X-Git-Url: https://mograsim.net/gitweb/?a=blobdiff_plain;f=net.mograsim.logic.core%2Fsrc%2Fnet%2Fmograsim%2Flogic%2Fcore%2Ftypes%2FBitVector.java;h=74375210549cc280f52ec497ece927a76835df90;hb=4afd7c9afe4333815a488f90bdc3c3b9991028f4;hp=f92401f0e6fc0e2a0f7eea699a0ea4c99dfb43d3;hpb=f14ea37d69488dd51518a36413af7176916b8bd7;p=Mograsim.git

diff --git a/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java b/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java
index f92401f0..74375210 100644
--- a/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java
+++ b/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java
@@ -13,26 +13,46 @@ import java.util.function.UnaryOperator;
 /**
  * Immutable class representing a {@link Bit}Vector
  *
- *
  * @author Christian Femers
  *
  */
 public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit>, RandomAccess
 {
+	public static final BitVector SINGLE_U = new BitVector(Bit.U);
+	public static final BitVector SINGLE_X = new BitVector(Bit.X);
+	public static final BitVector SINGLE_0 = new BitVector(Bit.ZERO);
+	public static final BitVector SINGLE_1 = new BitVector(Bit.ONE);
+	public static final BitVector SINGLE_Z = new BitVector(Bit.Z);
+
+	private static final BitVector[] SINGLE_BIT_MAPPING = { SINGLE_U, SINGLE_X, SINGLE_0, SINGLE_1, SINGLE_Z };
+
 	private final Bit[] bits;
 
+	private BitVector(Bit single)
+	{
+		Objects.requireNonNull(single);
+		bits = new Bit[] { single };
+	}
+
 	private BitVector(Bit[] bits)
 	{
-		this.bits = Objects.requireNonNull(bits);
+		this.bits = Objects.requireNonNull(bits); // do this first to "catch" bits==null before the foreach loop
+		for (Bit bit : bits)
+			if (bit == null)
+				throw new NullPointerException();
 	}
 
 	public static BitVector of(Bit... bits)
 	{
+		if (bits.length == 1)
+			return SINGLE_BIT_MAPPING[bits[0].ordinal()];
 		return new BitVector(bits.clone());
 	}
 
 	public static BitVector of(Bit bit, int length)
 	{
+		if (length == 1)
+			return SINGLE_BIT_MAPPING[bit.ordinal()];
 		return new BitVector(bit.makeArray(length));
 	}
 
@@ -41,11 +61,22 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return BitVectorMutator.of(this);
 	}
 
-	public Bit getBit(int bitIndex)
+	/**
+	 * Returns the most significant bit at <code>bitIndex</code>. (leftmost bit of a binary number at the given index)
+	 */
+	public Bit getMSBit(int bitIndex)
 	{
 		return bits[bitIndex];
 	}
 
+	/**
+	 * Returns the least significant bit at <code>bitIndex</code>. (rightmost bit of a binary number at the given index)
+	 */
+	public Bit getLSBit(int bitIndex)
+	{
+		return bits[bits.length - bitIndex - 1];
+	}
+
 	public Bit[] getBits()
 	{
 		return bits.clone();
@@ -55,6 +86,8 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	public BitVector join(BitVector t)
 	{
 		checkCompatibility(t);
+		if (bits.length == 1)
+			return SINGLE_BIT_MAPPING[bits[0].join(t.bits[0]).ordinal()];
 		return new BitVector(binOp(bits.clone(), t.bits, Bit::join));
 	}
 
@@ -62,6 +95,8 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	public BitVector and(BitVector t)
 	{
 		checkCompatibility(t);
+		if (bits.length == 1)
+			return SINGLE_BIT_MAPPING[bits[0].and(t.bits[0]).ordinal()];
 		return new BitVector(binOp(bits.clone(), t.bits, Bit::and));
 	}
 
@@ -69,6 +104,8 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	public BitVector or(BitVector t)
 	{
 		checkCompatibility(t);
+		if (bits.length == 1)
+			return SINGLE_BIT_MAPPING[bits[0].or(t.bits[0]).ordinal()];
 		return new BitVector(binOp(bits.clone(), t.bits, Bit::or));
 	}
 
@@ -76,12 +113,16 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	public BitVector xor(BitVector t)
 	{
 		checkCompatibility(t);
+		if (bits.length == 1)
+			return SINGLE_BIT_MAPPING[bits[0].xor(t.bits[0]).ordinal()];
 		return new BitVector(binOp(bits.clone(), t.bits, Bit::xor));
 	}
 
 	@Override
 	public BitVector not()
 	{
+		if (bits.length == 1)
+			return SINGLE_BIT_MAPPING[bits[0].not().ordinal()];
 		return new BitVector(unOp(bits.clone(), Bit::not));
 	}
 
@@ -221,16 +262,38 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 			return this;
 		}
 
-		public void setBit(int bitIndex, Bit bit)
+		/**
+		 * Set the most significant bit at <code>bitIndex</code>. (leftmost bit of a binary number at the given index)
+		 */
+		public void setMSBit(int bitIndex, Bit bit)
 		{
 			bits[bitIndex] = bit;
 		}
 
-		public Bit getBit(int bitIndex)
+		/**
+		 * Set the least significant bit at <code>bitIndex</code>. (rightmost bit of a binary number at the given index)
+		 */
+		public void setLSBit(int bitIndex, Bit bit)
+		{
+			bits[bits.length - bitIndex - 1] = bit;
+		}
+
+		/**
+		 * Returns the most significant bit at <code>bitIndex</code>. (leftmost bit of a binary number at the given index)
+		 */
+		public Bit getMSBit(int bitIndex)
 		{
 			return bits[bitIndex];
 		}
 
+		/**
+		 * Returns the least significant bit at <code>bitIndex</code>. (rightmost bit of a binary number at the given index)
+		 */
+		public Bit getLSBit(int bitIndex)
+		{
+			return bits[bits.length - bitIndex - 1];
+		}
+
 		public int length()
 		{
 			return bits.length;
@@ -284,7 +347,7 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	}
 
 	/**
-	 * All {@link Bit}s symbols concatenated together
+	 * All {@link Bit}s symbols concatenated together (MSB first)
 	 * 
 	 * @see #parse(String)
 	 */
@@ -298,7 +361,7 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	}
 
 	/**
-	 * Parses a String containing solely {@link Bit} symbols
+	 * Parses a String containing solely {@link Bit} symbols (MSB first)
 	 * 
 	 * @see #toString()
 	 */
@@ -312,6 +375,9 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return new BitVector(values);
 	}
 
+	/**
+	 * Iterate over the {@link Bit}s of the BitVector <b>from MSB to LSB</b> (left to right).
+	 */
 	@Override
 	public Iterator<Bit> iterator()
 	{
@@ -324,7 +390,7 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 			{
 				if (!hasNext())
 					throw new NoSuchElementException();
-				return getBit(pos++);
+				return getMSBit(pos++);
 			}
 
 			@Override