adds a pseudo random number generator, see #598

src/main/java/de/neemann/digital/analyse/SubstituteLibrary.java

@@ -144,7 +144,7 @@ public class SubstituteLibrary implements LibraryInterface {
             c.getAttributes().set(Keys.IS_GENERIC, false);
             generify(attr, c);
 
-            return ElementLibrary.createCustomDescription(new File(filename), c, library).isSubstitutedBuiltIn();
+            return ElementLibrary.createCustomDescription(new File(filename), c).isSubstitutedBuiltIn();
         }
 
         private void generify(ElementAttributes attr, Circuit circuit) throws IOException {

src/main/java/de/neemann/digital/core/arithmetic/PRNG.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2021 Helmut Neemann.
+ * Use of this source code is governed by the GPL v3 license
+ * that can be found in the LICENSE file.
+ */
+package de.neemann.digital.core.arithmetic;
+
+import de.neemann.digital.core.*;
+import de.neemann.digital.core.element.Element;
+import de.neemann.digital.core.element.ElementAttributes;
+import de.neemann.digital.core.element.ElementTypeDescription;
+import de.neemann.digital.core.element.Keys;
+
+import java.util.Random;
+
+import static de.neemann.digital.core.element.PinInfo.input;
+
+/**
+ * Creates a random number using the Java Random class.
+ */
+public class PRNG extends Node implements Element {
+
+    /**
+     * The element type description
+     */
+    public static final ElementTypeDescription DESCRIPTION = new ElementTypeDescription(PRNG.class,
+            input("S"),
+            input("se"),
+            input("ne"),
+            input("C").setClock())
+            .addAttribute(Keys.ROTATE)
+            .addAttribute(Keys.BITS)
+            .addAttribute(Keys.LABEL);
+
+    private final ObservableValue output;
+    private final int bits;
+    private final long mask;
+    private final Random random;
+    private ObservableValue seedVal;
+    private ObservableValue setVal;
+    private ObservableValue nextVal;
+    private ObservableValue clockVal;
+    private boolean lastClock;
+    private long value;
+
+    /**
+     * Creates a new instance
+     *
+     * @param attributes the elements attributes
+     */
+    public PRNG(ElementAttributes attributes) {
+        bits = attributes.get(Keys.BITS);
+        output = new ObservableValue("R", bits).setPinDescription(DESCRIPTION);
+        // Let Java set the initial seed so that different values are generated each simulation,
+        // unless a specific seed is set by the user later on.
+        random = new Random();
+        mask = Bits.mask(bits);
+        value = random.nextLong() & mask;
+    }
+
+    @Override
+    public void readInputs() throws NodeException {
+        boolean clock = clockVal.getBool();
+
+        if (clock && !lastClock) {
+            // First update seed
+            if (setVal.getBool())
+                random.setSeed(seedVal.getValue());
+
+            // Then value. This keeps the component well defined in case both 'set' and 'next' inputs are set.
+            if (nextVal.getBool())
+                value = random.nextLong() & mask;
+        }
+
+        lastClock = clock;
+    }
+
+    @Override
+    public void writeOutputs() throws NodeException {
+        output.setValue(value);
+    }
+
+    @Override
+    public void setInputs(ObservableValues inputs) throws NodeException {
+        // Note: could separate bit count for seed input & value output
+        seedVal = inputs.get(0).checkBits(bits, this);
+        setVal = inputs.get(1).checkBits(1, this);
+        nextVal = inputs.get(2).checkBits(1, this);
+        clockVal = inputs.get(3).addObserverToValue(this).checkBits(1, this);
+    }
+
+    @Override
+    public ObservableValues getOutputs() {
+        return output.asList();
+    }
+
+}

