A lot of performance improvements

.classpath

@@ -6,7 +6,7 @@
 			<attribute name="maven.pomderived" value="true"/>
 		</attributes>
 	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8">
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER">
 		<attributes>
 			<attribute name="maven.pomderived" value="true"/>
 		</attributes>

.gitignore

@@ -10,6 +10,7 @@
 
 /target/
 /backups/
+/Resources_and_Videos/
 
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*

.settings/org.eclipse.jdt.core.prefs

@@ -1,6 +1,14 @@
 eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.methodParameters=do not generate
 org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
 org.eclipse.jdt.core.compiler.compliance=1.8
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
 org.eclipse.jdt.core.compiler.problem.forbiddenReference=warning
 org.eclipse.jdt.core.compiler.source=1.8
 org.eclipse.jdt.core.javaFormatter=org.eclipse.jdt.core.defaultJavaFormatter

src/main/java/org/warp/picalculator/gui/DisplayManager.java

@@ -1,6 +1,7 @@
 package org.warp.picalculator.gui;
 
 import java.io.IOException;
+import java.util.concurrent.Semaphore;
 
 import org.warp.picalculator.Main;
 import org.warp.picalculator.Utils;
@@ -234,6 +235,13 @@ public final class DisplayManager implements RenderingLoop {
 	}
 
 	private void draw_init() {
+		if (engine.supportsFontRegistering()) {
+			for (BinaryFont f : engine.getRegisteredFonts()) {
+				if (!f.isInitialized()) {
+					f.initialize(engine);
+				}
+			}
+		}
 		renderer.glClear(engine.getWidth(), engine.getHeight());
 	}
 
@@ -375,11 +383,12 @@ public final class DisplayManager implements RenderingLoop {
 
 	public void loop() {
 		try {
-			load_skin();
-			load_fonts();
 			engine.create();
 			renderer = engine.getRenderer();
 
+			load_skin();
+			load_fonts();
+			
 			try {
 				screen.initialize();
 			} catch (final Exception e) {

src/main/java/org/warp/picalculator/gui/graphicengine/GraphicEngine.java

@@ -1,6 +1,7 @@
 package org.warp.picalculator.gui.graphicengine;
 
 import java.io.IOException;
+import java.util.ArrayList;
 
 public interface GraphicEngine {
 
@@ -15,6 +16,8 @@ public interface GraphicEngine {
 	public void setDisplayMode(final int ww, final int wh);
 
 	public void create();
+	
+	public void create(Runnable object);
 
 	public boolean wasResized();
 
@@ -39,4 +42,8 @@ public interface GraphicEngine {
 	public boolean isSupported();
 
 	public boolean doesRefreshPauses();
+
+	public boolean supportsFontRegistering();
+	
+	public ArrayList<BinaryFont> getRegisteredFonts();
 }

src/main/java/org/warp/picalculator/gui/graphicengine/Skin.java

@@ -7,6 +7,8 @@ public interface Skin {
 	public void load(String file) throws IOException;
 
 	public void initialize(GraphicEngine d);
+	
+	public boolean isInitialized();
 
 	public void use(GraphicEngine d);
 }

src/main/java/org/warp/picalculator/gui/graphicengine/cpu/CPUEngine.java

@@ -4,6 +4,7 @@ import java.awt.FontMetrics;
 import java.awt.GraphicsEnvironment;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
+import java.util.ArrayList;
 
 import javax.swing.UIManager;
 import javax.swing.UnsupportedLookAndFeelException;
@@ -45,14 +46,21 @@ public class CPUEngine implements GraphicEngine {
 		g = new BufferedImage(ww, wh, BufferedImage.TYPE_INT_ARGB);
 		INSTANCE.wasResized = false;
 	}
-
+	
 	@Override
 	public void create() {
+		create(null);
+	}
+	
+	@Override
+	public void create(Runnable onInitialized) {
 		INSTANCE = new SwingWindow(this);
 		setResizable(Utils.debugOn & !Utils.debugThirdScreen);
 		setDisplayMode(Main.screenSize[0], Main.screenSize[1]);
 		INSTANCE.setVisible(true);
 		initialized = true;
+		if (onInitialized != null)
+			onInitialized.run();
 	}
 
 	@Override
@@ -185,4 +193,16 @@ public class CPUEngine implements GraphicEngine {
 	public boolean doesRefreshPauses() {
 		return true;
 	}
+
+	@Override
+	public boolean supportsFontRegistering() {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public ArrayList<BinaryFont> getRegisteredFonts() {
+		// TODO Auto-generated method stub
+		return null;
+	}
 }

src/main/java/org/warp/picalculator/gui/graphicengine/cpu/CPUFont.java

@@ -149,8 +149,6 @@ public class CPUFont implements BinaryFont {
 
 	@Override
 	public void initialize(GraphicEngine d) {
-		// TODO Auto-generated method stub
-
 	}
 
