Implemented set/clear flag instructions. More tests, but SBC is still BROKEN.

src/main/java/com/loomcom/symon/Cpu.java

@@ -162,7 +162,8 @@ public class Cpu implements InstructionTable {
 			break;
 		case 0x17: // n/a
 			break;
-		case 0x18: // n/a
+		case 0x18: // CLC - Clear Carry Flag, Implied
+			clearCarryFlag();
 			break;
 		case 0x19: // n/a
 			break;
@@ -230,7 +231,8 @@ public class Cpu implements InstructionTable {
 			break;
 		case 0x37: // n/a
 			break;
-		case 0x38: // n/a
+		case 0x38: // SEC - Set Carry Flag, Implied
+			setCarryFlag();
 			break;
 		case 0x39: // n/a
 			break;
@@ -299,7 +301,8 @@ public class Cpu implements InstructionTable {
 			break;
 		case 0x57: // n/a
 			break;
-		case 0x58: // n/a
+		case 0x58: // CLI - Clear Interrupt Disable, Implied
+			clearIrqDisableFlag();
 			break;
 		case 0x59: // n/a
 			break;
@@ -367,7 +370,8 @@ public class Cpu implements InstructionTable {
 			break;
 		case 0x77: // n/a
 			break;
-		case 0x78: // n/a
+		case 0x78: // SEI - Set Interrupt Disable, Implied
+			setIrqDisableFlag();
 			break;
 		case 0x79: // n/a
 			break;
@@ -505,7 +509,8 @@ public class Cpu implements InstructionTable {
 			break;
 		case 0xb7: // n/a
 			break;
-		case 0xb8: // n/a
+		case 0xb8: // CLV - Clear Overflow Flag, Implied
+			clearOverflowFlag();
 			break;
 		case 0xb9: // n/a
 			break;
@@ -573,7 +578,8 @@ public class Cpu implements InstructionTable {
 			break;
 		case 0xd7: // n/a
 			break;
-		case 0xd8: // n/a
+		case 0xd8: // CLD - Clear Decimal Mode, Implied
+			clearDecimalModeFlag();
 			break;
 		case 0xd9: // n/a
 			break;
@@ -642,7 +648,8 @@ public class Cpu implements InstructionTable {
 			break;
 		case 0xf7: // n/a
 			break;
-		case 0xf8: // n/a
+		case 0xf8: // SED - Set Decimal Flag, Implied
+			setDecimalModeFlag();
 			break;
 		case 0xf9: // n/a
 			break;
@@ -679,8 +686,8 @@ public class Cpu implements InstructionTable {
 	}
 
 	public int sbc(int acc, int operand) {
-		// Equivalent to ADC of the 2's complement of the operand
+		// Equivalent to ADC of the 2's complement of the operand, minus the /carry
-		return adc(acc, (--operand) ^ 0xff);
+		return adc(acc, (--operand ^ 0xff));
 	}
 
 	public void cmp(int reg, int operand) {
@@ -720,119 +727,214 @@ public class Cpu implements InstructionTable {
 	}
 
 	/**
-     * @return the carry flag
+	 * @return the carry flag
-     */
+	 */
-    public boolean getCarryFlag() {
+	public boolean getCarryFlag() {
-    	return carryFlag;
+		return carryFlag;
-    }
+	}
 
 	/**
-     * @param carryFlag the carry flag to set
+	 * @param carryFlag the carry flag to set
-     */
+	 */
-    public void setCarryFlag(boolean carryFlag) {
+	public void setCarryFlag(boolean carryFlag) {
-    	this.carryFlag = carryFlag;
+		this.carryFlag = carryFlag;
-    }
+	}
-
-    /**
-     * @return the zero flag
-     */
-    public boolean getZeroFlag() {
-    	return zeroFlag;
-    }
-
-    /**
-     * @param zeroFlag the zero flag to set
-     */
-    public void setZeroFlag(boolean zeroFlag) {
-    	this.zeroFlag = zeroFlag;
-    }
 