src/main/java/de/neemann/digital/draw/library/ElementLibrary.java

@@ -89,9 +89,9 @@ public class ElementLibrary implements Iterable<ElementLibrary.ElementContainer>
     private final HashSet<String> isProgrammable = new HashSet<>();
     private final ArrayList<LibraryListener> listeners = new ArrayList<>();
     private final LibraryNode root;
+    private final ElementLibraryFolder custom;
     private JarComponentManager jarComponentManager;
     private ShapeFactory shapeFactory;
-    private ElementLibraryFolder custom;
     private File rootLibraryPath;
     private Exception exception;
     private long lastRescanTime;
@@ -197,7 +197,8 @@ public class ElementLibrary implements Iterable<ElementLibrary.ElementContainer>
                         .add(ROM.DESCRIPTION)
                         .add(ROMDualPort.DESCRIPTION)
                         .add(Counter.DESCRIPTION)
-                        .add(CounterPreset.DESCRIPTION))
+                        .add(CounterPreset.DESCRIPTION)
+                        .add(PRNG.DESCRIPTION))
                 .add(new LibraryNode(Lang.get("lib_arithmetic"))
                         .add(Add.DESCRIPTION)
                         .add(Sub.DESCRIPTION)
@@ -588,7 +589,7 @@ public class ElementLibrary implements Iterable<ElementLibrary.ElementContainer>
                 throw new IOException(Lang.get("err_couldNotFindIncludedFile_N0", file));
             }
 
-            ElementTypeDescriptionCustom description = createCustomDescription(file, circuit, this);
+            ElementTypeDescriptionCustom description = createCustomDescription(file, circuit);
             description.setShortName(createShortName(file.getName(), circuit.getAttributes().getLabel()));
 
             String descriptionText = Lang.evalMultilingualContent(circuit.getAttributes().get(Keys.DESCRIPTION));
@@ -620,11 +621,10 @@ public class ElementLibrary implements Iterable<ElementLibrary.ElementContainer>
      *
      * @param file    the file
      * @param circuit the circuit
-     * @param library the used library
      * @return the type description
      * @throws PinException PinException
      */
-    public static ElementTypeDescriptionCustom createCustomDescription(File file, Circuit circuit, ElementLibrary library) throws PinException {
+    public static ElementTypeDescriptionCustom createCustomDescription(File file, Circuit circuit) throws PinException {
         ElementTypeDescriptionCustom d = new ElementTypeDescriptionCustom(file, circuit);
         d.setElementFactory(attributes -> new CustomElement(d));
         return d;

src/main/java/de/neemann/digital/gui/Main.java

@@ -375,7 +375,7 @@ public final class Main extends JFrame implements ClosingWindowListener.ConfirmS
                     file = new File(name);
                 try {
                     ElementTypeDescriptionCustom description =
-                            ElementLibrary.createCustomDescription(file, circuit, library);
+                            ElementLibrary.createCustomDescription(file, circuit);
                     description.setShortName(name);
                     description.setDescription(Lang.evalMultilingualContent(circuit.getAttributes().get(Keys.DESCRIPTION)));
                     new ElementHelpDialog(Main.this, description, circuit.getAttributes()).setVisible(true);

src/main/resources/lang/lang_de.xml

@@ -844,6 +844,19 @@
     <string name="elem_BitCount_pin_in">Die 1-Bits in diesem Datenwort werden gezählt.</string>
     <string name="elem_BitCount_pin_out">Ausgang mit der Anzahl der gezählten 1-Bits.</string>
 
+    <string name="elem_PRNG">Zufallszahlengenerator</string>
+    <string name="elem_PRNG_tt">Kann verwendet werden um Zufallszahlen zu erzeugen.
+        Beim Starten der Simulation wird der Generator neu initialisiert, so dass bei jedem Start eine neue
+        Pseudozufallszahlenfolge erzeugt wird.
+        Der Generator kann in der laufenden Simulation mit einem definierten SEED-Wert initialisiert werden,
+        um eine definierte Pseudozufallszahlenfolge erzeugen zu lassen.
+    </string>
+    <string name="elem_PRNG_short">PRNG</string>
+    <string name="elem_PRNG_pin_S">Startwert des Generators</string>
+    <string name="elem_PRNG_pin_se">Wenn gesetzt wird der Zufallsszahlengenerator bei der nächsten steigenden Taktflanke mit dem neuen Startwert reinitialisiert.</string>
+    <string name="elem_PRNG_pin_ne">Wenn gesetzt wird bei der nächsten steigenden Taktflanke eine neue Zufallsszahl ausgegeben.</string>
+    <string name="elem_PRNG_pin_C">Der Takteingang.</string>
+    <string name="elem_PRNG_pin_R">Ausgabe der Pseudozufallszahl.</string>
 
     <!-- Schalter -->
 

src/main/resources/lang/lang_en.xml

@@ -819,6 +819,19 @@
     <string name="elem_BitCount_pin_in">The input which 1-bits are counted.</string>
     <string name="elem_BitCount_pin_out">Outputs the number of 1-bits.</string>
 
