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b5a470d3ba
When describing the CPU's reset pin, the W65C02S data sheet says: > All Registers are initialized by software except the Decimal and Interrupt > disable mode select bits of the Processor Status Register (P) are initialized > by hardware. It then has a diagram of the power-on state of the processor status register: > 7 6 5 4 3 2 1 0 > * * 1 1 0 1 * * > N V - B D I Z C > > * = software initialized Confusingly the text indicates that only the D and I flags are initialised by hardware, while the diagram indicates that the B flag is initialised too. Meanwhile, https://www.nesdev.org/wiki/CPU_power_up_state says that the power-on state of the NES CPU is $34 (exactly matching the diagram above) but https://www.nesdev.org/wiki/Status_flags#The_B_flag says that the B flag does not physically exist within P register, it's only relevant in the copy of P that gets pushed to the stack by BRK (set), PHP (set), or an interrupt signal (cleared). As a result, the most sensible power-on state for the processor status register is with the "interrupt disable" flag set and everything else cleared.
310 lines
10 KiB
Java
310 lines
10 KiB
Java
package com.loomcom.symon;
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import com.loomcom.symon.devices.Memory;
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import com.loomcom.symon.exceptions.*;
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import junit.framework.*;
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public class CpuAccumulatorModeTest extends TestCase {
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protected Cpu cpu;
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protected Bus bus;
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protected Memory mem;
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public void setUp() throws MemoryRangeException, MemoryAccessException {
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this.cpu = new Cpu();
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this.bus = new Bus(0x0000, 0xffff);
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this.mem = new Memory(0x0000, 0xffff);
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bus.addCpu(cpu);
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bus.addDevice(mem);
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// Load the reset vector.
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bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
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bus.write(0xfffd, (Bus.DEFAULT_LOAD_ADDRESS & 0xff00) >>> 8);
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cpu.reset();
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// Assert initial state
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assertEquals(0, cpu.getAccumulator());
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assertEquals(0, cpu.getXRegister());
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assertEquals(0, cpu.getYRegister());
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assertEquals(0x200, cpu.getProgramCounter());
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assertEquals(0xff, cpu.getStackPointer());
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assertEquals(0x24, cpu.getProcessorStatus());
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}
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/*
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* The following opcodes are tested for correctness in this file:
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*
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* ASL - $0a
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* ROL - $2a
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* LSR - $4a
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* ROR - $6a
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*/
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/* ASL - Arithmetic Shift Left - $0a */
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public void test_ASL() throws MemoryAccessException {
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bus.loadProgram(0xa9, 0x00, // LDA #$00
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0x0a, // ASL A
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0xa9, 0x01, // LDA #$01
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0x0a, // ASL A
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0xa9, 0x02, // LDA #$02
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0x0a, // ASL A
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0xa9, 0x44, // LDA #$44
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0x0a, // ASL A
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0xa9, 0x80, // LDA #$80
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0x0a); // ASL A
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cpu.step(2);
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assertEquals(0x00, cpu.getAccumulator());
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assertTrue(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x02, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x04, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x88, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertTrue(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x00, cpu.getAccumulator());
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assertTrue(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertTrue(cpu.getCarryFlag());
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}
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/* ROL - Rotate Left - $2a */
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public void test_ROL() throws MemoryAccessException {
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bus.loadProgram(0xa9, 0x00, // LDA #$00
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0x2a, // ROL A (m=%00000000, c=0)
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0xa9, 0x01, // LDA #$01
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0x2a, // ROL A (m=%00000010, c=0)
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0x38, // SEC (m=%00000010, c=1)
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0x2a, // ROL A (m=%00000101, c=0)
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0x2a, // ROL A (m=%00001010, c=0)
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0x2a, // ROL A (m=%00010100, c=0)
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0x2a, // ROL A (m=%00101000, c=0)
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0x2a, // ROL A (m=%01010000, c=0)
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0x2a, // ROL A (m=%10100000, c=0)
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0x2a, // ROL A (m=%01000000, c=1)
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0x2a); // ROL A (m=%10000001, c=0)
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cpu.step(2);
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assertEquals(0x00, cpu.getAccumulator());
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assertTrue(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x02, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x05, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x0a, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x14, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x28, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x50, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0xa0, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertTrue(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x40, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertTrue(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x81, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertTrue(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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}
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/* LSR - Logical Shift Right - $4a */
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public void test_LSR() throws MemoryAccessException {
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bus.loadProgram(0xa9, 0x00, // LDA #$00
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0x4a, // LSR A
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0xa9, 0x01, // LDA #$01
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0x4a, // LSR A
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0xa9, 0x02, // LDA #$02
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0x4a, // LSR A
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0xa9, 0x44, // LDA #$44
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0x4a, // LSR A
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0xa9, 0x80, // LDA #$80
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0x4a, // LSR A
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0x38, // SEC
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0xa9, 0x02, // LDA #$02
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0x4a); // LSR $05
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cpu.step(2);
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assertEquals(0x00, cpu.getAccumulator());
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assertTrue(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x00, cpu.getAccumulator());
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assertTrue(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertTrue(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x01, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x22, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x40, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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// Setting Carry should not affect the result.
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cpu.step(3);
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assertEquals(0x01, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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}
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/* ROR - Rotate Right - $6a */
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public void test_ROR() throws MemoryAccessException {
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bus.loadProgram(0xa9, 0x00, // LDA #$00
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0x6a, // ROR A (m=%00000000, c=0)
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0xa9, 0x10, // LDA #$10
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0x6a, // ROR A (m=%00001000, c=0)
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0x6a, // ROR A (m=%00000100, c=0)
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0x6a, // ROR A (m=%00000010, c=0)
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0x6a, // ROR A (m=%00000001, c=0)
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0x6a, // ROR A (m=%00000000, c=1)
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0x6a, // ROR A (m=%10000000, c=0)
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0x6a, // ROR A (m=%01000000, c=0)
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0x6a, // ROR A (m=%00100000, c=0)
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0x6a); // ROR A (m=%00010000, c=0)
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cpu.step(2);
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assertEquals(0x00, cpu.getAccumulator());
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assertTrue(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step(2);
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assertEquals(0x08, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x04, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x02, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x01, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x00, cpu.getAccumulator());
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assertTrue(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertTrue(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x80, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertTrue(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x40, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x20, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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cpu.step();
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assertEquals(0x10, cpu.getAccumulator());
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assertFalse(cpu.getZeroFlag());
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assertFalse(cpu.getNegativeFlag());
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assertFalse(cpu.getCarryFlag());
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}
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}
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