 	@Override
@@ -178,4 +176,9 @@ public class CPUFont implements BinaryFont {
 		return charH;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 }

src/main/java/org/warp/picalculator/gui/graphicengine/cpu/CPUSkin.java

@@ -48,4 +48,9 @@ public class CPUSkin implements Skin {
 		((CPURenderer) d.getRenderer()).currentSkin = this;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 }

src/main/java/org/warp/picalculator/gui/graphicengine/gpu/GPUEngine.java

@@ -1,10 +1,12 @@
 package org.warp.picalculator.gui.graphicengine.gpu;
 
 import java.io.IOException;
+import java.util.ArrayList;
 
 import org.warp.picalculator.Main;
 import org.warp.picalculator.Utils;
 import org.warp.picalculator.gui.graphicengine.BinaryFont;
+import org.warp.picalculator.gui.graphicengine.GraphicEngine;
 import org.warp.picalculator.gui.graphicengine.RenderingLoop;
 import org.warp.picalculator.gui.graphicengine.Skin;
 
@@ -18,6 +20,7 @@ public class GPUEngine implements org.warp.picalculator.gui.graphicengine.Graphi
 	private RenderingLoop d;
 	private GPURenderer r;
 	int[] size = new int[] { Main.screenSize[0], Main.screenSize[1] };
+	private final ArrayList<BinaryFont> registeredFonts = new ArrayList<BinaryFont>();
 
 	@Override
 	public int[] getSize() {
@@ -53,6 +56,11 @@ public class GPUEngine implements org.warp.picalculator.gui.graphicengine.Graphi
 
 	@Override
 	public void create() {
+		create(null);
+	}
+	
+	@Override
+	public void create(Runnable onInitialized) {
 		created = true;
 		r = new GPURenderer();
 		wnd = new NEWTWindow(this);
@@ -60,6 +68,7 @@ public class GPUEngine implements org.warp.picalculator.gui.graphicengine.Graphi
 		setDisplayMode(Main.screenSize[0], Main.screenSize[1]);
 		setResizable(Utils.debugOn & !Utils.debugThirdScreen);
 		initialized = true;
+		wnd.onInitialized = onInitialized;
 	}
 
 	@Override
@@ -104,12 +113,12 @@ public class GPUEngine implements org.warp.picalculator.gui.graphicengine.Graphi
 
 	@Override
 	public BinaryFont loadFont(String file) throws IOException {
-		return new GPUFont(file);
+		return new GPUFont(this, file);
 	}
 
 	@Override
 	public Skin loadSkin(String file) throws IOException {
-		return new GPUSkin(file);
+		return new GPUSkin(this, file);
 	}
 
 	@Override
@@ -145,5 +154,19 @@ public class GPUEngine implements org.warp.picalculator.gui.graphicengine.Graphi
 	public boolean doesRefreshPauses() {
 		return false;
 	}
+	
+	public void registerFont(GPUFont gpuFont) {
+		registeredFonts.add(gpuFont);
+	}
+
+	@Override
+	public boolean supportsFontRegistering() {
+		return true;
+	}
+
+	@Override
+	public ArrayList<BinaryFont> getRegisteredFonts() {
+		return registeredFonts;
+	}
 
 }

src/main/java/org/warp/picalculator/gui/graphicengine/gpu/GPUFont.java

@@ -25,10 +25,11 @@ public class GPUFont implements BinaryFont {
 	public int memoryWidthOfEachColumn;
 
 	private boolean initialized = false;
-	private CPUFont tmpFont;
+	private BufferedImage tmpFont;
 
-	GPUFont(String file) throws IOException {
+	GPUFont(GraphicEngine g, String file) throws IOException {
 		load(file);
+		((GPUEngine) g).registerFont(this);
 	}
 
 	@Override
@@ -38,7 +39,7 @@ public class GPUFont implements BinaryFont {
 		charH = font.charH;
 		minCharIndex = font.minBound;
 		maxCharIndex = font.maxBound;
-		tmpFont = font;
+		pregenTexture(font.rawchars);
 		font = null;
 	}
 
@@ -56,7 +57,7 @@ public class GPUFont implements BinaryFont {
 		return (ch & 0xFFFF) - minCharIndex;
 	}
 
