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Implemented Relative mode (branch) instructions and unit tests. Fixed

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a bug in the instruction size table.
This commit is contained in:
Seth Morabito 2009-01-07 18:26:11 -08:00
parent f21a0d76e9
commit ed943687bf
3 changed files with 321 additions and 9 deletions
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48
src/main/java/com/loomcom/symon/Cpu.java
View File

@ -188,7 +188,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(k);
break;
case 0x10: // TODO: implement
case 0x10: // BPL - Branch if Positive - Relative
if (!getNegativeFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0x11: // TODO: implement
break;
@ -277,7 +280,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(k);
break;
case 0x30: // TODO: implement
case 0x30: // BMI - Branch if Minus - Relative
if (getNegativeFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0x31: // TODO: implement
break;
@ -356,7 +362,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(k);
break;
case 0x50: // TODO: implement
case 0x50: // BVC - Branch if Overflow Clear - Relative
if (!getOverflowFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0x51: // TODO: implement
break;
@ -459,7 +468,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(k);
break;
case 0x70: // TODO: implement
case 0x70: // BVS - Branch if Overflow Set - Relative
if (getOverflowFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0x71: // TODO: implement
break;
@ -538,7 +550,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(x);
break;
case 0x90: // TODO: implement
case 0x90: // BCC - Branch if Carry Clear - Relative
if (!getCarryFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0x91: // TODO: implement
break;
@ -617,7 +632,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(x);
break;
case 0xb0: // TODO: implement
case 0xb0: // BCS - Branch if Carry Set - Relative
if (getCarryFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0xb1: // TODO: implement
break;
@ -698,7 +716,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(k);
break;
case 0xd0: // TODO: implement
case 0xd0: // BNE - Branch if Not Equal to Zero - Relative
if (!getZeroFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0xd1: // TODO: implement
break;
@ -781,7 +802,10 @@ public class Cpu implements InstructionTable {
setArithmeticFlags(k);
break;
case 0xf0: // TODO: implement
case 0xf0: // BEQ - Branch if Equal to Zero - Relative
if (getZeroFlag()) {
pc = relAddress(operands[0]);
}
break;
case 0xf1: // TODO: implement
break;
@ -1562,6 +1586,14 @@ public class Cpu implements InstructionTable {
return (zp+getXRegister())&0xff;
}
/**
* Given a single byte, compute the offset address.
*/
int relAddress(int offset) {
// Cast the offset to a signed byte to handle negative offsets
return (pc + (byte)offset) & 0xffff;
}
/**
* Given a single byte, compute the Zero Page,Y offset address.
*/

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

@ -217,7 +217,7 @@ public interface InstructionTable {
2, 2, 0, 0, 2, 2, 2, 0, 1, 0, 1, 0, 3, 3, 3, 0,
2, 2, 0, 0, 2, 2, 2, 0, 1, 3, 1, 0, 0, 3, 0, 0,
2, 2, 2, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
0, 2, 0, 0, 2, 2, 2, 0, 1, 3, 1, 0, 3, 3, 3, 0,
2, 2, 0, 0, 2, 2, 2, 0, 1, 3, 1, 0, 3, 3, 3, 0,
2, 2, 0, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
2, 2, 0, 0, 0, 2, 2, 0, 1, 3, 0, 0, 0, 3, 3, 0,
2, 2, 0, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,

280
src/test/java/com/loomcom/symon/CpuRelativeModeTest.java Normal file
View File

