very basic emulator structure

chip8/chip8.go

@@ -1 +1,35 @@
 package chip8
+
+type Emulator struct {
+	V      [16]uint8   // general registers
+	I      uint16      // address register
+	SP     uint16      // stack pointer
+	PC     uint16      // program counter
+	Memory [4096]uint8 // 4KB of system RAM
+	Stack  []uint8     // 32 bytes of stack. starting at 0x0EA0
+	Screen []uint8     // 256 bytes of display buffer. starting at 0x0F00
+	Timer  struct {
+		Delay uint8 // delay timer
+		Sound uint8 // sound timer
+	}
+	ROM []uint8
+}
+
+func NewEmulator() *Emulator {
+	emulator := new(Emulator)
+	emulator.Reset()
+	return emulator
+}
+
+func (emulator *Emulator) Reset() {
+	emulator.V = [16]uint8{}
+	emulator.I = 0x00
+	emulator.SP = 0x00
+	emulator.PC = 0x0200
+	emulator.Memory = [4096]uint8{}
+	emulator.Stack = emulator.Memory[0x0EA0:]
+	emulator.Screen = emulator.Memory[0x0F00:]
+	emulator.Timer.Delay = 0
+	emulator.Timer.Sound = 0
+	copy(emulator.Memory[0x0200:], emulator.ROM)
+}

chip8/chip8_test.go

@@ -1 +1,19 @@
 package chip8_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tangzero/chip8-emulator/chip8"
+)
+
+func TestEmulator_Reset(t *testing.T) {
+	emulator := chip8.NewEmulator()
+	emulator.V[0x03] = 0xFF
+	emulator.V[0x0F] = 0xBB
+
+	emulator.Reset()
+
+	assert.Equal(t, uint8(0x00), emulator.V[0x03])
+	assert.Equal(t, uint8(0x00), emulator.V[0x0F])
+}

go.mod

@@ -1,3 +1,10 @@
 module github.com/tangzero/chip8-emulator
 
 go 1.17
+
+require (
+	github.com/davecgh/go-spew v1.1.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.7.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
+)