 	/**
-     * @return the irq disable flag
+	 * Sets the Carry Flag
-     */
+	 */
-    public boolean getIrqDisableFlag() {
+	public void setCarryFlag() {
-    	return irqDisableFlag;
+		this.carryFlag = true;
-    }
+	}
 
 	/**
-     * @param irqDisableFlag the irq disable flag to set
+	 * Clears the Carry Flag
-     */
+	 */
-    public void setIrqDisableFlag(boolean irqDisableFlag) {
+	public void clearCarryFlag() {
-    	this.irqDisableFlag = irqDisableFlag;
+		this.carryFlag = false;
-    }
+	}
 
 	/**
-     * @return the decimal mode flag
+	 * @return the zero flag
-     */
+	 */
-    public boolean getDecimalModeFlag() {
+	public boolean getZeroFlag() {
-    	return decimalModeFlag;
+		return zeroFlag;
-    }
+	}
 
 	/**
-     * @param decimalModeFlag the decimal mde flag to set
+	 * @param zeroFlag the zero flag to set
-     */
+	 */
-    public void setDecimalModeFlag(boolean decimalModeFlag) {
+	public void setZeroFlag(boolean zeroFlag) {
-    	this.decimalModeFlag = decimalModeFlag;
+		this.zeroFlag = zeroFlag;
-    }
+	}
 
 	/**
-     * @return the break flag
+	 * Sets the Zero Flag
-     */
+	 */
-    public boolean getBreakFlag() {
+	public void setZeroFlag() {
-    	return breakFlag;
+		this.zeroFlag = true;
-    }
+	}
 
 	/**
-     * @param breakFlag the break flag to set
+	 * Clears the Zero Flag
-     */
+	 */
-    public void setBreakFlag(boolean breakFlag) {
+	public void clearZeroFlag() {
-    	this.breakFlag = breakFlag;
+		this.zeroFlag = false;
-    }
+	}
 
 	/**
-     * @return the overflow flag
+	 * @return the irq disable flag
-     */
+	 */
-    public boolean getOverflowFlag() {
+	public boolean getIrqDisableFlag() {
-    	return overflowFlag;
+		return irqDisableFlag;
-    }
+	}
 
 	/**
-     * @param overflowFlag the overflow flag to set
+	 * @param irqDisableFlag the irq disable flag to set
-     */
+	 */
-    public void setOverflowFlag(boolean overflowFlag) {
+	public void setIrqDisableFlag(boolean irqDisableFlag) {
-    	this.overflowFlag = overflowFlag;
+		this.irqDisableFlag = irqDisableFlag;
-    }
+	}
 
-    public int getAccumulator() {
+	public void setIrqDisableFlag() {
-    	return a;
+		this.irqDisableFlag = true;
-    }
+	}
 
-    public int getXRegister() {
+	public void clearIrqDisableFlag() {
-    	return x;
+		this.irqDisableFlag = false;
-    }
+	}
 
-    public int getYRegister() {
-    	return y;
-    }
 
-    public int getProgramCounter() {
+	/**
-    	return pc;
+	 * @return the decimal mode flag
-    }
+	 */
+	public boolean getDecimalModeFlag() {
+		return decimalModeFlag;
+	}
 