-	private void genTexture(boolean[][] chars) {
+	private void pregenTexture(boolean[][] chars) {
 		final double totalChars = maxCharIndex - minCharIndex;
 		final int w = powerOf2((int) (Math.ceil(Math.sqrt(totalChars) * charW)));
 		final int h = powerOf2((int) (Math.ceil(Math.sqrt(totalChars) * charH)));
@@ -86,11 +87,17 @@ public class GPUFont implements BinaryFont {
 			memoryWidth = w;
 			memoryHeight = h;
 			memoryWidthOfEachColumn = maxIndexW;
-			texture = GPURenderer.importTexture(bfi);
 			textureW = bfi.getWidth();
 			textureH = bfi.getHeight();
-			bfi.flush();
+			this.tmpFont = bfi;
-			bfi = null;
+		} catch (GLException e) {
+			e.printStackTrace();
+		}
+	}
+	
+	private void genTexture() {
+		try {
+			texture = GPURenderer.importTexture(tmpFont);
 		} catch (GLException | IOException e) {
 			e.printStackTrace();
 		}
@@ -102,9 +109,7 @@ public class GPUFont implements BinaryFont {
 
 	@Override
 	public void initialize(GraphicEngine d) {
-		genTexture(tmpFont.rawchars);
+		genTexture();
-		tmpFont.chars32 = null;
-		tmpFont.rawchars = null;
 		tmpFont = null;
 		initialized = true;
 	}
@@ -138,4 +143,9 @@ public class GPUFont implements BinaryFont {
 	public int getCharacterHeight() {
 		return charH;
 	}
+
+	@Override
+	public boolean isInitialized() {
+		return initialized;
+	}
 }

src/main/java/org/warp/picalculator/gui/graphicengine/gpu/GPURenderer.java

@@ -3,6 +3,7 @@ package org.warp.picalculator.gui.graphicengine.gpu;
 import java.awt.image.BufferedImage;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;

src/main/java/org/warp/picalculator/gui/graphicengine/gpu/GPUSkin.java

@@ -20,7 +20,7 @@ public class GPUSkin implements Skin {
 	private String texturePath;
 	private boolean initialized = false;
 
-	GPUSkin(String file) throws IOException {
+	GPUSkin(GraphicEngine d, String file) throws IOException {
 		load(file);
 	}
 
@@ -57,4 +57,9 @@ public class GPUSkin implements Skin {
 		r.useTexture(t, w, h);
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return initialized;
+	}
+
 }

src/main/java/org/warp/picalculator/gui/graphicengine/gpu/NEWTWindow.java

@@ -60,6 +60,7 @@ class NEWTWindow implements GLEventListener {
 
 	private final GPUEngine disp;
 	private final GPURenderer renderer;
+	public Runnable onInitialized;
 
 	public NEWTWindow(GPUEngine disp) {
 		this.disp = disp;
@@ -279,7 +280,7 @@ class NEWTWindow implements GLEventListener {
 	@Override
 	public void init(GLAutoDrawable drawable) {
 		final GL2ES1 gl = drawable.getGL().getGL2ES1();
-
+		
 		//Vsync
 		gl.setSwapInterval(2);
 
@@ -291,6 +292,10 @@ class NEWTWindow implements GLEventListener {
 		gl.glBlendFunc(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA);
 		gl.glShadeModel(GLLightingFunc.GL_FLAT);
 
+		if (onInitialized != null) {
+			onInitialized.run();
+			onInitialized = null;
+		}
 		try {
 			renderer.currentTex = ((GPUSkin) disp.loadSkin("test.png")).t;
 		} catch (final Exception e) {
@@ -330,7 +335,7 @@ class NEWTWindow implements GLEventListener {
 	@Override
 	public void display(GLAutoDrawable glad) {
 		final GL2ES1 gl = glad.getGL().getGL2ES1();
-
+		
 		GPURenderer.gl = gl;
 
 		gl.glEnableClientState(GLPointerFunc.GL_COLOR_ARRAY);

src/main/java/org/warp/picalculator/gui/graphicengine/headless24bit/Headless24bitEngine.java

@@ -6,6 +6,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
+import java.util.ArrayList;
 import java.util.logging.ConsoleHandler;
 
 import org.fusesource.jansi.AnsiConsole;
@@ -16,6 +17,7 @@ import org.warp.picalculator.Main;
 import org.warp.picalculator.Utils;
 import org.warp.picalculator.device.Keyboard;
 import org.warp.picalculator.device.Keyboard.Key;
+import org.warp.picalculator.gui.graphicengine.BinaryFont;
 import org.warp.picalculator.gui.graphicengine.Renderer;
 import org.warp.picalculator.gui.graphicengine.RenderingLoop;
 
