package com.loomcom.symon;
import com.loomcom.symon.devices.Memory;
import com.loomcom.symon.exceptions.MemoryAccessException;
import com.loomcom.symon.exceptions.MemoryRangeException;
import org.junit.*;
import static org.junit.Assert.*;
public class CpuImpliedModeTest {
protected Cpu cpu;
protected Bus bus;
protected Memory mem;
@Before
public void setUp() throws MemoryRangeException, MemoryAccessException {
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:
*
* BRK - $00
* CLC - $18
* CLD - $d8
* CLI - $58
* CLV - $B8
*
* DEX - $ca
* DEY - $88
* INX - $e8
* INY - $c8
* NOP - $ea
*
* PHA - $48
* PHP - $08
* PLA - $68
* PLP - $28
* RTI - $40
*
* RTS - $60
* SEC - $38
* SED - $f8
* SEI - $78
* TAX - $aa
*
* TAY - $a8
* TSX - $ba
* TXA - $8a
* TXS - $9a
* TYA - $98
*/
/* BRK Tests - 0x00 */
@Test
public void test_BRK() throws MemoryAccessException {
cpu.setCarryFlag();
cpu.setOverflowFlag();
assertEquals(0x20 | Cpu.P_CARRY | Cpu.P_OVERFLOW,
cpu.getProcessorStatus());
assertEquals(0x00, cpu.stackPeek());
assertFalse(cpu.getBreakFlag());
assertEquals(0x0200, cpu.getProgramCounter());
assertEquals(0xff, cpu.getStackPointer());
// Set the IRQ vector
bus.write(0xffff, 0x12);
bus.write(0xfffe, 0x34);
bus.loadProgram(0xea, // NOP
0xea, // NOP
0xea, // NOP
0x00, // BRK
0xea, // NOP
0xea); // NOP
cpu.step(3); // Three NOP instructions
assertEquals(0x203, cpu.getProgramCounter());
cpu.step(); // Triggers the BRK
// Was at PC = 0x204. PC+1 should now be on the stack
assertEquals(0x02, bus.read(0x1ff)); // PC high byte
assertEquals(0x05, bus.read(0x1fe)); // PC low byte
assertEquals(0x20 | Cpu.P_CARRY | Cpu.P_OVERFLOW | Cpu.P_BREAK,
bus.read(0x1fd)); // Processor Status, with B set
// Interrupt vector held 0x1234, so we should be there.
assertEquals(0x1234, cpu.getProgramCounter());
assertEquals(0xfc, cpu.getStackPointer());
// B and I flags should have been set on P
assertEquals(0x20 | Cpu.P_CARRY | Cpu.P_OVERFLOW | Cpu.P_BREAK |
Cpu.P_IRQ_DISABLE,
cpu.getProcessorStatus());
}
@Test
public void test_BRK_HonorsIrqDisableFlag() throws MemoryAccessException {
cpu.setIrqDisableFlag();
bus.loadProgram(0xea,
0xea,
0xea,
0x00,
0xea,
0xea);
cpu.step(3); // Three NOP instructions
assertEquals(0x203, cpu.getProgramCounter());
// Triggers the BRK, which should do nothing because
// of the Interrupt Disable flag
cpu.step();
// Reset to original contents of PC
assertEquals(0x0204, cpu.getProgramCounter());
// Empty stack
assertEquals(0xff, cpu.getStackPointer());
cpu.step(2); // Two more NOPs
// Reset to original contents of PC
assertEquals(0x0206, cpu.getProgramCounter());
// Empty stack
assertEquals(0xff, cpu.getStackPointer());
}
/* CLC - Clear Carry Flag - $18 */
@Test
public void test_CLC() throws MemoryAccessException {
cpu.setCarryFlag();
assertTrue(cpu.getCarryFlag());
bus.loadProgram(0x18);
cpu.step();
assertFalse(cpu.getCarryFlag());
}
/* CLD - Clear Decimal Mode Flag - $d8 */
@Test
public void test_CLD() throws MemoryAccessException {
cpu.setDecimalModeFlag();
assertTrue(cpu.getDecimalModeFlag());
bus.loadProgram(0xd8);
cpu.step();
assertFalse(cpu.getDecimalModeFlag());
}
/* CLI - Clear Interrupt Disabled Flag - $58 */
@Test
public void test_CLI() throws MemoryAccessException {
cpu.setIrqDisableFlag();
assertTrue(cpu.getIrqDisableFlag());
bus.loadProgram(0x58);
cpu.step();
