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Some API changes, lots of test changes.

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This commit is contained in:
Seth J. Morabito 2008-12-14 23:43:04 -08:00
parent 6443cacdb9
commit 1bd59b048b
4 changed files with 167 additions and 98 deletions
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14
src/main/java/com/loomcom/symon/Bus.java
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@ -63,7 +63,7 @@ public class Bus {
* device.
*/
public boolean isComplete() {
// Emtpy maps cannot be complete.
// Empty maps cannot be complete.
if (devices.isEmpty()) { return false; }
// Loop over devices and ensure they are contiguous.
@ -129,4 +129,16 @@ public class Bus {
// Expose a copy of the device list, not the original
return new TreeSet<Device>(devices);
}
public Cpu getCpu() {
return cpu;
}
public void loadProgram(int... program) {
int address = getCpu().getProgramCounter();
int i = 0;
for (int d : program) {
write(address + i++, d);
}
}
}

76
src/main/java/com/loomcom/symon/Cpu.java
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@ -6,6 +6,8 @@ import java.util.Arrays;
* Main 6502 CPU Simulation.
*/
public class Cpu implements InstructionTable {
public static final int DEFAULT_BASE_ADDRESS = 0x200;
/* The Bus */
private Bus bus;
@ -75,6 +77,12 @@ public class Cpu implements InstructionTable {
overflowFlag = false;
}
public void step(int num) {
for (int i = 0; i < num; i++) {
step();
}
}
/**
* Performs an individual machine cycle.
*/
@ -123,8 +131,7 @@ public class Cpu implements InstructionTable {
break;
case 0x09: // ORA - Immediate
a |= operands[0];
setZeroFlag(a);
setNegativeFlag(a);
setArithmeticFlags(a);
break;
case 0x0a: // n/a
break;
@ -192,8 +199,7 @@ public class Cpu implements InstructionTable {
break;
case 0x29: // n/a
a &= operands[0];
setZeroFlag(a);
setNegativeFlag(a);
setArithmeticFlags(a);
break;
case 0x2a: // n/a
break;
@ -261,8 +267,7 @@ public class Cpu implements InstructionTable {
break;
case 0x49: // EOR - Immediate
a ^= operands[0];
setZeroFlag(a);
setNegativeFlag(a);
setArithmeticFlags(a);
break;
case 0x4a: // n/a
break;
@ -330,19 +335,8 @@ public class Cpu implements InstructionTable {
case 0x68: // n/a
break;
case 0x69: // ADC - Immediate Mode
boolean sign = (a < 0x80);
a += (operands[0] + (carryFlag ? 1 : 0));
// Result overflowed a byte
if (a > 0xff) {
a &= 0xff;
setCarryFlag(true);
}
// Sign changed
if (sign != a < 0x80) {
setOverflowFlag(true);
}
setZeroFlag(a);
setNegativeFlag(a);
a = adc(a, operands[0]);
setArithmeticFlags(a);
break;
case 0x6a: // n/a
break;
@ -458,15 +452,13 @@ public class Cpu implements InstructionTable {
case 0xa0: // LDY - Immediate
y = operands[0];
setZeroFlag(y);
setNegativeFlag(y);
setArithmeticFlags(y);
break;
case 0xa1: // n/a
break;
case 0xa2: // LDX - Immediate
x = operands[0];
setZeroFlag(x);
setNegativeFlag(x);
setArithmeticFlags(x);
break;
case 0xa3: // n/a
break;
@ -482,8 +474,7 @@ public class Cpu implements InstructionTable {
break;
case 0xa9: // LDA - Immediate
a = operands[0];
setZeroFlag(a);
setNegativeFlag(a);
setArithmeticFlags(a);
break;
case 0xaa: // n/a
break;
@ -664,7 +655,34 @@ public class Cpu implements InstructionTable {
break;
}
}
/**
* Add with Carry, used by all addressing mode implementations of ADC.