@@ -64,6 +66,11 @@ public class Headless24bitEngine implements org.warp.picalculator.gui.graphiceng
 	
 	@Override
 	public void create() {
+		this.create(null);
+	}
+	
+	@Override
+	public void create(Runnable onInitialized) {
 		Utils.outputLevel = -1;
 		AnsiConsole.systemInstall();
 		if(Utils.isWindows() && !Utils.msDosMode){
@@ -134,6 +141,8 @@ public class Headless24bitEngine implements org.warp.picalculator.gui.graphiceng
 			t.start();
 		}
 		stopped = false;
+		if (onInitialized != null)
+			onInitialized.run();
 	}
 
 	@Override
@@ -321,4 +330,14 @@ public class Headless24bitEngine implements org.warp.picalculator.gui.graphiceng
 	public boolean doesRefreshPauses() {
 		return true;
 	}
+
+	@Override
+	public boolean supportsFontRegistering() {
+		return false;
+	}
+
+	@Override
+	public ArrayList<BinaryFont> getRegisteredFonts() {
+		return null;
+	}
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless24bit/Headless24bitFont.java

@@ -39,4 +39,9 @@ public class Headless24bitFont implements BinaryFont {
 		return 5;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless24bit/Headless24bitSkin.java

@@ -57,5 +57,10 @@ public class Headless24bitSkin implements Skin {
 		((Headless24bitRenderer) d.getRenderer()).currentSkin = this;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless256/Headless256Engine.java

@@ -1,6 +1,7 @@
 package org.warp.picalculator.gui.graphicengine.headless256;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.logging.ConsoleHandler;
 
 import org.fusesource.jansi.AnsiConsole;
@@ -9,6 +10,7 @@ import org.warp.picalculator.Main;
 import org.warp.picalculator.Utils;
 import org.warp.picalculator.device.Keyboard;
 import org.warp.picalculator.device.Keyboard.Key;
+import org.warp.picalculator.gui.graphicengine.BinaryFont;
 import org.warp.picalculator.gui.graphicengine.Renderer;
 import org.warp.picalculator.gui.graphicengine.RenderingLoop;
 import org.warp.picalculator.gui.graphicengine.headless24bit.Headless24bitRenderer;
@@ -56,6 +58,11 @@ public class Headless256Engine implements org.warp.picalculator.gui.graphicengin
 
 	@Override
 	public void create() {
+		this.create(null);
+	}
+	
+	@Override
+	public void create(Runnable onInitialized) {
 		Utils.outputLevel = -1;
 		AnsiConsole.systemInstall();
 		if(Utils.isWindows() && !Utils.msDosMode){
@@ -126,6 +133,8 @@ public class Headless256Engine implements org.warp.picalculator.gui.graphicengin
 			t.start();
 		}
 		stopped = false;
+		if (onInitialized != null)
+			onInitialized.run();
 	}
 
 	@Override
@@ -271,4 +280,16 @@ public class Headless256Engine implements org.warp.picalculator.gui.graphicengin
 	public boolean doesRefreshPauses() {
 		return true;
 	}
+
+	@Override
+	public boolean supportsFontRegistering() {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public ArrayList<BinaryFont> getRegisteredFonts() {
+		// TODO Auto-generated method stub
+		return null;
+	}
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless256/Headless256Font.java

@@ -39,4 +39,9 @@ public class Headless256Font implements BinaryFont {
 		return 5;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless256/Headless256Skin.java

@@ -61,5 +61,10 @@ public class Headless256Skin implements Skin {
 		((Headless256Renderer) d.getRenderer()).currentSkin = this;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless8/Headless8Engine.java

@@ -1,6 +1,7 @@
 package org.warp.picalculator.gui.graphicengine.headless8;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.logging.ConsoleHandler;
 
 import org.fusesource.jansi.AnsiConsole;
@@ -9,6 +10,8 @@ import org.warp.picalculator.Main;
 import org.warp.picalculator.Utils;
 import org.warp.picalculator.device.Keyboard;
 import org.warp.picalculator.device.Keyboard.Key;
+import org.warp.picalculator.gui.graphicengine.BinaryFont;
+import org.warp.picalculator.gui.graphicengine.GraphicEngine;
 import org.warp.picalculator.gui.graphicengine.Renderer;
 import org.warp.picalculator.gui.graphicengine.RenderingLoop;
 import org.warp.picalculator.gui.graphicengine.headless24bit.Headless24bitRenderer;
@@ -56,6 +59,11 @@ public class Headless8Engine implements org.warp.picalculator.gui.graphicengine.
 
