.get(0);
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45 if (!Arrays.equals(input.getValues(), values))
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47 Bit[] oldValues = values.clone();
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48 System.arraycopy(input.getValues(), 0, values, 0, length);
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49 notifyObservers(oldValues);
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53 private void recalculateMultipleInputs()
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55 Iterator<WireArrayEnd> it = inputs.iterator();
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56 Bit[] newValues = it.next().inputValues.clone();
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58 while (it.hasNext())
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60 WireArrayEnd input = it.next();
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61 Bit[] bits = input.getValues();
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62 for (int i = 0; i < length; i++)
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64 if (Bit.Z.equals(bits[i]) || newValues[i].equals(bits[i]))
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66 else if (Bit.Z.equals(newValues[i]))
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67 newValues[i] = bits[i];
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69 newValues[i] = Bit.X;
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73 if (!Arrays.equals(newValues, values))
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75 Bit[] oldValues = values;
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77 notifyObservers(oldValues);
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81 private void recalculate()
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83 switch (inputs.size())
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88 recalculateSingleInput();
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91 recalculateMultipleInputs();
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96 * The WireArray is interpreted as an unsigned integer with n bits.
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98 * @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
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99 * value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
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101 * @author Fabian Stemmler
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103 public boolean hasNumericValue()
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105 for (Bit b : values)
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107 if (b != Bit.ZERO && b != Bit.ONE)
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114 * The WireArray is interpreted as an unsigned integer with n bits.
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116 * @return The unsigned value of the {@link WireArray}'s bits, where value 0 corresponds with 2^0, value 1 is 2^1 and so on.
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118 * @author Fabian Stemmler
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120 public long getUnsignedValue()
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124 for (int i = 0; i < length; i++)
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131 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;
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144 * The WireArray is interpreted as a signed integer with n bits.
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146 * @return The signed value of the {@link WireArray}'s bits, where value 0 corresponds with 2^0, value 1 is 2^1 and so on.
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148 * @author Fabian Stemmler
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150 public long getSignedValue()
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152 long val = getUnsignedValue();
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153 long mask = 1 << (length - 1);
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154 if ((mask & val) != 0)
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156 int shifts = 64 - length;
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157 return (val << shifts) >> shifts;
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163 * Included for convenient use on {@link WireArray}s of length 1.
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165 * @return The value of bit 0.
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167 * @author Fabian Stemmler
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169 public Bit getValue()
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171 return getValue(0);
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176 * @param index Index of the requested bit.
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177 * @return The value of the indexed bit.
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179 * @author Fabian Stemmler
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181 public Bit getValue(int index)
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183 return values[index];
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186 public Bit[] getValues(int start, int end)
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188 int length = end - start;
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189 Bit[] bits = new Bit[length];
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190 System.arraycopy(values, start, bits, 0, length);
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195 * @return An array of length n containing the values of the n bits in the {@link WireArray}. Can be safely modified.
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197 * @author Fabian Stemmler
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199 public Bit[] getValues()
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201 return values.clone();
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205 * Adds an {@link WireArrayObserver}, who will be notified when the value of the {@link WireArray} is updated.
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207 * @param ob The {@link WireArrayObserver} to be notified of changes.
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208 * @return true if the given {@link WireArrayObserver} was not already registered, false otherwise
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210 * @author Fabian Stemmler
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212 public boolean addObserver(WireArrayObserver ob)
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214 return observers.add(ob);
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217 private void notifyObservers(Bit[] oldValues)
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219 for (WireArrayObserver o : observers)
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220 o.update(this, oldValues);
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224 * Create and register a {@link WireArrayEnd} object, which is tied to this {@link WireArray}.
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226 public WireArrayEnd createInput()
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228 return new WireArrayEnd(this);
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231 private void registerInput(WireArrayEnd toRegister)
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233 inputs.add(toRegister);
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237 * A {@link WireArrayEnd} feeds a constant signal into the {@link WireArray} it is tied to. The combination of all inputs determines the
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238 * {@link WireArray}s final value. X dominates all other inputs Z does not affect the final value, unless there are no other inputs than
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239 * Z 0 and 1 turn into X when they are mixed
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241 * @author Fabian Stemmler
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243 public class WireArrayEnd implements Closeable
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245 public final WireArray owner;
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246 private boolean open;
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247 private Bit[] inputValues;
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249 private WireArrayEnd(WireArray owner)
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252 this.owner = owner;
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255 owner.registerInput(this);
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258 private void initValues()
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260 inputValues = Bit.Z.makeArray(length);
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264 * Sets the wires values. This takes up time, as specified by the {@link WireArray}s travel time.
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266 * @param newValues The new values the wires should take on.
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268 * @author Fabian Stemmler
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270 public void feedSignals(Bit... newValues)
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272 if (newValues.length == length)
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274 feedSignals(0, newValues);
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276 throw new IllegalArgumentException(
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277 String.format("Attempted to input %d bits instead of %d bits.", newValues.length, length));
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281 * Sets values of a subarray of wires. This takes up time, as specified by the {@link WireArray}s travel time.
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283 * @param newValues The new values the wires should take on.
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284 * @param startingBit The first index of the subarray of wires.
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286 * @author Fabian Stemmler
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288 public void feedSignals(int startingBit, Bit... newValues)
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291 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
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292 Simulation.TIMELINE.addEvent((e) -> setValues(startingBit, newValues), travelTime);
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295 private void setValues(int startingBit, Bit... newValues)
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297 int exclLastIndex = startingBit + newValues.length;
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298 if (length < exclLastIndex)
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299 throw new ArrayIndexOutOfBoundsException(
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300 String.format("Attempted to input bits from index %d to %d when there are only %d wires.", startingBit,
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301 exclLastIndex - 1, length));
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302 if (!Arrays.equals(inputValues, startingBit, exclLastIndex, newValues, 0, newValues.length))
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304 System.arraycopy(newValues, 0, inputValues, startingBit, newValues.length);
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305 owner.recalculate();
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310 * Returns a copy (safe to modify) of the values the {@link WireArrayEnd} is currently feeding into the associated
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311 * {@link WireArray}.
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313 public Bit[] getValues()
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315 return inputValues.clone();
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319 * {@link WireArrayEnd} now feeds Z into the associated {@link WireArray}.
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321 public void clearSignals()
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323 feedSignals(Bit.Z.makeArray(length));
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326 public Bit[] wireValuesExcludingMe()
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328 Bit[] bits = Bit.Z.makeArray(length);
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329 for (WireArrayEnd wai : inputs)
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333 Util.combineInto(bits, wai.getValues());
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338 public Bit getWireValue()
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340 return owner.getValue();
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343 public Bit[] getWireValues()
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345 return owner.getValues();
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349 public String toString()
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351 return Arrays.toString(inputValues);
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355 public void close()
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357 inputs.remove(this);
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363 public String toString()
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365 return String.format("wire 0x%08x value: %s inputs: %s", hashCode(), Arrays.toString(values), inputs);
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368 public static WireArrayEnd[] extractInputs(WireArray[] w)
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370 WireArrayEnd[] inputs = new WireArrayEnd[w.length];
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371 for (int i = 0; i < w.length; i++)
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372 inputs[i] = w[i].createInput();
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