assertFalse(cpu.getIrqDisableFlag());
}
/* CLV - Clear Overflow Flag - $b8 */
@Test
public void test_CLV() throws MemoryAccessException {
cpu.setOverflowFlag();
assertTrue(cpu.getOverflowFlag());
bus.loadProgram(0xb8);
cpu.step();
assertFalse(cpu.getOverflowFlag());
}
/* DEX - Decrement the X register - $ca */
@Test
public void test_DEX() throws MemoryAccessException {
bus.loadProgram(0xca);
cpu.setXRegister(0x02);
cpu.step();
assertEquals(0x01, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_DEX_SetsZeroFlagWhenZero() throws MemoryAccessException {
bus.loadProgram(0xca);
cpu.setXRegister(0x01);
cpu.step();
assertEquals(0x00, cpu.getXRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_DEX_SetsNegativeFlagWhen() throws MemoryAccessException {
bus.loadProgram(0xca);
cpu.step();
assertEquals(0xff, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
/* DEY - Decrement the Y register - $88 */
@Test
public void test_DEY() throws MemoryAccessException {
bus.loadProgram(0x88);
cpu.setYRegister(0x02);
cpu.step();
assertEquals(0x01, cpu.getYRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_DEY_SetsZeroFlagWhenZero() throws MemoryAccessException {
bus.loadProgram(0x88);
cpu.setYRegister(0x01);
cpu.step();
assertEquals(0x00, cpu.getYRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_DEY_SetsNegativeFlagWhen() throws MemoryAccessException {
bus.loadProgram(0x88);
cpu.step();
assertEquals(0xff, cpu.getYRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
/* INX - Increment the X register - $e8 */
@Test
public void test_INX() throws MemoryAccessException {
bus.loadProgram(0xe8);
cpu.step();
assertEquals(0x01, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_INX_SetsNegativeFlagWhenNegative() throws MemoryAccessException {
bus.loadProgram(0xe8);
cpu.setXRegister(0x7f);
cpu.step();
assertEquals(0x80, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
@Test
public void test_INX_SetsZeroFlagWhenZero() throws MemoryAccessException {
bus.loadProgram(0xe8);
cpu.setXRegister(0xff);
cpu.step();
assertEquals(0x00, cpu.getXRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
/* INY - Increment the Y register - $c8 */
@Test
public void test_INY() throws MemoryAccessException {
bus.loadProgram(0xc8);
cpu.step();
assertEquals(0x01, cpu.getYRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_INY_SetsNegativeFlagWhenNegative() throws MemoryAccessException {
bus.loadProgram(0xc8);
cpu.setYRegister(0x7f);
cpu.step();
assertEquals(0x80, cpu.getYRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
@Test
public void test_INY_SetsZeroFlagWhenZero() throws MemoryAccessException {
bus.loadProgram(0xc8);
cpu.setYRegister(0xff);
cpu.step();
assertEquals(0x00, cpu.getYRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
/* NOP - No Operation - $ea */
@Test
public void test_NOP() throws MemoryAccessException {
bus.loadProgram(0xea);
cpu.step();
// Should just not change anything except PC
assertEquals(0, cpu.getAccumulator());
assertEquals(0, cpu.getXRegister());
assertEquals(0, cpu.getYRegister());
assertEquals(0x201, cpu.getProgramCounter());
assertEquals(0xff, cpu.getStackPointer());
assertEquals(0x20, cpu.getProcessorStatus());
}
/* PHA - Push Accumulator - $48 */
@Test
public void test_PHA() throws MemoryAccessException {
bus.loadProgram(0x48);
cpu.setAccumulator(0x3a);