+    <string name="elem_PRNG">Random Nnumber Generator</string>
+    <string name="elem_PRNG_tt">Can be used to generate random numbers.
+        When the simulation is started, the generator is reinitialized so that a new pseudo-random number
+        sequence is generated at each start.
+        The generator can be initialized in the running simulation with a defined seed value to generate
+        a defined pseudo-random number sequence.
+    </string>
+    <string name="elem_PRNG_short">PRNG</string>
+    <string name="elem_PRNG_pin_S">New seed value of the generator.</string>
+    <string name="elem_PRNG_pin_se">If set, the random number generator is reinitialized with the new seed value at the next rising clock edge.</string>
+    <string name="elem_PRNG_pin_ne">If set, a new random number is output at the next rising clock edge.</string>
+    <string name="elem_PRNG_pin_C">The clock input.</string>
+    <string name="elem_PRNG_pin_R">Output of the pseudorandom number.</string>
 
     <!-- Switches -->
 

src/test/java/de/neemann/digital/integration/TestExamples.java

@@ -50,8 +50,8 @@ public class TestExamples extends TestCase {
      */
     public void testTestExamples() throws Exception {
         File examples = new File(Resources.getRoot(), "/dig/test");
-        assertEquals(198, new FileScanner(this::check).scan(examples));
+        assertEquals(199, new FileScanner(this::check).scan(examples));
-        assertEquals(187, testCasesInFiles);
+        assertEquals(188, testCasesInFiles);
     }
 
     /**

src/test/resources/dig/backtrack/AllComponents.dig

@@ -687,6 +687,16 @@
       <elementAttributes/>
       <pos x="820" y="940"/>
     </visualElement>
+    <visualElement>
+      <elementName>PRNG</elementName>
+      <elementAttributes>
+        <entry>
+          <string>Bits</string>
+          <int>8</int>
+        </entry>
+      </elementAttributes>
+      <pos x="420" y="1080"/>
+    </visualElement>
   </visualElements>
   <wires>
     <wire>
@@ -737,6 +747,10 @@
       <p1 x="700" y="520"/>
       <p2 x="800" y="520"/>
     </wire>
+    <wire>
+      <p1 x="400" y="1160"/>
+      <p2 x="420" y="1160"/>
+    </wire>
     <wire>
       <p1 x="240" y="780"/>
       <p2 x="260" y="780"/>
@@ -1053,6 +1067,10 @@
       <p1 x="220" y="1080"/>
       <p2 x="240" y="1080"/>
     </wire>
+    <wire>
+      <p1 x="380" y="1080"/>
+      <p2 x="420" y="1080"/>
+    </wire>
     <wire>
       <p1 x="240" y="1080"/>
       <p2 x="260" y="1080"/>
@@ -1169,6 +1187,10 @@
       <p1 x="240" y="1100"/>
       <p2 x="260" y="1100"/>
     </wire>
+    <wire>
+      <p1 x="400" y="1100"/>
+      <p2 x="420" y="1100"/>
+    </wire>
     <wire>
       <p1 x="600" y="720"/>
       <p2 x="680" y="720"/>
@@ -1385,6 +1407,10 @@
       <p1 x="1160" y="500"/>
       <p2 x="1200" y="500"/>
     </wire>
+    <wire>
+      <p1 x="400" y="1140"/>
+      <p2 x="420" y="1140"/>
+    </wire>
     <wire>
       <p1 x="1080" y="760"/>
       <p2 x="1100" y="760"/>
@@ -1681,10 +1707,22 @@
       <p1 x="400" y="960"/>
       <p2 x="400" y="1020"/>
     </wire>
+    <wire>
+      <p1 x="400" y="1020"/>
+      <p2 x="400" y="1100"/>
+    </wire>
     <wire>
       <p1 x="400" y="580"/>
       <p2 x="400" y="780"/>
     </wire>
+    <wire>
+      <p1 x="400" y="1100"/>
+      <p2 x="400" y="1140"/>
+    </wire>
+    <wire>
+      <p1 x="400" y="1140"/>
+      <p2 x="400" y="1160"/>
+    </wire>
     <wire>
       <p1 x="400" y="220"/>
       <p2 x="400" y="260"/>
@@ -2125,6 +2163,10 @@
       <p1 x="380" y="820"/>
       <p2 x="380" y="920"/>
     </wire>
+    <wire>
+      <p1 x="380" y="920"/>
+      <p2 x="380" y="1080"/>
+    </wire>
   </wires>
   <measurementOrdering/>
 </circuit>