-    /**
+	/**
-     * @return A string representing the current status register state.
+	 * @param decimalModeFlag the decimal mode flag to set
-     */
+	 */
-    public String statusRegisterString() {
+	public void setDecimalModeFlag(boolean decimalModeFlag) {
-    	StringBuffer sb = new StringBuffer();
+		this.decimalModeFlag = decimalModeFlag;
-    	sb.append("(N:" + (getNegativeFlag() ? '1' : '0') + ", ");
+	}
-    	sb.append("V:" + (getOverflowFlag() ? '1' : '0') + ", ");
+
-    	sb.append("B:" + (getBreakFlag() ? '1' : '0') + ", ");
+	/**
-    	sb.append("D:" + (getDecimalModeFlag() ? '1' : '0') + ", ");
+	 * Sets the Decimal Mode Flag to true.
-    	sb.append("I:" + (getIrqDisableFlag() ? '1' : '0') + ", ");
+	 */
-    	sb.append("Z:" + (getZeroFlag() ? '1' : '0') + ", ");
+	public void setDecimalModeFlag() {
-    	sb.append("C:" + (getCarryFlag() ? '1' : '0') + ")");
+		this.decimalModeFlag = true;
-    	return sb.toString();
+	}
-    }
+
+	/**
+	 * Clears the Decimal Mode Flag.
+	 */
+	public void clearDecimalModeFlag() {
+		this.decimalModeFlag = false;
+	}
+
+	/**
+	 * @return the break flag
+	 */
+	public boolean getBreakFlag() {
+		return breakFlag;
+	}
+
+	/**
+	 * @param breakFlag the break flag to set
+	 */
+	public void setBreakFlag(boolean breakFlag) {
+		this.breakFlag = breakFlag;
+	}
+
+	/**
+	 * Sets the Break Flag
+	 */
+	public void setBreakFlag() {
+		this.breakFlag = true;
+	}
+
+	/**
+	 * Clears the Break Flag
+	 */
+	public void clearBreakFlag() {
+		this.breakFlag = false;
+	}
+
+	/**
+	 * @return the overflow flag
+	 */
+	public boolean getOverflowFlag() {
+		return overflowFlag;
+	}
+
+	/**
+	 * @param overflowFlag the overflow flag to set
+	 */
+	public void setOverflowFlag(boolean overflowFlag) {
+		this.overflowFlag = overflowFlag;
+	}
+
+	/**
+	 * Sets the Overflow Flag
+	 */
+	public void setOverflowFlag() {
+		this.overflowFlag = true;
+	}
+
+	/**
+	 * Clears the Overflow Flag
+	 */
+	public void clearOverflowFlag() {
+		this.overflowFlag = false;
+	}
+
+	public int getAccumulator() {
+		return a;
+	}
+
+	public void setAccumulator(int val) {
+		this.a = val;
+	}
+
+	public int getXRegister() {
+		return x;
+	}
+
+	public void setXRegister(int val) {
+		this.x = val;
+	}
+
+	public int getYRegister() {
+		return y;
+	}
+
+	public void setYRegister(int val) {
+		this.y = val;
+	}
+
+	public int getProgramCounter() {
+		return pc;
+	}
+
+	public void setProgramCounter(int addr) {
+		this.pc = addr;
+	}
+
+	/**
+	 * @return A string representing the current status register state.
+	 */
+	public String statusRegisterString() {
+		StringBuffer sb = new StringBuffer();
+		sb.append("(N:" + (getNegativeFlag() ? '1' : '0') + ", ");
+		sb.append("V:" + (getOverflowFlag() ? '1' : '0') + ", ");
+		sb.append("B:" + (getBreakFlag() ? '1' : '0') + ", ");
+		sb.append("D:" + (getDecimalModeFlag() ? '1' : '0') + ", ");
+		sb.append("I:" + (getIrqDisableFlag() ? '1' : '0') + ", ");
+		sb.append("Z:" + (getZeroFlag() ? '1' : '0') + ", ");
+		sb.append("C:" + (getCarryFlag() ? '1' : '0') + ")");
+		return sb.toString();
+	}
 
 	/**
 	 * Returns a string representing the CPU state.

