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