cpu.step();
assertEquals(0xfe, cpu.getStackPointer());
assertEquals(0x3a, cpu.stackPeek());
}
/* PHP - Push Processor Status - $08 */
@Test
public void test_PHP() throws MemoryAccessException {
bus.loadProgram(0x08);
cpu.setProcessorStatus(0x27);
cpu.step();
assertEquals(0xfe, cpu.getStackPointer());
// PHP should have set the BREAK flag _on the stack_ (but not in the CPU)
assertEquals(0x37, cpu.stackPeek());
assertEquals(0x27, cpu.getProcessorStatus());
}
/* PLA - Pul Accumulator - $68 */
@Test
public void test_PLA() throws MemoryAccessException {
cpu.stackPush(0x32);
bus.loadProgram(0x68);
cpu.step();
assertEquals(0x32, cpu.getAccumulator());
assertFalse(cpu.getNegativeFlag());
assertFalse(cpu.getZeroFlag());
}
@Test
public void test_PLA_SetsZeroIfAccumulatorIsZero() throws MemoryAccessException {
cpu.stackPush(0x00);
bus.loadProgram(0x68);
cpu.step();
assertEquals(0x00, cpu.getAccumulator());
assertFalse(cpu.getNegativeFlag());
assertTrue(cpu.getZeroFlag());
}
@Test
public void test_PLA_SetsNegativeIfAccumulatorIsNegative() throws MemoryAccessException {
cpu.stackPush(0xff);
bus.loadProgram(0x68);
cpu.step();
assertEquals(0xff, cpu.getAccumulator());
assertTrue(cpu.getNegativeFlag());
assertFalse(cpu.getZeroFlag());
}
/* PLP - Pull Processor Status - $28 */
@Test
public void test_PLP() throws MemoryAccessException {
cpu.stackPush(0x2f);
bus.loadProgram(0x28);
cpu.step();
assertEquals(0x2f, cpu.getProcessorStatus());
}
/* RTI - Return from Interrupt - $40 */
@Test
public void test_RTI() throws MemoryAccessException {
cpu.stackPush(0x0f); // PC hi
cpu.stackPush(0x11); // PC lo
cpu.stackPush(0x29); // status
bus.loadProgram(0x40);
cpu.step();
assertEquals(0x0f11, cpu.getProgramCounter());
assertEquals(0x29, cpu.getProcessorStatus());
}
/* RTS - Return from Subroutine - $60 */
@Test
public void test_RTS() throws MemoryAccessException {
cpu.stackPush(0x0f); // PC hi
cpu.stackPush(0x11); // PC lo
bus.loadProgram(0x60);
cpu.step();
assertEquals(0x0f12, cpu.getProgramCounter());
assertEquals(0x20, cpu.getProcessorStatus());
}
/* SEC - Set Carry Flag - $38 */
@Test
public void test_SEC() throws MemoryAccessException {
bus.loadProgram(0x38);
cpu.step();
assertTrue(cpu.getCarryFlag());
}
/* SED - Set Decimal Mode Flag - $f8 */
@Test
public void test_SED() throws MemoryAccessException {
bus.loadProgram(0xf8);
cpu.step();
assertTrue(cpu.getDecimalModeFlag());
}
/* SEI - Set Interrupt Disable Flag - $78 */
@Test
public void test_SEI() throws MemoryAccessException {
bus.loadProgram(0x78);
cpu.step();
assertTrue(cpu.getIrqDisableFlag());
}
/* TAX - Transfer Accumulator to X Register - $aa */
@Test
public void test_TAX() throws MemoryAccessException {
cpu.setAccumulator(0x32);
bus.loadProgram(0xaa);
cpu.step();
assertEquals(0x32, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TAX_SetsZeroFlagIfXIsZero() throws MemoryAccessException {
cpu.setAccumulator(0x00);
bus.loadProgram(0xaa);
cpu.step();
assertEquals(0x00, cpu.getXRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TAX_SetsNegativeFlagIfXIsNegative() throws MemoryAccessException {
cpu.setAccumulator(0xff);
bus.loadProgram(0xaa);
cpu.step();
assertEquals(0xff, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
/* TAY - Transfer Accumulator to Y Register - $a8 */
@Test
public void test_TAY() throws MemoryAccessException {