* As a side effect, this will set the
*
* @param acc The current value of the accumulator
* @param operand The operand
* @return
*/
public int adc(int acc, int operand) {
int result = operand + a + (carryFlag ? 1 : 0);
int carry = (operand & 0x7f) + (a & 0x7f) + (carryFlag ? 1 : 0);
if (result > 0xff) { setCarryFlag(true); }
result = result & 0xff;
setOverflowFlag(carryFlag ^ ((carry & 0x80) != 0));
return result;
}
/**
* Set the Negative and Zero flags based on the current value of the
* register operand.
*
* @param reg The register.
*/
public void setArithmeticFlags(int reg) {
zeroFlag = (reg == 0);
negativeFlag = (reg & 0x80) != 0;
}
/**
* @return the negative flag
*/
@ -676,7 +694,6 @@ public class Cpu implements InstructionTable {
* @param register the register value to test for negativity
*/
public void setNegativeFlag(int register) {
this.negativeFlag = (((register>>>7)&0xff) == 1);
}
/**
@ -707,13 +724,6 @@ public class Cpu implements InstructionTable {
return zeroFlag;
}
/**
* @param register the register to test for zero
*/
public void setZeroFlag(int register) {
this.zeroFlag = (register == 0);
}
/**
* @param zeroFlag the zero flag to set
*/

2
src/main/java/com/loomcom/symon/Simulator.java
View File

@ -55,7 +55,7 @@ public class Simulator {
int i = 0;
for (int d : program) {
bus.write(address + i, program[i++]);
bus.write(address + i++, d);
}
}

173
src/test/java/com/loomcom/symon/CpuImmediateModeTests.java
View File

@ -2,15 +2,14 @@ package com.loomcom.symon;
import com.loomcom.symon.devices.Memory;
import com.loomcom.symon.exceptions.MemoryRangeException;
import junit.framework.TestCase;
import junit.framework.*;
public class CpuImmediateModeTests extends TestCase {
private Cpu cpu;
private Bus bus;
private Memory mem;
protected Cpu cpu;
protected Bus bus;
protected Memory mem;
public void setUp() throws MemoryRangeException {
this.cpu = new Cpu();
this.bus = new Bus(0x0000, 0xffff);
@ -18,71 +17,62 @@ public class CpuImmediateModeTests extends TestCase {
bus.addCpu(cpu);
bus.addDevice(mem);
// All test programs start at 0x0200;
bus.write(0xfffc, 0x00);
bus.write(0xfffd, 0x02);
// Load the reset vector.
bus.write(0xfffc, Cpu.DEFAULT_BASE_ADDRESS & 0x00ff);
bus.write(0xfffd, (Cpu.DEFAULT_BASE_ADDRESS & 0xff00)>>>8);
cpu.reset();
}
/* ORA Immediate Mode Tests - 0x09 */
public void test_ORA_SetsAccumulator() {
bus.write(0x0200, 0x09); // ORA #$00
bus.write(0x0201, 0x00);
bus.loadProgram(0x09, 0x00, // ORA #$00
0x09, 0x11, // ORA #$11
0x09, 0x22, // ORA #$22
0x09, 0x44, // ORA #$44
0x09, 0x88); // ORA #$88
cpu.step();
// 0x00 | 0x00 == 0x00
assertEquals(0x00, cpu.getAccumulator());
bus.write(0x0202, 0x09); // ORA #$11
bus.write(0x0203, 0x11);
cpu.step();
// 0x00 | 0x11 == 0x11
assertEquals(0x11, cpu.getAccumulator());
bus.write(0x0204, 0x09); // ORA #$22
bus.write(0x0205, 0x22);
cpu.step();
// 0x11 | 0x22 == 0x33
assertEquals(0x33, cpu.getAccumulator());
bus.write(0x0206, 0x09); // ORA #$44
bus.write(0x0207, 0x44);
cpu.step();
// 0x33 | 0x44 == 0x77
assertEquals(0x77, cpu.getAccumulator());
bus.write(0x0208, 0x09); // ORA #$88
bus.write(0x0209, 0x88);
cpu.step();
// 0x77 | 0x88 == 0xFF