@ -0,0 +1,280 @@
package com.loomcom.symon;
import com.loomcom.symon.devices.Memory;
import com.loomcom.symon.exceptions.MemoryRangeException;
import junit.framework.TestCase;
public class CpuRelativeModeTest extends TestCase {
protected Cpu cpu;
protected Bus bus;
protected Memory mem;
protected void setUp() throws Exception {
this.cpu = new Cpu();
this.bus = new Bus(0x0000, 0xffff);
this.mem = new Memory(0x0000, 0x10000);
bus.addCpu(cpu);
bus.addDevice(mem);
// Load the reset vector.
bus.write(0xfffc, Cpu.DEFAULT_BASE_ADDRESS & 0x00ff);
bus.write(0xfffd, (Cpu.DEFAULT_BASE_ADDRESS & 0xff00)>>>8);
cpu.reset();
// Assert initial state
assertEquals(0, cpu.getAccumulator());
assertEquals(0, cpu.getXRegister());
assertEquals(0, cpu.getYRegister());
assertEquals(0x200, cpu.getProgramCounter());
assertEquals(0xff, cpu.getStackPointer());
assertEquals(0x20, cpu.getProcessorStatus());
}
/*
* The following opcodes are tested for correctness in this file:
*
* BPL - Branch if Positive - 0x10
* BMI - Branch if Minus - 0x30
* BVC - Branch if Overflow Clear - 0x50
* BVS - Branch if Overflow Set - 0x70
* BCC - Branch if Carry Clear - 0x90
* BCS - Branch if Carry Set - 0xb0
* BNE - Branch if Not Equal to Zero - 0xd0
* BEQ - Branch if Equal to Zero - 0xf0
*
*/
/* BPL - Branch if Positive - 0x10 */
public void test_BPL() {
// Positive Offset
bus.loadProgram(0x10, 0x05); // BPL $05 ; *=$0202+$05 ($0207)
cpu.setNegativeFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x10, 0x05); // BPL $05 ; *=$0202+$05 ($0207)
cpu.clearNegativeFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0x10, 0xfb); // BPL $fb ; *=$0202-$05 ($01fd)
cpu.setNegativeFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x10, 0xfb); // BPL $fb ; *=$0202-$05 ($01fd)
cpu.clearNegativeFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
}
/* BMI - Branch if Minus - 0x30 */
public void test_BMI() {
// Positive Offset
bus.loadProgram(0x30, 0x05); // BMI $05 ; *=$0202+$05 ($0207)
cpu.setNegativeFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x30, 0x05); // BMI $05 ; *=$0202+$05 ($0207)
cpu.clearNegativeFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0x30, 0xfb); // BMI $fb ; *=$0202-$05 ($01fd)
cpu.setNegativeFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x30, 0xfb); // BMI $fb ; *=$0202-$05 ($01fd)
cpu.clearNegativeFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
}
/* BVC - Branch if Overflow Clear - 0x50 */
public void test_BVC() {
// Positive Offset
bus.loadProgram(0x50, 0x05); // BVC $05 ; *=$0202+$05 ($0207)
cpu.setOverflowFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x50, 0x05); // BVC $05 ; *=$0202+$05 ($0207)
cpu.clearOverflowFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0x50, 0xfb); // BVC $fb ; *=$0202-$05 ($01fd)
cpu.setOverflowFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x50, 0xfb); // BVC $fb ; *=$0202-$05 ($01fd)
cpu.clearOverflowFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
}
/* BVS - Branch if Overflow Set - 0x70 */
public void test_BVS() {
// Positive Offset
bus.loadProgram(0x70, 0x05); // BVS $05 ; *=$0202+$05 ($0207)
cpu.setOverflowFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x70, 0x05); // BVS $05 ; *=$0202+$05 ($0207)
cpu.clearOverflowFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0x70, 0xfb); // BVS $fb ; *=$0202-$05 ($01fd)
cpu.setOverflowFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x70, 0xfb); // BVS $fb ; *=$0202-$05 ($01fd)
cpu.clearOverflowFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
}
/* BCC - Branch if Carry Clear - 0x90 */
public void test_BCC() {
// Positive Offset
bus.loadProgram(0x90, 0x05); // BCC $05 ; *=$0202+$05 ($0207)
cpu.setCarryFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x90, 0x05); // BCC $05 ; *=$0202+$05 ($0207)
cpu.clearCarryFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0x90, 0xfb); // BCC $fb ; *=$0202-$05 ($01fd)
cpu.setCarryFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0x90, 0xfb); // BCC $fb ; *=$0202-$05 ($01fd)
cpu.clearCarryFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
}
/* BCS - Branch if Carry Set - 0xb0 */
public void test_BCS() {
// Positive Offset
bus.loadProgram(0xb0, 0x05); // BCS $05 ; *=$0202+$05 ($0207)
cpu.setCarryFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0xb0, 0x05); // BCS $05 ; *=$0202+$05 ($0207)
cpu.clearCarryFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0xb0, 0xfb); // BCS $fb ; *=$0202-$05 ($01fd)
cpu.setCarryFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0xb0, 0xfb); // BCS $fb ; *=$0202-$05 ($01fd)
cpu.clearCarryFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
}
/* BNE - Branch if Not Equal to Zero - 0xd0 */
public void test_BNE() {
// Positive Offset
bus.loadProgram(0xd0, 0x05); // BNE $05 ; *=$0202+$05 ($0207)
cpu.setZeroFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0xd0, 0x05); // BNE $05 ; *=$0202+$05 ($0207)
cpu.clearZeroFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0xd0, 0xfb); // BNE $fb ; *=$0202-$05 ($01fd)
cpu.setZeroFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0xd0, 0xfb); // BNE $fb ; *=$0202-$05 ($01fd)
cpu.clearZeroFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
}
/* BEQ - Branch if Equal to Zero - 0xf0 */
public void test_BEQ() {
// Positive Offset
bus.loadProgram(0xf0, 0x05); // BEQ $05 ; *=$0202+$05 ($0207)
cpu.setZeroFlag();
cpu.step();
assertEquals(0x207, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0xf0, 0x05); // BEQ $05 ; *=$0202+$05 ($0207)
cpu.clearZeroFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
// Negative Offset
cpu.reset();
bus.loadProgram(0xf0, 0xfb); // BEQ $fb ; *=$0202-$05 ($01fd)
cpu.setZeroFlag();
cpu.step();
assertEquals(0x1fd, cpu.getProgramCounter());
cpu.reset();
bus.loadProgram(0xf0, 0xfb); // BEQ $fb ; *=$0202-$05 ($01fd)
cpu.clearZeroFlag();
cpu.step();
assertEquals(0x202, cpu.getProgramCounter());
}
}