src/test/java/com/loomcom/symon/CpuImmediateModeTest.java

@@ -159,147 +159,99 @@ public class CpuImmediateModeTest extends TestCase {
 
 	/* ADC Immediate Mode Tests - 0x69 */
 
-	public void test_ADC_SetsAccumulator() {
+	public void test_ADC() {
-		bus.loadProgram(0x69, 0x01,  // ADC #$01
+		bus.loadProgram(0xa9, 0x00,  // LDA #$00
-										0x69, 0xa0,  // ADC #$a0
+										0x69, 0x01); // ADC #$01
-										0x69, 0x02,  // ADC #$02
+		cpu.step(2);
-										0x69, 0x06); // ADC #$06
-
-		cpu.step();
 		assertEquals(0x01, cpu.getAccumulator());
+		assertFalse(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertFalse(cpu.getCarryFlag());
 
-		cpu.step();
+		cpu.reset();
-		assertEquals(0xa1, cpu.getAccumulator());
+		bus.loadProgram(0xa9, 0x7f,  // LDA #$7f
+										0x69, 0x01); // ADC #$01
+		cpu.step(2);
+		assertEquals(0x80, cpu.getAccumulator());
+		assertTrue(cpu.getNegativeFlag());
+		assertTrue(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertFalse(cpu.getCarryFlag());
 
-		cpu.step();
+		cpu.reset();
-		assertEquals(0xa3, cpu.getAccumulator());
+		bus.loadProgram(0xa9, 0x80,  // LDA #$80
+										0x69, 0x01); // ADC #$01
+		cpu.step(2);
+		assertEquals(0x81, cpu.getAccumulator());
+		assertTrue(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertFalse(cpu.getCarryFlag());
 
-		cpu.step();
+		cpu.reset();
-		assertEquals(0xa9, cpu.getAccumulator());
+		bus.loadProgram(0xa9, 0xff,  // LDA #$ff
+										0x69, 0x01); // ADC #$01
+		cpu.step(2);
+		assertEquals(0x00, cpu.getAccumulator());
+		assertFalse(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertTrue(cpu.getZeroFlag());
+		assertTrue(cpu.getCarryFlag());
+
+		cpu.reset();
+		bus.loadProgram(0xa9, 0x00,  // LDA #$00
+										0x69, 0xff); // ADC #$ff
+		cpu.step(2);
+		assertEquals(0xff, cpu.getAccumulator());
+		assertTrue(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertFalse(cpu.getCarryFlag());
+
+		cpu.reset();
+		bus.loadProgram(0xa9, 0x7f,  // LDA #$7f
+										0x69, 0xff); // ADC #$ff
+		cpu.step(2);
+		assertEquals(0x7e, cpu.getAccumulator());
+		assertFalse(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertTrue(cpu.getCarryFlag());
+
+		cpu.reset();
+		bus.loadProgram(0xa9, 0x80,  // LDA #$80
+										0x69, 0xff); // ADC #$ff
+		cpu.step(2);
+		assertEquals(0x7f, cpu.getAccumulator());
+		assertFalse(cpu.getNegativeFlag());
+		assertTrue(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertTrue(cpu.getCarryFlag());
+
+		cpu.reset();
+		bus.loadProgram(0xa9, 0xff,  // LDA #$ff
+										0x69, 0xff); // ADC #$ff
+		cpu.step(2);
+		assertEquals(0xfe, cpu.getAccumulator());
+		assertTrue(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertTrue(cpu.getCarryFlag());
 	}
 
