import era.mi.logic.Bit;
import era.mi.logic.Simulation;
+import era.mi.logic.Util;
/**
* Represents an array of wires that can store n bits of information.
+ *
* @author Fabian Stemmler
*
*/
-public class WireArray
-{
+public class WireArray {
private Bit[] values;
public final int travelTime;
private List<WireArrayObserver> observers = new ArrayList<WireArrayObserver>();
public final int length;
private List<WireArrayInput> inputs = new ArrayList<WireArrayInput>();
-
- public WireArray(int length, int travelTime)
- {
- if(length < 1)
- throw new IllegalArgumentException("Tried to create an array of wires with length " + length + ", but a length of less than 1 makes no sense.");
+
+ public WireArray(int length, int travelTime) {
+ if (length < 1)
+ throw new IllegalArgumentException(
+ String.format("Tried to create an array of wires with length %d, but a length of less than 1 makes no sense.", length));
this.length = length;
this.travelTime = travelTime;
initValues();
}
-
- private void initValues()
- {
- values = new Bit[length];
- for(int i = 0; i < length; i++)
- values[i] = Bit.Z;
+
+ private void initValues() {
+ values = Bit.Z.makeArray(length);
}
-
- private void recalculateSingleInput()
- {
+
+ private void recalculateSingleInput() {
WireArrayInput input = inputs.get(0);
- if(!Arrays.equals(input.getValues(), values))
- {
+ if (!Arrays.equals(input.getValues(), values)) {
+ Bit[] oldValues = values.clone();
System.arraycopy(input.getValues(), 0, values, 0, length);
- notifyObservers();
+ notifyObservers(oldValues);
}
}
-
- private void recalculateMultipleInputs()
- {
+
+ private void recalculateMultipleInputs() {
Iterator<WireArrayInput> it = inputs.iterator();
- Bit[] newValues = it.next().values.clone();
-
- while(it.hasNext())
- {
+ Bit[] newValues = it.next().inputValues.clone();
+
+ while (it.hasNext()) {
WireArrayInput input = it.next();
Bit[] bits = input.getValues();
- for(int i = 0; i < length; i++)
- {
- if(Bit.Z.equals(bits[i]) || newValues[i].equals(bits[i]))
+ for (int i = 0; i < length; i++) {
+ if (Bit.Z.equals(bits[i]) || newValues[i].equals(bits[i]))
continue;
- else if(Bit.Z.equals(newValues[i]))
+ else if (Bit.Z.equals(newValues[i]))
newValues[i] = bits[i];
else
newValues[i] = Bit.X;
}
}
-
- if(!Arrays.equals(newValues, values))
- {
- notifyObservers();
+
+ if (!Arrays.equals(newValues, values)) {
+ Bit[] oldValues = values;
values = newValues;
+ notifyObservers(oldValues);
}
}
- private void recalculate()
- {
- switch(inputs.size())
- {
+ private void recalculate() {
+ switch (inputs.size()) {
case 0:
return;
case 1:
recalculateMultipleInputs();
}
}
-
+
/**
* The WireArray is interpreted as an unsigned integer with n bits.
- * @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 value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
+ *
+ * @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
+ * value), not <code>Bit.X</code> or <code>Bit.Z</code>. <code>false</code> is returned otherwise.
*
* @author Fabian Stemmler
*/
- public boolean hasNumericValue()
- {
- for(Bit b : values)
- {
- if(b != Bit.ZERO && b != Bit.ONE)
+ public boolean hasNumericValue() {
+ for (Bit b : values) {
+ if (b != Bit.ZERO && b != Bit.ONE)
return false;
}
return true;
}
-
+
/**
* The WireArray is interpreted as an unsigned integer with n bits.
+ *
* @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.
