X-Git-Url: https://mograsim.net/gitweb/?a=blobdiff_plain;f=era.mi%2Fsrc%2Fera%2Fmi%2Flogic%2FBit.java;h=804ecc94824a6b74c04aac8bee6a0b1fc4abce8f;hb=7f37c7b2431309e49a0ee116d1ee6c173272e926;hp=b18c5974f9d576442eb2e13256654fbf23dc8f1b;hpb=ebe86d1517aea138ffb6485b7bd2dff31fdb1253;p=Mograsim.git

diff --git a/era.mi/src/era/mi/logic/Bit.java b/era.mi/src/era/mi/logic/Bit.java
index b18c5974..804ecc94 100644
--- a/era.mi/src/era/mi/logic/Bit.java
+++ b/era.mi/src/era/mi/logic/Bit.java
@@ -1,62 +1,106 @@
 package era.mi.logic;
 
+import java.util.Arrays;
 
 public enum Bit
 {
 	ONE, ZERO, Z, X;
-	
+
 	public static Bit and(Bit a, Bit b)
 	{
 		return a.and(b);
 	}
-	
+
 	public Bit and(Bit other)
 	{
-		if(equals(Bit.ZERO) || other.equals(Bit.ZERO))
+		if (equals(Bit.ZERO) || other.equals(Bit.ZERO))
 			return Bit.ZERO;
-		else if(equals(other) && equals(Bit.ONE))
+		else if (equals(other) && equals(Bit.ONE))
 			return Bit.ONE;
 		else
 			return Bit.X;
 	}
-	
+
 	public static Bit or(Bit a, Bit b)
 	{
 		return a.or(b);
 	}
-	
+
 	public Bit or(Bit other)
 	{
-		if(equals(Bit.ONE) || other.equals(Bit.ONE))
+		if (equals(Bit.ONE) || other.equals(Bit.ONE))
 			return Bit.ONE;
-		else if(equals(other) && equals(Bit.ZERO))
+		else if (equals(other) && equals(Bit.ZERO))
 			return Bit.ZERO;
 		else
 			return Bit.X;
 	}
-	
+
 	public static Bit xor(Bit a, Bit b)
 	{
 		return a.xor(b);
 	}
-	
+
 	public Bit xor(Bit other)
 	{
-		//I'm uncertain how this should behave for cases where one value is neither 1 nor 0.
-		//TODO: Implement xor
-		return Bit.X;
+		if(this == Bit.X || this == Bit.Z
+				|| other == Bit.X || other == Bit.Z)
+			return Bit.X;
+		else
+			return this == other ? Bit.ZERO : Bit.ONE;
+	}
+
+	public Bit not()
+	{
+		switch (this)
+			{
+			case ONE:
+				return Bit.ZERO;
+			case ZERO:
+				return Bit.ONE;
+			default:
+				return Bit.X;
+			}
 	}
 	
-	public Bit not()
+	public Bit[] makeArray(int length)
 	{
-		switch(this)
-		{
-		case ONE:
-			return Bit.ZERO;
-		case ZERO:
-			return Bit.ONE;
-		default:
-			return Bit.X;
-		}
+		Bit[] bits = new Bit[length];
+		Arrays.fill(bits, this);
+		return bits;
+	}
+
+	/**
+	 * Rules for two bits that get directly connected<br>
+	 * <code><table>
+	 * <tbody>
+	 * <tr><td><td>X<td>0<td>1<td>Z</tr>
+	 * <tr><td>X<td>X<td>X<td>X<td>X</tr>
+	 * <tr><td>0<td>X<td>0<td>X<td>0</tr>
+	 * <tr><td>1<td>X<td>X<td>1<td>1</tr>
+	 * <tr><td>Z<td>X<td>0<td>1<td>Z</tr>
+	 * </tbody>
+	 * </table><code>
+	 * 
+	 * @return the result according to the table
+	 * 
+	 * @author Christian Femers
+	 */
+	public Bit combineWith(Bit other)
+	{
+		if (this == other)
+			return this;
+		if (this == X || other == X)
+			return X;
+		if (other == Z)
+			return this;
+		if (this == Z)
+			return other;
+		return X;
+	}
+
+	public static Bit combine(Bit a, Bit b)
+	{
+		return a.combineWith(b);
 	}
 }