Version 1.0.9 - changes by Nick

- fixed disk speed-up bug (Sherwood Forest reads with the drive motor off)
- added check for 2IMG header ID
- fixed processor status bugs in BRK, PLP, RTI, NMI, IRQ

Source/AppleDisplay.java

@@ -2,7 +2,7 @@
 /**
  * AppleIIGo
  * Display processing
- * (C) 2006 by Marc S. Ressl ([email protected])
+ * Copyright 2006 by Marc S. Ressl ([email protected])
  * Released under the GPL
  */
 

Source/AppleIIGo.java

@@ -2,13 +2,18 @@
 /**
  * AppleIIGo
  * The Java Apple II Emulator 
- * Copyright 2011 by Nick Westgate ([email protected])
+ * Copyright 2014 by Nick Westgate ([email protected])
  * Copyright 2006 by Marc S. Ressl ([email protected])
  * Released under the GNU General Public License version 2 
  * See http://www.gnu.org/licenses/
  * 
  * Change list:
  * 
+ * Version 1.0.9 - changes by Nick:
+ * - fixed disk speed-up bug (Sherwood Forest reads with the drive motor off)
+ * - added check for 2IMG header ID
+ * - fixed processor status bugs in BRK, PLP, RTI, NMI, IRQ 
+ * 
  * Version 1.0.8 - changes by Nick:
  * - implemented disk writing (only in memory, not persisted)
  * - added support for .2MG (2IMG) disk images, including lock flag and volume number
@@ -80,7 +85,7 @@ public class AppleIIGo extends Applet implements KeyListener, ComponentListener,
 
 	private static final long serialVersionUID = -3302282815441501352L;
 
-	final String version = "1.0.8";
+	final String version = "1.0.9";
 	final String versionString = "AppleIIGo Version " + version;
 	final String metaStart = "_meta_";
 

Source/AppleSpeaker.java

@@ -2,7 +2,7 @@
 /**
  * AppleIIGo
  * Speaker processing
- * (C) 2006 by Marc S. Ressl([email protected])
+ * Copyright 2006 by Marc S. Ressl([email protected])
  * Released under the GPL
  */
 

Source/DiskII.java

@@ -2,8 +2,8 @@
 /**
  * AppleIIGo
  * Disk II Emulator
- * (C) 2006 by Marc S. Ressl(mressl@gmail.com)
- * (C) 2011 by Nick Westgate (Nick.Westgate@gmail.com)
+ * Copyright 2014 by Nick Westgate (Nick.Westgate@gmail.com)
+ * Copyright 2006 by Marc S. Ressl(mressl@gmail.com)
  * Released under the GPL
  * Based on work by Doug Kwan
  */
@@ -38,6 +38,7 @@ public class DiskII extends Peripheral {
 	private static final int DOS_NUM_TRACKS = 35;
 	private static final int DOS_TRACK_BYTES = 256 * DOS_NUM_SECTORS;
 	private static final int RAW_TRACK_BYTES = 0x1A00; // 0x1A00 (6656) for .NIB (was 6250)
+	private static final int STANDARD_2IMG_HEADER_ID = 0x32494D47;
 	private static final int STANDARD_2IMG_HEADER_SIZE = 64;
 	private static final int STANDARD_PRODOS_BLOCKS = 280;
 
@@ -168,20 +169,8 @@ public int ioRead(int address) {
 				break;
 		}
 
-        if ((address & 1) == 0)
-        {
-        	// only even addresses return the latch
-        	if (isMotorOn)
-        	{
-        		return latchData;
-        	}
-
-        	// simple hack to fool DOS SAMESLOT drive spin check (usually at $BD34)
-        	driveSpin = !driveSpin;
-        	return driveSpin ? 0x7E : 0x7F;
-        }
-
-		return rand.nextInt(256); // TODO: floating bus
+		// only even addresses return the latch
+		return ((address & 1) == 0) ? latchData : rand.nextInt(256); // TODO: floating bus
     }
 