 	public void test_ADC_IncludesCarry() {
-		cpu.setCarryFlag(true);
+		bus.loadProgram(0xa9, 0x00,  // LDA #$01
-
+										0x38,        // SEC
-		bus.loadProgram(0x69, 0x01); // ADC #$01
+										0x69, 0x01); // ADC #$01
-
+		cpu.step(3);
-		cpu.step();
 		assertEquals(0x02, cpu.getAccumulator());
-	}
+		assertFalse(cpu.getNegativeFlag());
-
-	public void test_ADC_SetsCarryIfResultCarries() {
-		bus.loadProgram(0xa9, 0xff,  // LDA #$FE
-										0x69, 0x02);
-
-		cpu.step(2);
-
-		assertEquals(0x01, cpu.getAccumulator());
-		assertFalse(cpu.getZeroFlag());
-		assertTrue(cpu.getCarryFlag());
 		assertFalse(cpu.getOverflowFlag());
-	}
-
-	public void test_ADC_SetsOverflowIfResultChangesSign() {
-		bus.loadProgram(0xa9, 0x7f,  // LDA #$7f
-										0x69, 0x01); // ADC #$01
-
-		cpu.step(2);
-
-		assertEquals(0x80, cpu.getAccumulator());
 		assertFalse(cpu.getZeroFlag());
 		assertFalse(cpu.getCarryFlag());
-		assertTrue(cpu.getOverflowFlag());
-
-		cpu.reset();
-
-		bus.loadProgram(0xa9, 0x80,  // LDA #$80
-										0x69, 0xff); // ADC #$ff
-
-		cpu.step(2);
-
-		assertEquals(0x7f, cpu.getAccumulator());
-		assertFalse(cpu.getZeroFlag());
-		assertTrue(cpu.getCarryFlag());
-		assertFalse(cpu.getNegativeFlag());
-		assertTrue(cpu.getOverflowFlag());
 	}
 
-	public void test_ADC_DoesNotSetOverflowIfNotNeeded() {
-		bus.loadProgram(0xa9, 0xff,  // LDA #$ff
-										0x69, 0x01); // ADC #$01
-
-		cpu.step(2);
-
-		assertEquals(0x00, cpu.getAccumulator());
-		assertTrue(cpu.getZeroFlag());
-		assertTrue(cpu.getCarryFlag());
-		assertFalse(cpu.getNegativeFlag());
-		assertFalse(cpu.getOverflowFlag());
-
-		cpu.reset();
-
-		bus.loadProgram(0xa9, 0x01,  // LDA #$01
-										0x69, 0x01); // ADC #$01
-
-		cpu.step(2);
-		assertEquals(0x02, cpu.getAccumulator());
-		assertFalse(cpu.getZeroFlag());
-		assertFalse(cpu.getCarryFlag());
-		assertFalse(cpu.getNegativeFlag());
-		assertFalse(cpu.getOverflowFlag());
-	}
-
-	public void test_ADC_SetsNegativeFlagIfResultIsNegative() {
-		bus.loadProgram(0xa9, 0x7f,  // LDA #$7F
-										0x69, 0x01); // ADC #$01
-
-		cpu.step(2);
-
-		assertEquals(0x80, cpu.getAccumulator());
-		assertFalse(cpu.getZeroFlag());
-		assertFalse(cpu.getCarryFlag());
-		assertTrue(cpu.getNegativeFlag());
-		assertTrue(cpu.getOverflowFlag());
-	}
-
-	public void test_ADC_SetsZeroFlagIfResultIsZero() {
-		bus.loadProgram(0xa9, 0xff,  // LDA #$FF
-										0x69, 0x01); // ADC #$01
-
-		cpu.step(2);
-
-		assertEquals(0x00, cpu.getAccumulator());
-		assertTrue(cpu.getZeroFlag());
-		assertTrue(cpu.getCarryFlag());
-		assertFalse(cpu.getNegativeFlag());
-		assertFalse(cpu.getOverflowFlag());
-	}
-
-	public void test_ADC_DoesNotSetNegativeFlagIfResultNotNegative() {
-		bus.loadProgram(0xa9, 0x7e,  // LDA #$7E
-										0x69, 0x01); // ADC #$01
-
-		cpu.step(2);
-
-		assertEquals(0x7f, cpu.getAccumulator());
-		assertFalse(cpu.getZeroFlag());
-		assertFalse(cpu.getCarryFlag());
-		assertFalse(cpu.getNegativeFlag());
-		assertFalse(cpu.getOverflowFlag());
-	}
-
-	public void test_ADC_DoesNotSetZeroFlagIfResultNotZero() {
-		bus.loadProgram(0xa9, 0xff,  // LDA #$ff
-										0x69, 0x03); // ADC #$03
-
-		cpu.step(2);
-
-		assertEquals(0x2, cpu.getAccumulator());
-		assertFalse(cpu.getZeroFlag());
-		assertTrue(cpu.getCarryFlag());
-		assertFalse(cpu.getNegativeFlag());
-		assertFalse(cpu.getOverflowFlag());
-	}
 