src/test/resources/dig/test/prng.dig

@@ -0,0 +1,144 @@
+<?xml version="1.0" encoding="utf-8"?>
+<circuit>
+  <version>1</version>
+  <attributes/>
+  <visualElements>
+    <visualElement>
+      <elementName>PRNG</elementName>
+      <elementAttributes>
+        <entry>
+          <string>Bits</string>
+          <int>8</int>
+        </entry>
+      </elementAttributes>
+      <pos x="460" y="180"/>
+    </visualElement>
+    <visualElement>
+      <elementName>Clock</elementName>
+      <elementAttributes>
+        <entry>
+          <string>Label</string>
+          <string>C</string>
+        </entry>
+      </elementAttributes>
+      <pos x="280" y="260"/>
+    </visualElement>
+    <visualElement>
+      <elementName>Const</elementName>
+      <elementAttributes/>
+      <pos x="440" y="240"/>
+    </visualElement>
+    <visualElement>
+      <elementName>JK_FF</elementName>
+      <elementAttributes/>
+      <pos x="340" y="180"/>
+    </visualElement>
+    <visualElement>
+      <elementName>Ground</elementName>
+      <elementAttributes/>
+      <pos x="320" y="240"/>
+    </visualElement>
+    <visualElement>
+      <elementName>VDD</elementName>
+      <elementAttributes/>
+      <pos x="320" y="160"/>
+    </visualElement>
+    <visualElement>
+      <elementName>Const</elementName>
+      <elementAttributes>
+        <entry>
+          <string>Bits</string>
+          <int>8</int>
+        </entry>
+      </elementAttributes>
+      <pos x="440" y="180"/>
+    </visualElement>
+    <visualElement>
+      <elementName>Out</elementName>
+      <elementAttributes>
+        <entry>
+          <string>Label</string>
+          <string>Y</string>
+        </entry>
+        <entry>
+          <string>Bits</string>
+          <int>8</int>
+        </entry>
+      </elementAttributes>
+      <pos x="560" y="220"/>
+    </visualElement>
+    <visualElement>
+      <elementName>Testcase</elementName>
+      <elementAttributes>
+        <entry>
+          <string>Testdata</string>
+          <testData>
+            <dataString>C Y
+c 0xd8
+c 0x92
+c 0xf0
+c 0xdd
+c 0x68
+c 0x12
+c 0x7e
+c 0xe4
+c 0xfc
+</dataString>
+          </testData>
+        </entry>
+      </elementAttributes>
+      <pos x="360" y="320"/>
+    </visualElement>
+  </visualElements>
+  <wires>
+    <wire>
+      <p1 x="440" y="240"/>
+      <p2 x="460" y="240"/>
+    </wire>
+    <wire>
+      <p1 x="280" y="260"/>
+      <p2 x="300" y="260"/>
+    </wire>
+    <wire>
+      <p1 x="300" y="260"/>
+      <p2 x="460" y="260"/>
+    </wire>
+    <wire>
+      <p1 x="320" y="180"/>
+      <p2 x="340" y="180"/>
+    </wire>
+    <wire>
+      <p1 x="440" y="180"/>
+      <p2 x="460" y="180"/>
+    </wire>
+    <wire>
+      <p1 x="300" y="200"/>
+      <p2 x="340" y="200"/>
+    </wire>
+    <wire>
+      <p1 x="400" y="200"/>
+      <p2 x="460" y="200"/>
+    </wire>
+    <wire>
+      <p1 x="320" y="220"/>
+      <p2 x="340" y="220"/>
+    </wire>
+    <wire>
+      <p1 x="520" y="220"/>
+      <p2 x="560" y="220"/>
+    </wire>
+    <wire>
+      <p1 x="320" y="220"/>
+      <p2 x="320" y="240"/>
+    </wire>
+    <wire>
+      <p1 x="320" y="160"/>
+      <p2 x="320" y="180"/>
+    </wire>
+    <wire>
+      <p1 x="300" y="200"/>
+      <p2 x="300" y="260"/>
+    </wire>
+  </wires>
+  <measurementOrdering/>
+</circuit>