 	/**
@@ -247,7 +236,10 @@ public int memoryRead(int address) {
 	 * Reset peripheral
 	 */
 	public void reset() {
-		ioRead(0x8);
+		drive = 0;
+		isMotorOn = false;
+		loadMode = false;
+		writeMode = false;
 	}
 
 	/**
@@ -266,6 +258,10 @@ public boolean readDisk(int drive, DataInputStream is, String name, boolean isWr
 				byte[] header = new byte[STANDARD_2IMG_HEADER_SIZE];
 				is.readFully(header, 0, STANDARD_2IMG_HEADER_SIZE);
 
+				int id = (header[0x00] << 24) | (header[0x01] << 16) | (header[0x02] << 8) | (header[0x03]);
+				if (id != STANDARD_2IMG_HEADER_ID)
+					return false;
+
 				int headerSize = (header[0x09] << 8) | (header[0x08]);
 				if (headerSize != STANDARD_2IMG_HEADER_SIZE)
 					return false;
@@ -352,6 +348,17 @@ private void ioLatchC() {
 		loadMode = false;
 		if (!writeMode)
 		{
+        	if (!isMotorOn)
+        	{
+            	// simple hack to fool DOS SAMESLOT drive spin check (usually at $BD34)
+            	driveSpin = !driveSpin;
+            	if (driveSpin)
+            	{
+            		latchData = 0x7F;
+        			return;
+            	}
+        	}
+
 			// Read data: C0xE, C0xC
 			latchData = (realTrack[currNibble] & 0xff);
 

Source/Em6502.java

@@ -1,12 +1,14 @@
+import java.io.PrintWriter;
+
 
 /**
  * AppleIIGo
  * Apple II Emulator for J2SE
- * (C) 2006 by Marc S. Ressl([email protected])
+ * Copyright 2006 by Marc S. Ressl([email protected])
  * Released under the GPL
  * Adapted from code by Doug Kwan
  * Adapted from code by Randy Frank [email protected]
- * Adapted from code (C) 1989 Ben Koning [556498717 408/738-1763 [email protected]]
+ * Adapted from code Copyright 1989 Ben Koning [556498717 408/738-1763 [email protected]]
  */
 
 public class Em6502 {
@@ -78,6 +80,7 @@ protected void onIRQ() {
 	public static final int FLAG_I = (1 << 2);
 	public static final int FLAG_D = (1 << 3);
 	public static final int FLAG_B = (1 << 4);
+	public static final int FLAG_R = (1 << 6);
 	public static final int FLAG_V = (1 << 6);
 	public static final int FLAG_N = (1 << 7);
 	/*
@@ -120,6 +123,8 @@ protected void onIRQ() {
 	 * Constructor
 	 */
 	public Em6502() {
+//		createRunFile();
+
 		// Init BCD tables
 		BCDTableAdd = new int[512];
 		BCDTableSub = new int[512];
@@ -133,6 +138,10 @@ public Em6502() {
 			BCDTableSub[i] = ((i & 0x0f) <= 0x09) ? i : (i - 0x06);
 			BCDTableSub[i] -= ((BCDTableSub[i] & 0xf0) <= 0x90) ? 0 : 0x60;
 		}
+
+		// Init CPU
+        S = 0xFF;
+		P = FLAG_B | FLAG_R;
 	}
 
 	/*
@@ -294,9 +303,39 @@ private final void branch(int operand) {
 		clock++;
 	}
 
+//	private PrintWriter runFile;
+//	private void createRunFile()
+//	{
+//		try
+//		{
+//			runFile = new PrintWriter("C:\\Users\\Public\\AppleIIGoRun.txt");
+//		}
+//		catch (Exception ex)
+//		{
+//			// swallow
+//		}
+//	}
+//	private final void writeRunFile(int opcode)
+//	{
+//        if (
+//        		(PC > 0x0500)
+//        		&&
+//        		(PC < 0x0600)
+//        	)
+//        {
+//			setN(getFN());
+//			setZ(getFZ());
+//			setC(getFC());
+//
+//			runFile.printf("%04X-%02X P=%02X A=%02X\r\n", PC, opcode, P, A);
+//			runFile.flush();
+//        }
+//	}
+
 	/** This executes a single instruction. */
 	private final void executeInstruction() {
 		opcode = memoryRead(PC);
+//		writeRunFile(opcode);
 		PC++;
 
