added d-flipflop detection to DetermineJKStateMachine.java

hneemann · Jul 12, 2016 · 2e6f4fe · 2e6f4fe
1 parent edd1b8e
commit 2e6f4fe
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Showing 2 changed files with 27 additions and 7 deletions.
diff --git a/src/main/java/de/neemann/digital/analyse/DetermineJKStateMachine.java b/src/main/java/de/neemann/digital/analyse/DetermineJKStateMachine.java
@@ -1,9 +1,6 @@
 package de.neemann.digital.analyse;
 
-import de.neemann.digital.analyse.expression.Constant;
-import de.neemann.digital.analyse.expression.Expression;
-import de.neemann.digital.analyse.expression.ExpressionException;
-import de.neemann.digital.analyse.expression.Operation;
+import de.neemann.digital.analyse.expression.*;
 import de.neemann.digital.analyse.expression.format.FormatToExpression;
 import de.neemann.digital.analyse.expression.format.FormatterException;
 import de.neemann.digital.lang.Lang;
@@ -23,6 +20,7 @@
 public class DetermineJKStateMachine {
     private Expression j = null;
     private Expression nk = null;
+    private boolean isDFF;
 
     /**
      * Creates a new instance
@@ -33,7 +31,7 @@ public class DetermineJKStateMachine {
      * @throws FormatterException  FormatterException
      */
     public DetermineJKStateMachine(String name, Expression e) throws ExpressionException, FormatterException {
-        String notName = "¬" + name;
+        String notName = FormatToExpression.FORMATTER_UNICODE.format(Not.not(new Variable(name)));
 
         boolean wasK = false;
         boolean wasJ = false;
@@ -77,6 +75,7 @@ public DetermineJKStateMachine(String name, Expression e) throws ExpressionExcep
             if (wasK) nk = Constant.ONE;
             else nk = Constant.ZERO;
         }
+        isDFF = !wasJ && !wasK;
     }
 
     private Iterable<Expression> getOrs(Expression e) {
@@ -114,6 +113,16 @@ public Expression getK() {
         return not(nk);
     }
 
+    /**
+     * Returns true if it is logical a D flipflop.
+     * This means that K = not(J).
+     *
+     * @return true if it is logical a D flipflop
+     */
+    public boolean isDFF() {
+        return isDFF;
+    }
+
     private static final class AsIterable<T> implements Iterable<T> {
         private final T item;
 

diff --git a/src/test/java/de/neemann/digital/analyse/DetermineJKStateMachineTest.java b/src/test/java/de/neemann/digital/analyse/DetermineJKStateMachineTest.java
@@ -40,7 +40,7 @@ public void testSimple() throws Exception {
         DetermineJKStateMachine jk = new DetermineJKStateMachine("a", e);
         assertEquals(toStr(notb), toStr(jk.getJ()));
         assertEquals(toStr(notc), toStr(jk.getK()));
-
+        assertFalse(jk.isDFF());
     }
 
     private String toStr(Expression expression) throws FormatterException {
@@ -54,7 +54,7 @@ public void testSimple2() throws Exception {
         DetermineJKStateMachine jk = new DetermineJKStateMachine("a", e);
         assertEquals("(b ∧ c) ∨ ¬b", toStr(jk.getJ()));
         assertEquals("¬((b ∧ c) ∨ c)", toStr(jk.getK()));
-
+        assertFalse(jk.isDFF());
     }
 
     public void testSimple3() throws Exception {
@@ -63,6 +63,7 @@ public void testSimple3() throws Exception {
         DetermineJKStateMachine jk = new DetermineJKStateMachine("a", e);
         assertEquals("1", toStr(jk.getJ()));
         assertEquals("1", toStr(jk.getK()));
+        assertFalse(jk.isDFF());
     }
 
     public void testSimple4() throws Exception {
@@ -71,6 +72,16 @@ public void testSimple4() throws Exception {
         DetermineJKStateMachine jk = new DetermineJKStateMachine("a", e);
         assertEquals("0", toStr(jk.getJ()));
         assertEquals("0", toStr(jk.getK()));
+        assertFalse(jk.isDFF());
+    }
+
+    public void testSimpleD() throws Exception {
+        Expression e = or(and(a, b), and(nota, notb));
+
+        DetermineJKStateMachine jk = new DetermineJKStateMachine("c", e);
+        assertEquals("(¬a ∧ ¬b) ∨ (a ∧ b)", toStr(jk.getJ()));
+        assertEquals("(¬a ∧ ¬b) ∨ (a ∧ b)", toStr(jk.getNK()));
+        assertTrue(jk.isDFF());
     }
 
 }