 	/* LDY Immediate Mode Tests - 0xa0 */
 
@@ -612,29 +564,63 @@ public class CpuImmediateModeTest extends TestCase {
 
 	/* SBC Immediate Mode Tests - 0xe9 */
 
-	public void test_SBC_SetsAccumulator() {
+	public void test_SBC() {
-		bus.loadProgram(0xa9, 0xff,  // LDA #$FF
+		bus.loadProgram(0xa9, 0x00,  // LDA #$00
-										0xe9, 0x01,  // SBC #$01
+										0xe9, 0x01); // SBC #$01
-										0xe9, 0x01,  // SBC #$a0
+		cpu.step(2);
-										0xe9, 0x01,  // SBC #$02
+		assertEquals(0xfe, cpu.getAccumulator());
-										0xe9, 0x01); // SBC #$06
+		assertTrue(cpu.getNegativeFlag());
-
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
 		assertFalse(cpu.getCarryFlag());
+
+		cpu.reset();
+		bus.loadProgram(0xa9, 0x7f,  // LDA #$7f
+										0xe9, 0x01); // SBC #$01
+		cpu.step(2);
+		assertEquals(0x7d, cpu.getAccumulator());
+		assertFalse(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertTrue(cpu.getCarryFlag());
+
+		cpu.reset();
+		bus.loadProgram(0xa9, 0x80,  // LDA #$80
+										0xe9, 0x01); // SBC #$01
+		cpu.step(2);
+		assertEquals(0x7e, cpu.getAccumulator());
+		assertFalse(cpu.getNegativeFlag());
+		assertTrue(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
+		assertTrue(cpu.getCarryFlag());
+
+		cpu.reset();
+		bus.loadProgram(0xa9, 0xff,  // LDA #$ff
+										0xe9, 0x01); // SBC #$01
 		cpu.step(2);
 		assertEquals(0xfd, cpu.getAccumulator());
+		assertTrue(cpu.getNegativeFlag());
+		assertFalse(cpu.getOverflowFlag());
+		assertFalse(cpu.getZeroFlag());
 		assertTrue(cpu.getCarryFlag());
 
-		cpu.step();
+		cpu.reset();
-		assertEquals(0xfc, cpu.getAccumulator());
+		bus.loadProgram(0xa9, 0x02,  // LDA #$02
-		assertTrue(cpu.getCarryFlag());
+										0xe9, 0x01); // SBC #$01
-
+		cpu.step(2);
-		cpu.step();
+		assertEquals(0x00, cpu.getAccumulator());
-		assertEquals(0xfb, cpu.getAccumulator());
+		assertFalse(cpu.getNegativeFlag());
-		assertTrue(cpu.getCarryFlag());
+		assertFalse(cpu.getOverflowFlag());
-
+		assertTrue(cpu.getZeroFlag());
-		cpu.step();
-		assertEquals(0xfa, cpu.getAccumulator());
 		assertTrue(cpu.getCarryFlag());
 	}
 
+	public void test_SBC_IncludesNotOfCarry() {
+		cpu.reset();
+		bus.loadProgram(0x38,        // SEC
+										0xa9, 0x00,  // LDA #$00
+										0xe9, 0x01); // SBC #$01
+		cpu.step(3);
+		assertEquals(0xff, cpu.getAccumulator());
+	}
 }