package com.loomcom.symon;
import com.loomcom.symon.devices.Memory;
import com.loomcom.symon.exceptions.MemoryAccessException;
import junit.framework.TestCase;
public class CpuZeroPageYModeTest 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, 0xffff);
bus.addCpu(cpu);
bus.addDevice(mem);
// Load the reset vector.
bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
bus.write(0xfffd, (Bus.DEFAULT_LOAD_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:
*
* STX - $96
* LDX - $b6
*
*/
/* STX - Store X Register - $96 */
public void test_STX() throws MemoryAccessException {
cpu.setYRegister(0x30);
cpu.setXRegister(0x00);
bus.loadProgram(0x96, 0x10); // STX $10,Y
cpu.step();
assertEquals(0x00, bus.read(0x40));
// Should have no effect on flags.
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
cpu.reset();
cpu.setYRegister(0x30);
cpu.setXRegister(0x0f);
bus.loadProgram(0x96, 0x10); // STX $10,Y
cpu.step();
assertEquals(0x0f, bus.read(0x40));
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
cpu.reset();
cpu.setYRegister(0x30);
cpu.setXRegister(0x80);
bus.loadProgram(0x96, 0x10); // STX $10,Y
cpu.step();
assertEquals(0x80, bus.read(0x40));
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
/* LDX - Load X Register - $b6 */
public void test_LDX() throws MemoryAccessException {
bus.write(0x40, 0x00);
bus.write(0x41, 0x0f);
bus.write(0x42, 0x80);
bus.loadProgram(0xb6, 0x10,
0xb6, 0x11,
0xb6, 0x12);
cpu.setYRegister(0x30);
cpu.step();
assertEquals(0x00, cpu.getXRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
cpu.step();
assertEquals(0x0f, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
cpu.step();
assertEquals(0x80, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
}