add debugging setup

Makefile

@@ -14,6 +14,10 @@ build: clean
 run: build
 	./Sapphire.app/Contents/MacOS/sapphire
 
+.PHONY: run-debug
+run-debug:
+	go run -tags debug ./debugger
+
 .PHONY: package
 package: build
 	zip -r build/sapphire.zip Sapphire.app

debugger/debugger.go

@@ -0,0 +1,22 @@
+//go:build debug
+
+package main
+
+import (
+	"os"
+
+	"github.com/dbut2/sapphire/gba"
+)
+
+func main() {
+	gameData, err := os.ReadFile("sapphire.gba")
+	if err != nil {
+		panic(err.Error())
+	}
+	e := gba.NewEmu(gameData)
+
+	e.Hooks.RegisterHook(gba.PreStepCPUEmuHook, func(emulator *gba.Emulator) {
+		// Do something before CPU step
+	})
+	e.Boot()
+}

debugger/hooks/hooks.go

@@ -0,0 +1,19 @@
+package hooks
+
+type HookService[T ~int, V any] map[T]func(V)
+
+func (h *HookService[T, V]) RegisterHook(hook T, f func(V)) {
+	if *h == nil {
+		*h = make(HookService[T, V])
+	}
+	(*h)[hook] = f
+}
+
+func (h *HookService[T, V]) Hook(hook T, v V) {
+	if *h == nil {
+		*h = make(HookService[T, V])
+	}
+	if f, ok := (*h)[hook]; ok {
+		f(v)
+	}
+}

gba/emu.go

@@ -1,15 +1,18 @@
 package gba
 
 import (
+	"image"
 	"time"
 )
 
-type Emulator struct {
-	*Motherboard
-}
-
 func NewEmu(gamepak []byte) *Emulator {
-	return &Emulator{Motherboard: NewMotherboard(gamepak)}
+	motherboard := NewMotherboard(gamepak)
+
+	img := image.NewRGBA(image.Rect(0, 0, 240, 160))
+	motherboard.LCD.SetImage(img)
+	motherboard.LCD.SetDraw(func() {})
+
+	return &Emulator{Motherboard: motherboard}
 }
 
 func (e *Emulator) Boot() {
@@ -74,7 +77,7 @@ func (e *Emulator) step() {
 	SetIORegister(e.Memory, DISPSTAT, dispstat)
 
 	preCount := e.CPU.cycles
-	e.CPU.Step()
+	e.stepCPU()
 	postCount := e.CPU.cycles
 
 	e.Timer.Tick(postCount - preCount)

gba/emu_debug.go

@@ -0,0 +1,26 @@
+//go:build debug
+
+package gba
+
+import (
+	"github.com/dbut2/sapphire/debugger/hooks"
+)
+
+type Emulator struct {
+	*Motherboard
+
+	Hooks hooks.HookService[EmuHook, *Emulator]
+}
+
+type EmuHook int
+
+const (
+	PreStepCPUEmuHook EmuHook = iota
+	PostStepCPUEmuHook
+)
+
+func (e *Emulator) stepCPU() {
+	e.Hooks.Hook(PreStepCPUEmuHook, e)
+	e.CPU.Step()
+	e.Hooks.Hook(PostStepCPUEmuHook, e)
+}

gba/emu_prod.go

@@ -0,0 +1,11 @@
+//go:build !debug
+
+package gba
+
+type Emulator struct {
+	*Motherboard
+}
+
+func (e *Emulator) stepCPU() {
+	e.CPU.Step()
+}