*
* @author Fabian Stemmler
*/
- public long getUnsignedValue()
- {
+ public long getUnsignedValue() {
long val = 0;
long mask = 1;
- for(int i = 0; i < length; i++)
- {
- switch(values[i])
- {
+ for (int i = 0; i < length; i++) {
+ switch (values[i]) {
default:
case Z:
case X:
- return 0; //TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0; Random number?
+ return 0; // TODO: Proper handling for getUnsignedValue(), if not all bits are 1 or 0;
+ // Random number?
case ONE:
val |= mask;
break;
}
return val;
}
-
+
/**
* The WireArray is interpreted as a signed integer with n bits.
+ *
* @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.
*
* @author Fabian Stemmler
*/
- public long getSignedValue()
- {
+ public long getSignedValue() {
long val = getUnsignedValue();
long mask = 1 << (length - 1);
- if((mask & val) != 0)
- {
+ if ((mask & val) != 0) {
int shifts = 64 - length;
return (val << shifts) >> shifts;
}
return val;
}
-
+
/**
* Included for convenient use on {@link WireArray}s of length 1.
+ *
* @return The value of bit 0.
*
* @author Fabian Stemmler
*/
- public Bit getValue()
- {
+ public Bit getValue() {
return getValue(0);
}
-
+
/**
*
* @param index Index of the requested bit.
*
* @author Fabian Stemmler
*/
- public Bit getValue(int index)
- {
+ public Bit getValue(int index) {
return values[index];
}
-
- public Bit[] getValues(int start, int end)
- {
+
+ public Bit[] getValues(int start, int end) {
int length = end - start;
Bit[] bits = new Bit[length];
- System.arraycopy(values, start, bits, 0, length);
+ System.arraycopy(values, start, bits, 0, length);
return bits;
}
-
-
+
/**
* @return An array of length n containing the values of the n bits in the {@link WireArray}. Can be safely modified.
*
* @author Fabian Stemmler
*/
- public Bit[] getValues()
- {
+ public Bit[] getValues() {
return values.clone();
}
-
+
/**
* Adds an {@link WireArrayObserver}, who will be notified when the value of the {@link WireArray} is updated.
+ *
* @param ob The {@link WireArrayObserver} to be notified of changes.
* @return true if the given {@link WireArrayObserver} was not already registered, false otherwise
*
* @author Fabian Stemmler
*/
- public boolean addObserver(WireArrayObserver ob)
- {
+ public boolean addObserver(WireArrayObserver ob) {
return observers.add(ob);
}
-
- private void notifyObservers()
- {
- for(WireArrayObserver o : observers)
- o.update(this);
+
+ private void notifyObservers(Bit[] oldValues) {
+ for (WireArrayObserver o : observers)
+ o.update(this, oldValues);
}
-
- public WireArrayInput createInput()
- {
+
+ /**
+ * Create and register a {@link WireArrayInput} object, which is tied to this {@link WireArray}.
+ */
+ public WireArrayInput createInput() {
return new WireArrayInput(this);
}
-
- private void registerInput(WireArrayInput toRegister)
- {
+
+ private void registerInput(WireArrayInput toRegister) {
inputs.add(toRegister);
}
-
+
+ /**
+ * A {@link WireArrayInput} feeds a constant signal into the {@link WireArray} it is tied to. The combination of all inputs determines
+ * the {@link WireArray}s final value. X dominates all other inputs Z does not affect the final value, unless there are no other inputs
+ * than Z 0 and 1 turn into X when they are mixed
+ *
+ * @author Fabian Stemmler
+ */
public class WireArrayInput {
public final WireArray owner;
- private Bit[] values;
-
+ private Bit[] inputValues;
+
private WireArrayInput(WireArray owner) {
super();
this.owner = owner;
initValues();
owner.registerInput(this);
}
-
- private void initValues()
- {
- values = new Bit[length];
- for(int i = 0; i < length; i++)
- values[i] = Bit.Z;
+
+ private void initValues() {
+ inputValues = Bit.Z.makeArray(length);
}
-
+
/**
* Sets the wires values. This takes up time, as specified by the {@link WireArray}s travel time.