 	@Override
 	public void create() {
+		this.create(null);
+	}
+	
+	@Override
+	public void create(Runnable onInitialized) {
 		Utils.outputLevel = -1;
 		AnsiConsole.systemInstall();
 		if(Utils.isWindows() && !Utils.msDosMode){
@@ -126,6 +134,8 @@ public class Headless8Engine implements org.warp.picalculator.gui.graphicengine.
 			t.start();
 		}
 		stopped = false;
+		if (onInitialized != null)
+			onInitialized.run();
 	}
 
 	@Override
@@ -271,4 +281,16 @@ public class Headless8Engine implements org.warp.picalculator.gui.graphicengine.
 	public boolean doesRefreshPauses() {
 		return true;
 	}
+
+	@Override
+	public boolean supportsFontRegistering() {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public ArrayList<BinaryFont> getRegisteredFonts() {
+		// TODO Auto-generated method stub
+		return null;
+	}
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless8/Headless8Font.java

@@ -39,4 +39,9 @@ public class Headless8Font implements BinaryFont {
 		return 5;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 }

src/main/java/org/warp/picalculator/gui/graphicengine/headless8/Headless8Skin.java

@@ -56,5 +56,10 @@ public class Headless8Skin implements Skin {
 		((Headless8Renderer) d.getRenderer()).currentSkin = this;
 	}
 
+	@Override
+	public boolean isInitialized() {
+		return true;
+	}
+
 
 }

src/main/java/org/warp/picalculator/math/functions/Division.java

@@ -60,7 +60,8 @@ public class Division extends FunctionOperator {
 					if (((Number) variable1).isInteger() && ((Number) variable2).isInteger()) {
 						LinkedList<BigInteger> factors1 = ((Number) variable1).getFactors();
 						LinkedList<BigInteger> factors2 = ((Number) variable2).getFactors();
-						return factors1.retainAll(factors2) /* True If something changed in the factors list by keeping only the intersection of the two factor lists */ && factors1.size() > 0 /* true if there is at least one common factor */;
+						factors1.retainAll(factors2);
+						return factors1.size() > 0 /* true if there is at least one common factor */;
 					} else if (((Number) variable1).divide((Number) variable2).isInteger()) {
 						return true;
 					} else {
@@ -99,15 +100,14 @@ public class Division extends FunctionOperator {
 			if (getMathContext().exactMode && (((Number) variable1).isInteger() && ((Number) variable2).isInteger())) {
 				LinkedList<BigInteger> factors1 = ((Number) variable1).getFactors();
 				LinkedList<BigInteger> factors2 = ((Number) variable2).getFactors();
-				if(factors1.retainAll(factors2)) { //True If something changed in the factors list by keeping only the intersection of the two factor lists.
+				factors1.retainAll(factors2);
-					BigInteger nmb1 = ((Number) this.getParameter1()).term.toBigIntegerExact();
+				BigInteger nmb1 = ((Number) this.getParameter1()).term.toBigIntegerExact();
-					BigInteger nmb2 = ((Number) this.getParameter2()).term.toBigIntegerExact();
+				BigInteger nmb2 = ((Number) this.getParameter2()).term.toBigIntegerExact();
-					for (BigInteger i : factors1) {
+				for (BigInteger i : factors1) {
-						nmb1 = nmb1.divide(i);
+					nmb1 = nmb1.divide(i);
-						nmb2 = nmb2.divide(i);
+					nmb2 = nmb2.divide(i);
-					}
-					result.add(new Division(mathContext, new Number(mathContext, nmb1), new Number(mathContext, nmb2)));
 				}
+				result.add(new Division(mathContext, new Number(mathContext, nmb1), new Number(mathContext, nmb2)));
 			} else {
 				result.add(((Number) variable1).divide((Number) variable2));
 			}

src/main/java/org/warp/picalculator/math/functions/Number.java

@@ -75,10 +75,13 @@ public class Number implements Function {
 	public Number pow(Number f) throws Error {
 		Number ret = new Number(root, BigDecimal.ONE);
 		if (Utils.isIntegerValue(f.term)) {
-			final BigInteger bi = f.term.toBigInteger();
+			final BigInteger bi = f.term.toBigInteger().abs();
 			for (BigInteger i = BigInteger.ZERO; i.compareTo(bi) < 0; i = i.add(BigInteger.ONE)) {
 				ret = ret.multiply(new Number(root, getTerm()));
 			}
+			if (f.term.signum() == -1) {
+				ret = new Number(root, 1).divide(ret);
+			}
 		} else {
 			ret.term = BigDecimalMath.pow(term, f.term);
 		}

src/main/resources/.gitignore

@@ -0,0 +1 @@
+/Thumbs.db