cpu.setAccumulator(0x32);
bus.loadProgram(0xa8);
cpu.step();
assertEquals(0x32, cpu.getYRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TAY_SetsZeroFlagIfYIsZero() throws MemoryAccessException {
cpu.setAccumulator(0x00);
bus.loadProgram(0xa8);
cpu.step();
assertEquals(0x00, cpu.getYRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TAY_SetsNegativeFlagIfYIsNegative() throws MemoryAccessException {
cpu.setAccumulator(0xff);
bus.loadProgram(0xa8);
cpu.step();
assertEquals(0xff, cpu.getYRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
/* TSX - Transfer Stack Pointer to X Register - $ba */
@Test
public void test_TSX() throws MemoryAccessException {
cpu.setStackPointer(0x32);
bus.loadProgram(0xba);
cpu.step();
assertEquals(0x32, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TSX_SetsZeroFlagIfXIsZero() throws MemoryAccessException {
cpu.setStackPointer(0x00);
bus.loadProgram(0xba);
cpu.step();
assertEquals(0x00, cpu.getXRegister());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TSX_SetsNegativeFlagIfXIsNegative() throws MemoryAccessException {
cpu.setStackPointer(0xff);
bus.loadProgram(0xba);
cpu.step();
assertEquals(0xff, cpu.getXRegister());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
/* TXA - Transfer X Register to Accumulator - $8a */
@Test
public void test_TXA() throws MemoryAccessException {
cpu.setXRegister(0x32);
bus.loadProgram(0x8a);
cpu.step();
assertEquals(0x32, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TXA_SetsZeroFlagIfAccumulatorIsZero() throws MemoryAccessException {
cpu.setXRegister(0x00);
bus.loadProgram(0x8a);
cpu.step();
assertEquals(0x00, cpu.getAccumulator());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TXA_SetsNegativeFlagIfAccumulatorIsNegative() throws MemoryAccessException {
cpu.setXRegister(0xff);
bus.loadProgram(0x8a);
cpu.step();
assertEquals(0xff, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
/* TXS - Transfer X Register to Stack Pointer - $9a */
@Test
public void test_TXS() throws MemoryAccessException {
cpu.setXRegister(0x32);
bus.loadProgram(0x9a);
cpu.step();
assertEquals(0x32, cpu.getStackPointer());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TXS_DoesNotAffectProcessorStatus() throws MemoryAccessException {
cpu.setXRegister(0x00);
bus.loadProgram(0x9a);
cpu.step();
assertEquals(0x00, cpu.getStackPointer());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
cpu.setXRegister(0x80);
bus.loadProgram(0x9a);
cpu.step();
assertEquals(0x80, cpu.getStackPointer());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
/* TYA - Transfer Y Register to Accumulator - $98 */
@Test
public void test_TYA() throws MemoryAccessException {
cpu.setYRegister(0x32);
bus.loadProgram(0x98);
cpu.step();
assertEquals(0x32, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TYA_SetsZeroFlagIfAccumulatorIsZero() throws MemoryAccessException {
cpu.setYRegister(0x00);
bus.loadProgram(0x98);
cpu.step();
assertEquals(0x00, cpu.getAccumulator());
assertTrue(cpu.getZeroFlag());
assertFalse(cpu.getNegativeFlag());
}
@Test
public void test_TYA_SetsNegativeFlagIfAccumulatorIsNegative() throws MemoryAccessException {
cpu.setYRegister(0xff);
bus.loadProgram(0x98);
cpu.step();
assertEquals(0xff, cpu.getAccumulator());
assertFalse(cpu.getZeroFlag());
assertTrue(cpu.getNegativeFlag());
}
}