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

package com.loomcom.symon;

import com.loomcom.symon.devices.Memory;
import com.loomcom.symon.exceptions.MemoryAccessException;

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, 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(0x24, 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() throws MemoryAccessException {
        // 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() throws MemoryAccessException {
        // 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() throws MemoryAccessException {
        // 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() throws MemoryAccessException {
        // 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() throws MemoryAccessException {
        // 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() throws MemoryAccessException {
        // 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() throws MemoryAccessException {
        // 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() throws MemoryAccessException {
        // 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());
    }

}