More work on CPU

gb/cpu_test.go

@@ -0,0 +1,122 @@
+package gb
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func createCPU(data []byte) *CPU {
+	cart := Cartridge{Filename: "test"}
+	cart.Data = data
+	cpu := NewCPU(NewBus(&cart))
+	cpu.Regs.PC = 0
+
+	return cpu
+}
+
+func TestSetFlag(t *testing.T) {
+	cartridge, _ := InsertCartridge("../roms/dmg-acid2.gb")
+	bus := NewBus(cartridge)
+	cpu := NewCPU(bus)
+
+	cpu.SetFlag(C)
+
+	assert.True(t, cpu.IsFlagSet(C))
+}
+
+func TestClearFlag(t *testing.T) {
+	cartridge, _ := InsertCartridge("../roms/dmg-acid2.gb")
+	bus := NewBus(cartridge)
+	cpu := NewCPU(bus)
+
+	cpu.SetFlag(C)
+	assert.True(t, cpu.IsFlagSet(C))
+
+	cpu.ClearFlag(C)
+	assert.False(t, cpu.IsFlagSet(C))
+}
+
+func TestToggleFlag(t *testing.T) {
+	cartridge, _ := InsertCartridge("../roms/dmg-acid2.gb")
+	bus := NewBus(cartridge)
+	cpu := NewCPU(bus)
+
+	cpu.ToggleFlag(C)
+	assert.True(t, cpu.IsFlagSet(C))
+
+	cpu.ToggleFlag(C)
+	assert.False(t, cpu.IsFlagSet(C))
+}
+
+func TestInstruction00(t *testing.T) {
+	cpu := createCPU([]byte{0x00, 0x00, 0x00})
+
+	cpu.Step()
+
+	assert.Equal(t, cpu.Regs.PC, uint16(0x01))
+}
+
+func TestInstruction3C(t *testing.T) {
+	// Should increment A register
+	cpu := createCPU([]byte{0x3C, 0x00, 0x00})
+
+	assert.Equal(t, cpu.Regs.A, byte(0x0))
+	cpu.Step()
+	assert.Equal(t, cpu.Regs.A, byte(0x01))
+
+	// Should clear Zero Flag
+	cpu = createCPU([]byte{0x3C, 0x00, 0x00})
+
+	cpu.SetFlag(Z)
+	cpu.Step()
+	assert.False(t, cpu.IsFlagSet(Z))
+
+	// Should set Zero Flag
+	cpu = createCPU([]byte{0x3C, 0x00, 0x00})
+	cpu.Regs.A = 0xFF
+
+	assert.False(t, cpu.IsFlagSet(Z))
+	cpu.Step()
+	assert.True(t, cpu.IsFlagSet(Z))
+
+	// Should clear Subtract Flag
+	cpu = createCPU([]byte{0x3C, 0x00, 0x00})
+
+	cpu.SetFlag(N)
+	cpu.Step()
+	assert.False(t, cpu.IsFlagSet(N))
+
+	// Should set Half Carry Flag if we overflow from bit 3
+	cpu = createCPU([]byte{0x3C, 0x00, 0x00})
+	cpu.Regs.A = 0x0F
+
+	assert.False(t, cpu.IsFlagSet(H))
+	cpu.Step()
+	assert.True(t, cpu.IsFlagSet(H))
+
+	// Should clear Half Carry Flag if we don't overflow from bit 3
+	cpu = createCPU([]byte{0x3C, 0x00, 0x00})
+
+	cpu.SetFlag(H)
+	cpu.Step()
+	assert.False(t, cpu.IsFlagSet(H))
+}
+
+func TestInstructionC3(t *testing.T) {
+	cpu := createCPU([]byte{0xC3, 0x50, 0x01})
+
+	cpu.Step()
+
+	assert.Equal(t, cpu.Regs.PC, uint16(0x150))
+}
+
+func TestInstructionE9(t *testing.T) {
+	cpu := createCPU([]byte{0xE9, 0x00, 0x00})
+	cpu.Regs.H = 0x12
+	cpu.Regs.L = 0x34
+
+	cpu.Step()
+
+	assert.Equal(t, cpu.Regs.PC, uint16(0x1234))
+}