assertEquals(0xff, cpu.getAccumulator());
}
public void test_ORA_SetsZeroFlagIfResultIsZero() {
bus.write(0x0200, 0x09); // ORA #$00
bus.write(0x0201, 0x00);
bus.loadProgram(0x09, 0x00); // ORA #$00
cpu.step();
assertTrue(cpu.getZeroFlag());
}
public void test_ORA_DoesNotSetZeroFlagIfResultNotZero() {
bus.write(0x0200, 0x09); // ORA #$01
bus.write(0x0201, 0x01);
bus.loadProgram(0x09, 0x01); // ORA #$01
cpu.step();
assertFalse(cpu.getZeroFlag());
}
public void test_ORA_SetsNegativeFlagIfResultIsNegative() {
bus.write(0x0200, 0x09); // ORA #$80
bus.write(0x0201, 0x80);
bus.loadProgram(0x09, 0x80); // ORA #$80
cpu.step();
assertTrue(cpu.getNegativeFlag());
}
public void test_ORA_DoesNotSetNegativeFlagIfResultNotNegative() {
bus.write(0x0200, 0x09); // ORA #$7F
bus.write(0x0201, 0x7f);
bus.loadProgram(0x09, 0x7f); // ORA #$7F
cpu.step();
assertFalse(cpu.getNegativeFlag());
}
@ -138,58 +128,57 @@ public class CpuImmediateModeTests extends TestCase {
}
public void test_AND_DoesNotSetZeroFlagIfResultNotZero() {
bus.write(0x0200, 0xa9); // LDA #$88
bus.write(0x0201, 0x88);
cpu.step();
bus.write(0x0202, 0x29); // AND #$f1
bus.write(0x0203, 0xf1);
cpu.step();
bus.loadProgram(0xa9, 0x88, // LDA #$88
0x29, 0xf1); // AND #$F1
cpu.step(2);
assertFalse(cpu.getZeroFlag());
}
public void test_AND_SetsNegativeFlagIfResultIsNegative() {
bus.write(0x0200, 0xa9); // LDA #$88
bus.write(0x0201, 0x88);
cpu.step();
bus.write(0x0202, 0x29); // AND #$F0
bus.write(0x0203, 0xf0);
cpu.step();
bus.loadProgram(0xa9, 0x88, // LDA #$88
0x29, 0xf0); // AND #$F0
cpu.step(2);
assertTrue(cpu.getNegativeFlag());
}
public void test_AND_DoesNotSetNegativeFlagIfResultNotNegative() {
bus.write(0x0200, 0xa9); // LDA #$88
bus.write(0x0201, 0x88);
cpu.step();
bus.write(0x0202, 0x29); // AND #$0F
bus.write(0x0203, 0x0f);
cpu.step();
bus.loadProgram(0xa9, 0x88, // LDA #$88
0x29, 0x0f); // AND #$0F
cpu.step(2);
assertFalse(cpu.getNegativeFlag());
}
/* EOR Immediate Mode Tests - 0x49 */
public void test_EOR_SetsAccumulator() {
bus.write(0x0200, 0xa9); // LDA #$88
bus.write(0x0201, 0x88);
bus.loadProgram(0xa9, 0x88, // LDA #$88
0x49, 0x00, // EOR #$00
0x49, 0xff, // EOR #$ff
0x49, 0x33); // EOR #$33
cpu.step();
bus.write(0x0202, 0x49); // EOR #$00
bus.write(0x0203, 0x00);
cpu.step();
assertEquals(0x88, cpu.getAccumulator());
bus.write(0x0204, 0x49); // EOR #$ff
bus.write(0x0205, 0xff);
cpu.step();
assertEquals(0x77, cpu.getAccumulator());
bus.write(0x0206, 0x49); // EOR #$33
bus.write(0x0207, 0x33);
cpu.step();
assertEquals(0x44, cpu.getAccumulator());
}
public void test_EOR_SetsArithmeticFlags() {
bus.loadProgram(0xa9, 0x77, // LDA #$77
0x49, 0x77, // EOR #$77
0x49, 0xff); // EOR #$ff
cpu.step();
cpu.step();
assertEquals(0x00, cpu.getAccumulator());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
cpu.step();
assertEquals(0xff, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
/* ADC Immediate Mode Tests - 0x69 */
public void test_ADC_SetsAccumulator() {
@ -222,7 +211,7 @@ public class CpuImmediateModeTests extends TestCase {
assertEquals(0x02, cpu.getAccumulator());
}
public void test_ADC_SetsCarryIfResultOverflows() {
public void test_ADC_SetsCarryIfResultCarries() {