 		switch(opcode) {
@@ -535,8 +574,7 @@ private final void executeInstruction() {
 			setN(getFN());
 			setZ(getFZ());
 			setC(getFC());
-			setB(true);
-			push(P);
+			push(P); // break flag is always set
 			setI(true);
 			PC = memoryRead(0xfffe);
 			PC |= memoryRead(0xffff) << 8;
@@ -1043,7 +1081,7 @@ private final void executeInstruction() {
 			break;
 
 		case 0x28:	// PLP
-			P = pop() | 0x20; // fix bug in bit5 of P
+			P = pop() | FLAG_B | FLAG_R; // fix bug in bit5 of P
 			setFC(getC());
 			setFNZ(getN(), getZ());
 			clock += 4;
@@ -1144,7 +1182,7 @@ private final void executeInstruction() {
 			break;
 
 		case 0x40:	// RTI
-			P = pop() | 0x20; // bit 5 bug of 6502
+			P = pop() | FLAG_B | FLAG_R; // bit 5 bug of 6502
 			setFC(getC());
 			setFNZ(getN(), getZ());
 			PC = pop();	// splitting is necessary
@@ -1570,13 +1608,13 @@ public final void checkInterrupts() {
 		if ((exceptionRegister & SIG_6502_RESET) != 0) {
 			onReset();
 
-			PC = memoryRead(0xfffc);
-			PC |= (memoryRead(0xfffd) << 8);
-			S = (S - 3) & 0xff;
-			setI(true);
 			setD(false); // not on NMOS 6502
 			setFC(getC());
 			setFNZ(getN(), getZ());
+			S = (S - 3) & 0xff;
+			setI(true);
+			PC = memoryRead(0xfffc);
+			PC |= (memoryRead(0xfffd) << 8);
 			clock += 7;
 			exceptionRegister &= ~SIG_6502_RESET;
 		}
@@ -1590,7 +1628,8 @@ public final void checkInterrupts() {
 			setN(getFN());
 			setZ(getFZ());
 			setC(getFC());
-			push(P);
+			push(P & ~FLAG_B);
+			setI(true);
 			PC = memoryRead(0xfffa);
 			PC |= memoryRead(0xfffb) << 8;
 			clock += 7;
@@ -1608,8 +1647,7 @@ public final void checkInterrupts() {
 				setN(getFN());
 				setZ(getFZ());
 				setC(getFC());
-				setB(false);
-				push(P);
+				push(P & ~FLAG_B);
 				setI(true);
 				PC = memoryRead(0xfffe);
 				PC |= memoryRead(0xffff) << 8;

Source/EmAppleII.java

@@ -2,7 +2,7 @@
 /**
  * AppleIIGo
  * Apple II Emulator for J2ME
- * (C) 2006 by Marc S. Ressl([email protected])
+ * Copyright 2006 by Marc S. Ressl([email protected])
  * Released under the GPL
  */
 

Source/Paddle.java

@@ -2,7 +2,7 @@
 /**
 * AppleIIGo
  * Apple II Emulator for J2ME
- * (C) 2006 by Marc S. Ressl([email protected])
+ * Copyright 2006 by Marc S. Ressl([email protected])
  * Released under the GPL
  */
 

Source/Peripheral.java

@@ -2,7 +2,7 @@
 /**
  * AppleIIGo
  * Slot interface
- * (C) 2006 by Marc S. Ressl([email protected])
+ * Copyright 2006 by Marc S. Ressl([email protected])
  * Released under the GPL
  * Based on work by Steven E. Hugg
  */