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 newValues[i] = newValues[i].combineWith(bits[i]);
68 if (!Arrays.equals(newValues, values))
70 Bit[] oldValues = values;
72 notifyObservers(oldValues);
76 private void recalculate()
78 switch (inputs.size())
83 recalculateSingleInput();
86 recalculateMultipleInputs();
91 * The WireArray is interpreted as an unsigned integer with n bits.
93 * @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
94 * value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
96 * @author Fabian Stemmler
98 public boolean hasNumericValue()
102 if (b != Bit.ZERO && b != Bit.ONE)
109 * The WireArray is interpreted as an unsigned integer with n bits.
111 * @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.
113 * @author Fabian Stemmler
115 public long getUnsignedValue()
119 for (int i = 0; i < length; i++)
126 return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;
139 * The WireArray is interpreted as a signed integer with n bits.
141 * @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.
143 * @author Fabian Stemmler
145 public long getSignedValue()
147 long val = getUnsignedValue();
148 long mask = 1 << (length - 1);
149 if ((mask & val) != 0)
151 int shifts = 64 - length;
152 return (val << shifts) >> shifts;
158 * Included for convenient use on {@link WireArray}s of length 1.
160 * @return The value of bit 0.
162 * @author Fabian Stemmler
164 public Bit getValue()
171 * @param index Index of the requested bit.
172 * @return The value of the indexed bit.
174 * @author Fabian Stemmler
176 public Bit getValue(int index)
178 return values[index];
181 public Bit[] getValues(int start, int end)
183 int length = end - start;
184 Bit[] bits = new Bit[length];
185 System.arraycopy(values, start, bits, 0, length);
190 * @return An array of length n containing the values of the n bits in the {@link WireArray}. Can be safely modified.
192 * @author Fabian Stemmler
194 public Bit[] getValues()
196 return values.clone();
200 * Adds an {@link WireArrayObserver}, who will be notified when the value of the {@link WireArray} is updated.
202 * @param ob The {@link WireArrayObserver} to be notified of changes.
203 * @return true if the given {@link WireArrayObserver} was not already registered, false otherwise
205 * @author Fabian Stemmler
207 public boolean addObserver(WireArrayObserver ob)
209 return observers.add(ob);
212 private void notifyObservers(Bit[] oldValues)
214 for (WireArrayObserver o : observers)
215 o.update(this, oldValues);
219 * Create and register a {@link WireArrayEnd} object, which is tied to this {@link WireArray}.
221 public WireArrayEnd createInput()
223 return new WireArrayEnd(this);
226 private void registerInput(WireArrayEnd toRegister)
228 inputs.add(toRegister);
232 * A {@link WireArrayEnd} feeds a constant signal into the {@link WireArray} it is tied to. The combination of all inputs determines the
233 * {@link WireArray}s final value. X dominates all other inputs Z does not affect the final value, unless there are no other inputs than
234 * Z 0 and 1 turn into X when they are mixed
236 * @author Fabian Stemmler
238 public class WireArrayEnd implements Closeable
240 public final WireArray owner;
241 private boolean open;
242 private Bit[] inputValues;
244 private WireArrayEnd(WireArray owner)
250 owner.registerInput(this);
253 private void initValues()
255 inputValues = Bit.U.makeArray(length);
259 * Sets the wires values. This takes up time, as specified by the {@link WireArray}s travel time.
261 * @param newValues The new values the wires should take on.
263 * @author Fabian Stemmler
265 public void feedSignals(Bit... newValues)
267 if (newValues.length == length)
269 feedSignals(0, newValues);
271 throw new IllegalArgumentException(
272 String.format("Attempted to input %d bits instead of %d bits.", newValues.length, length));
276 * Sets values of a subarray of wires. This takes up time, as specified by the {@link WireArray}s travel time.
278 * @param newValues The new values the wires should take on.
279 * @param startingBit The first index of the subarray of wires.
281 * @author Fabian Stemmler
283 public void feedSignals(int startingBit, Bit... newValues)
286 throw new RuntimeException("Attempted to write to closed WireArrayEnd.");
287 Simulation.TIMELINE.addEvent((e) -> setValues(startingBit, newValues), travelTime);
290 private void setValues(int startingBit, Bit... newValues)
292 int exclLastIndex = startingBit + newValues.length;
293 if (length < exclLastIndex)
294 throw new ArrayIndexOutOfBoundsException(
295 String.format("Attempted to input bits from index %d to %d when there are only %d wires.", startingBit,
296 exclLastIndex - 1, length));
297 if (!Arrays.equals(inputValues, startingBit, exclLastIndex, newValues, 0, newValues.length))
299 System.arraycopy(newValues, 0, inputValues, startingBit, newValues.length);
305 * Returns a copy (safe to modify) of the values the {@link WireArrayEnd} is currently feeding into the associated
308 public Bit[] getValues()
310 return inputValues.clone();
314 * {@link WireArrayEnd} now feeds Z into the associated {@link WireArray}.
316 public void clearSignals()
318 feedSignals(Bit.Z.makeArray(length));
321 public Bit[] wireValuesExcludingMe()
323 Bit[] bits = Bit.Z.makeArray(length);
324 for (WireArrayEnd wai : inputs)
328 Util.combineInto(bits, wai.getValues());
333 public Bit getWireValue()
335 return owner.getValue();
338 public Bit[] getWireValues()
340 return owner.getValues();
344 public String toString()
346 return Arrays.toString(inputValues);
358 public String toString()
360 return String.format("wire 0x%08x value: %s inputs: %s", hashCode(), Arrays.toString(values), inputs);
363 public static WireArrayEnd[] extractInputs(WireArray[] w)
365 WireArrayEnd[] inputs = new WireArrayEnd[w.length];
366 for (int i = 0; i < w.length; i++)
367 inputs[i] = w[i].createInput();