+ *
* @param newValues The new values the wires should take on.
*
* @author Fabian Stemmler
*/
- public void feedSignals(Bit... newValues)
- {
- if(newValues.length == length)
- {
+ public void feedSignals(Bit... newValues) {
+ if (newValues.length == length) {
feedSignals(0, newValues);
- }
- else
- throw new IllegalArgumentException("Attempted to input " + newValues.length + " bits instead of " + length + " bits.");
+ } else
+ throw new IllegalArgumentException(
+ String.format("Attempted to input %o bits instead of %o bits.", newValues.length, length));
}
-
+
/**
* Sets values of a subarray of wires. This takes up time, as specified by the {@link WireArray}s travel time.
- * @param newValues The new values the wires should take on.
+ *
+ * @param newValues The new values the wires should take on.
* @param startingBit The first index of the subarray of wires.
*
* @author Fabian Stemmler
*/
- public void feedSignals(int startingBit, Bit... newValues)
- {
+ public void feedSignals(int startingBit, Bit... newValues) {
Simulation.TIMELINE.addEvent((e) -> setValues(startingBit, newValues), travelTime);
}
-
- private void setValues(int startingBit, Bit... newValues)
- {
+
+ private void setValues(int startingBit, Bit... newValues) {
int exclLastIndex = startingBit + newValues.length;
- if(length < exclLastIndex)
- throw new ArrayIndexOutOfBoundsException("Attempted to input bits from index " + startingBit + " to "
- + exclLastIndex + " when there are only " + length + "wires.");
- if(!Arrays.equals(values, startingBit, exclLastIndex, newValues, 0, newValues.length))
- {
- System.arraycopy(newValues, 0, values, startingBit, newValues.length);
+ if (length < exclLastIndex)
+ throw new ArrayIndexOutOfBoundsException(
+ String.format("Attempted to input bits from index %o to %o when there are only %o wires.", startingBit,
+ exclLastIndex - 1, length));
+ if (!Arrays.equals(inputValues, startingBit, exclLastIndex, newValues, 0, newValues.length)) {
+ System.arraycopy(newValues, 0, inputValues, startingBit, newValues.length);
owner.recalculate();
}
}
-
- public Bit[] getValues()
- {
- return values.clone();
+
+ /**
+ * Returns a copy (safe to modify) of the values the {@link WireArrayInput} is currently feeding into the associated
+ * {@link WireArray}.
+ */
+ public Bit[] getValues() {
+ return inputValues.clone();
+ }
+
+ /**
+ * {@link WireArrayInput} now feeds Z into the associated {@link WireArray}.
+ */
+ public void clearSignals() {
+ feedSignals(Bit.Z.makeArray(length));
}
-
- public void clearSignals()
- {
- Bit[] bits = new Bit[length];
- for(int i = 0; i < length; i++)
- bits[i] = Bit.Z;
- feedSignals(bits);
+
+ public Bit[] wireValuesExcludingMe() {
+ Bit[] bits = Bit.Z.makeArray(length);
+ for (WireArrayInput wai : inputs) {
+ if (wai == this)
+ continue;
+ Util.combineInto(bits, wai.getValues());
+ }
+ return bits;
}
-
+
@Override
- public String toString()
- {
- return Arrays.toString(values);
+ public String toString() {
+ return Arrays.toString(inputValues);
}
}
@Override
- public String toString()
- {
+ public String toString() {
return String.format("wire 0x%08x value: %s inputs: %s", hashCode(), Arrays.toString(values), inputs);
}
-}
+
+ public static WireArrayInput[] extractInputs(WireArray[] w) {
+ WireArrayInput[] inputs = new WireArrayInput[w.length];
+ for (int i = 0; i < w.length; i++)
+ inputs[i] = w[i].createInput();
+ return inputs;
+ }
+}
\ No newline at end of file