bus.write(0x200, 0xa9); // LDA #$fe
bus.write(0x201, 0xff);
cpu.step();
@ -231,7 +220,9 @@ public class CpuImmediateModeTests extends TestCase {
cpu.step();
// $ff + $02 = $101 = [c] + $01
assertEquals(0x01, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getCarryFlag());
assertFalse(cpu.getOverflowFlag());
}
public void test_ADC_SetsOverflowIfResultChangesSign() {
@ -242,7 +233,51 @@ public class CpuImmediateModeTests extends TestCase {
bus.write(0x203, 0x01);
cpu.step();
assertEquals(0x80, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getCarryFlag());
assertTrue(cpu.getOverflowFlag());
cpu.reset();
bus.write(0x200, 0xa9); // LDA #$80
bus.write(0x201, 0x80);
cpu.step();
bus.write(0x202, 0x69); // ADC #$ff
bus.write(0x203, 0xff);
cpu.step();
assertEquals(0x7f, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getCarryFlag());
assertFalse(cpu.getNegativeFlag());
assertTrue(cpu.getOverflowFlag());
}
public void test_ADC_DoesNotSetOverflowIfNotNeeded() {
bus.write(0x200, 0xa9); // LDA #$ff
bus.write(0x201, 0xff);
cpu.step();
bus.write(0x202, 0x69); // ADC #$01
bus.write(0x203, 0x01);
cpu.step();
assertEquals(0x00, cpu.getAccumulator());
assertTrue(cpu.getZeroFlag());
assertTrue(cpu.getCarryFlag());
assertFalse(cpu.getNegativeFlag());
assertFalse(cpu.getOverflowFlag());
cpu.reset();
bus.write(0x200, 0xa9); // LDA #$01
bus.write(0x201, 0x01);
cpu.step();
bus.write(0x202, 0x69); // ADC #$01
bus.write(0x203, 0x01);
cpu.step();
assertEquals(0x02, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getCarryFlag());
assertFalse(cpu.getNegativeFlag());
assertFalse(cpu.getOverflowFlag());
}
public void test_ADC_SetsNegativeFlagIfResultIsNegative() {
@ -253,9 +288,12 @@ public class CpuImmediateModeTests extends TestCase {
bus.write(0x203, 0x01);
cpu.step();
assertEquals(0x80, cpu.getAccumulator());
assertTrue(cpu.getNegativeFlag());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getCarryFlag());
assertTrue(cpu.getNegativeFlag());
assertTrue(cpu.getOverflowFlag());
}
public void test_ADC_SetsZeroFlagIfResultIsZero() {
bus.write(0x200, 0xa9); // LDA #$ff
bus.write(0x201, 0xff);
@ -264,7 +302,10 @@ public class CpuImmediateModeTests extends TestCase {
bus.write(0x203, 0x01);
cpu.step();
assertEquals(0x00, cpu.getAccumulator());
assertTrue(cpu.getZeroFlag());
assertTrue(cpu.getZeroFlag());
assertTrue(cpu.getCarryFlag());
assertFalse(cpu.getNegativeFlag());
assertFalse(cpu.getOverflowFlag());
}
public void test_ADC_DoesNotSetNegativeFlagIfResultNotNegative() {
@ -275,7 +316,10 @@ public class CpuImmediateModeTests extends TestCase {
bus.write(0x203, 0x01);
cpu.step();
assertEquals(0x7f, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getCarryFlag());
assertFalse(cpu.getNegativeFlag());
assertFalse(cpu.getOverflowFlag());
}
public void test_ADC_DoesNotSetZeroFlagIfResultNotZero() {
@ -286,7 +330,10 @@ public class CpuImmediateModeTests extends TestCase {
bus.write(0x203, 0x03);
cpu.step();
assertEquals(0x2, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getCarryFlag());
assertFalse(cpu.getNegativeFlag());
assertFalse(cpu.getOverflowFlag());
}
/* LDY Immediate Mode Tests - 0xa0 */