1. CPU now correctly sets Zero and Negative flags for LDA, LDX, and LDY

immediate mode instructions.

2. Added unit tests for LDA, LDX, LDY immediate mode instructions.

src/test/java/com/loomcom/lm6502/CpuTest.java

@@ -2,11 +2,18 @@ package com.loomcom.lm6502;
 
 import junit.framework.*;
 
+import com.loomcom.lm6502.devices.*;
+import com.loomcom.lm6502.exceptions.*;
+
 /**
  *
  */
 public class CpuTest extends TestCase {
 
+	private Cpu cpu;
+	private Bus bus;
+	private Memory mem;
+	
 	public CpuTest(String testName) {
 		super(testName);
 	}
@@ -14,10 +21,143 @@ public class CpuTest extends TestCase {
 	public static Test suite() {
 		return new TestSuite(CpuTest.class);
 	}
+	
+	public void setUp() throws MemoryRangeException {
+		this.cpu = new Cpu();
+		this.bus = new Bus(0x0000, 0xffff);
+		this.mem = new Memory(0x0000, 0x10000);
+		bus.addCpu(cpu);
+		bus.addDevice(new Memory(0x0000, 0x10000));
 
-	public void testCpu() {
-		Cpu cpu = new Cpu();
-		assertNotNull(cpu);
+		// All test programs start at 0x0200;
+		bus.write(0xfffc, 0x00);
+		bus.write(0xfffd, 0x02);
+
+		cpu.reset();
+	}
+	
+	public void testReset() {
+		assertEquals(0, cpu.getAccumulator());
+		assertEquals(0, cpu.getXRegister());
+		assertEquals(0, cpu.getYRegister());
+		assertEquals(0x0200, cpu.getProgramCounter());
+		assertFalse(cpu.getCarryFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertFalse(cpu.getIrqDisableFlag());
+		assertFalse(cpu.getDecimalModeFlag());
+		assertFalse(cpu.getBreakFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getNegativeFlag());
+	}
+	
+	/* LDA Immediate Mode Tests - 0xa9 */
+
+	public void test_LDA_IMM_SetsAccumulator() {
+		bus.write(0x0200, 0xa9);
+		bus.write(0x0201, 0x12);
+		cpu.step();
+		assertEquals(0x12, cpu.getAccumulator());
+	}
+	
+	public void test_LDA_IMM_SetsZeroFlagIfArgIsZero() {
+		bus.write(0x0200, 0xa9);
+		bus.write(0x0201, 0x00);
+		cpu.step();
+		assertTrue(cpu.getZeroFlag());
 	}
 
+	public void test_LDA_IMM_DoesNotSetZeroFlagIfArgNotZero() {
+		bus.write(0x0200, 0xa9);
+		bus.write(0x0201, 0x12);
+		cpu.step();
+		assertFalse(cpu.getZeroFlag());		
+	}
+	
+	public void test_LDA_IMM_SetsNegativeFlagIfArgIsNegative() {
+		bus.write(0x0200, 0xa9);
+		bus.write(0x0201, 0x80);
+		cpu.step();
+		assertTrue(cpu.getNegativeFlag());
+	}
+	
+	public void test_LDA_IMM_DoesNotSetNegativeFlagIfArgNotNegative() {
+		bus.write(0x0200, 0xa9);
+		bus.write(0x0201, 0x7f);
+		cpu.step();
+		assertFalse(cpu.getNegativeFlag());
+	}
+
+	/* LDX Immediate Mode Tests - 0xa2 */
+	
+	public void test_LDX_IMM_SetsXRegister() {
+		bus.write(0x0200, 0xa2);
+		bus.write(0x0201, 0x12);
+		cpu.step();
+		assertEquals(0x12, cpu.getXRegister());
+	}
+	
+	public void test_LDX_IMM_SetsZeroFlagIfArgIsZero() {
+		bus.write(0x0200, 0xa2);
+		bus.write(0x0201, 0x00);
+		cpu.step();
+		assertTrue(cpu.getZeroFlag());
+	}
+
+	public void test_LDX_IMM_DoesNotSetZeroFlagIfArgNotZero() {
+		bus.write(0x0200, 0xa2);
+		bus.write(0x0201, 0x12);
+		cpu.step();
+		assertFalse(cpu.getZeroFlag());		
+	}
+	
+	public void test_LDX_IMM_SetsNegativeFlagIfArgIsNegative() {
+		bus.write(0x0200, 0xa2);
+		bus.write(0x0201, 0x80);
+		cpu.step();
+		assertTrue(cpu.getNegativeFlag());
+	}
+	
+	public void test_LDX_IMM_DoesNotSetNegativeFlagIfArgNotNegative() {
+		bus.write(0x0200, 0xa2);
+		bus.write(0x0201, 0x7f);
+		cpu.step();
+		assertFalse(cpu.getNegativeFlag());
+	}
+
+	/* LDY Immediate Mode Tests - 0xa0 */
+	
+	public void test_LDY_IMM_SetsYRegister() {
+		bus.write(0x0200, 0xa0);
+		bus.write(0x0201, 0x12);
+		cpu.step();
+		assertEquals(0x12, cpu.getYRegister());
+	}
+	
+	public void test_LDY_IMM_SetsZeroFlagIfArgIsZero() {
+		bus.write(0x0200, 0xa0);
+		bus.write(0x0201, 0x00);
+		cpu.step();
+		assertTrue(cpu.getZeroFlag());
+	}
+
+	public void test_LDY_IMM_DoesNotSetZeroFlagIfArgNotZero() {
+		bus.write(0x0200, 0xa0);
+		bus.write(0x0201, 0x12);
+		cpu.step();
+		assertFalse(cpu.getZeroFlag());		
+	}
+	
+	public void test_LDY_IMM_SetsNegativeFlagIfArgIsNegative() {
+		bus.write(0x0200, 0xa0);
+		bus.write(0x0201, 0x80);
+		cpu.step();
+		assertTrue(cpu.getNegativeFlag());
+	}
+	
+	public void test_LDY_IMM_DoesNotSetNegativeFlagIfArgNotNegative() {
+		bus.write(0x0200, 0xa0);
+		bus.write(0x0201, 0x7f);
+		cpu.step();
+		assertFalse(cpu.getNegativeFlag());
+	}
 }