At long last, implemented BRK. Lots more unit tests for stack processing, as well.

2008-12-23 02:21:27 -08:00
1 parent 46a5943736
commit 473b47e832
@@ -0,0 +1,130 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+import junit.framework.*;
+
+public class CpuImpliedModeTest extends TestCase {
+
+	protected Cpu cpu;
+	protected Bus bus;
+	protected Memory mem;
+
+	public void setUp() throws MemoryRangeException {
+		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();
+	}
+
+	/*
+	 * 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 */
+
+	public void test_BRK() {
+		cpu.setCarryFlag();
+		cpu.setOverflowFlag();
+		assertEquals(0x20|Cpu.P_CARRY|Cpu.P_OVERFLOW,
+								 cpu.getProcessorStatus());
+		assertEquals(0xff, cpu.stackPeek());
+		assertFalse(cpu.getBreakFlag());
+		assertEquals(0x0200, cpu.getProgramCounter());
+		assertEquals(0xff, cpu.getStackPointer());
+
+		bus.loadProgram(0xea,
+										0xea,
+										0xea,
+										0x00);
+
+		cpu.step(3); // Three NOP instructions
+
+		assertEquals(0x203, cpu.getProgramCounter());
+
+		cpu.step(); // Triggers the BRK
+
+		// Was at PC = 0x204, which should now be on the stack
+		assertEquals(0x02, bus.read(0x1ff)); // PC high byte
+		assertEquals(0x04, bus.read(0x1fe)); // PC low byte
+		assertEquals(0x20|Cpu.P_CARRY|Cpu.P_OVERFLOW,
+								 bus.read(0x1fd));       // Processor Status
+
+		// Reset to original contents of PC
+		assertEquals(0x0200, cpu.getProgramCounter());
+		assertEquals(0xfc, cpu.getStackPointer());
+		assertEquals(0x20|Cpu.P_CARRY|Cpu.P_OVERFLOW|Cpu.P_BREAK,
+								 cpu.getProcessorStatus());
+		assertEquals(0x20|Cpu.P_CARRY|Cpu.P_OVERFLOW,
+								 cpu.stackPeek());
+	}
+
+	public void test_BRK_HonorsIrqDisableFlag() {
+		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());
+	}
+
+}