X-Git-Url: https://mograsim.net/gitweb/?a=blobdiff_plain;f=era.mi%2Fsrc%2Fmograsim%2Flogic%2Fcore%2Ftypes%2FBit.java;fp=era.mi%2Fsrc%2Fmograsim%2Flogic%2Fcore%2Ftypes%2FBit.java;h=60c4e192b971ac328279a6fc519c2330eb10b355;hb=a28f7aa0dab4248e99159c5a647676170cb17a4e;hp=0000000000000000000000000000000000000000;hpb=80bfbd8ebf0ad8a7ad98584544a0c73f43e6f3b6;p=Mograsim.git

diff --git a/era.mi/src/mograsim/logic/core/types/Bit.java b/era.mi/src/mograsim/logic/core/types/Bit.java
new file mode 100644
index 00000000..60c4e192
--- /dev/null
+++ b/era.mi/src/mograsim/logic/core/types/Bit.java
@@ -0,0 +1,132 @@
+package mograsim.logic.core.types;
+
+import java.util.Arrays;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * stdlogic according to IEEE 1164
+ */
+public enum Bit implements StrictLogicType<Bit>
+{
+	U("U"), X("X"), ZERO("0"), ONE("1"), Z("Z");
+
+	private final String symbol;
+
+	private Bit(String symbol)
+	{
+		this.symbol = symbol;
+	}
+
+	@Override
+	public Bit and(Bit other)
+	{
+		return fromTable(AND_TABLE, this, other);
+	}
+
+	@Override
+	public Bit or(Bit other)
+	{
+		return fromTable(OR_TABLE, this, other);
+	}
+
+	@Override
+	public Bit xor(Bit other)
+	{
+		return fromTable(XOR_TABLE, this, other);
+	}
+
+	@Override
+	public Bit not()
+	{
+		switch (this)
+		{
+		case U:
+			return U;
+		case ONE:
+			return ZERO;
+		case ZERO:
+			return ONE;
+		default:
+			return X;
+		}
+	}
+
+	public Bit[] makeArray(int length)
+	{
+		Bit[] bits = new Bit[length];
+		Arrays.fill(bits, this);
+		return bits;
+	}
+
+	public BitVector toVector(int length)
+	{
+		return BitVector.of(this, length);
+	}
+
+	@Override
+	public Bit join(Bit other)
+	{
+		return fromTable(JOIN_TABLE, this, other);
+	}
+
+	@Override
+	public String toString()
+	{
+		return getSymbol();
+	}
+
+	public String getSymbol()
+	{
+		return symbol;
+	}
+
+	public static Bit parse(String s)
+	{
+		Bit bit = SYMBOL_MAP.get(s);
+		Objects.requireNonNull(bit, "No Bit found for symbol " + s);
+		return bit;
+	}
+
+	public static Bit parse(String s, int symbolPosition)
+	{
+		return parse(s.substring(symbolPosition, symbolPosition + 1));
+	}
+
+	private static Bit fromTable(Bit[][] table, Bit a, Bit b)
+	{
+		return table[a.ordinal()][b.ordinal()];
+	}
+
+	static final Map<String, Bit> SYMBOL_MAP = Map.of(U.symbol, U, X.symbol, X, ZERO.symbol, ZERO, ONE.symbol, ONE, Z.symbol, Z);
+
+	// @formatter:off
+	private static final Bit[][] JOIN_TABLE = 
+		{ { U, U, U,    U,   U    }, 
+		  { U, X, X,    X,   X    }, 
+		  { U, X, ZERO, X,   ZERO },
+		  { U, X, X,    ONE, ONE  }, 
+		  { U, X, ZERO, ONE, Z    } };
+
+	private static final Bit[][] AND_TABLE = 
+		{ { U,    U,    ZERO, U,    U    }, 
+		  { U,    X,    ZERO, X,    X    },
+		  { ZERO, ZERO, ZERO, ZERO, ZERO }, 
+		  { U,    X,    ZERO, ONE,  X    }, 
+		  { U,    X,    ZERO, X,    X    } };
+
+	private static final Bit[][] OR_TABLE =
+    	{ { U,   U,   U,    ONE, U    },    
+    	  { U,   X,   X,    ONE, X    },    
+    	  { U,   X,   ZERO, ONE, X    },    
+    	  { ONE, ONE, ONE,  ONE, ONE  },    
+    	  { U,   X,   X,    ONE, X    } };
+	
+	private static final Bit[][] XOR_TABLE =
+    	{ { U, U, U,    U,    U },    
+    	  { U, X, X,    X,    X },    
+    	  { U, X, ZERO, ONE,  X },    
+    	  { U, X, ONE,  ZERO, X },    
+    	  { U, X, X,    X,    X } }; 
+	// @formatter:on
+}
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