@@ -116,7 +116,7 @@ timeout:

 /* clang-format on */

 int

-uxn_boot(Uxn *u, Uint8 *ram)

+uxn_boot(Uxn *u, Uint8 *ram, Dei *dei, Deo *deo)

 {

 	Uint32 i;

 	char *cptr = (char *)u;

@@ -49,9 +49,14 @@ typedef struct Uxn {

 	Uint8 *ram;

 	Stack wst, rst;

 	Device dev[16];

+	Uint8 (*dei)(struct Uxn *u, Uint8 addr);

+	void (*deo)(struct Uxn *u, Uint8 addr, Uint8 value);

 } Uxn;

-int uxn_boot(Uxn *u, Uint8 *ram);

+typedef Uint8 Dei(Uxn *u, Uint8 addr);

+typedef void Deo(Uxn *u, Uint8 addr, Uint8 value);

+

+int uxn_boot(Uxn *u, Uint8 *ram, Dei *dei, Deo *deo);

 int uxn_eval(Uxn *u, Uint16 pc);

 int uxn_interrupt(void);

 int uxn_halt(Uxn *u, Uint8 error, Uint16 addr);

@@ -24,6 +24,17 @@ error(char *msg, const char *err)

 	return 0;

 }

+static Uint8

+emu_dei(Uxn *u, Uint8 addr)

+{

+	return 0;

+}

+

+static void

+emu_deo(Uxn *u, Uint8 addr, Uint8 v)

+{

+}

+

 void

 system_deo_special(Device *d, Uint8 port)

 {

@@ -83,7 +94,7 @@ uxn_interrupt(void)

 static int

 start(Uxn *u)

 {

-	if(!uxn_boot(u, (Uint8 *)calloc(0x10000, sizeof(Uint8))))

+	if(!uxn_boot(u, (Uint8 *)calloc(0x10000, sizeof(Uint8)), emu_dei, emu_deo))

 		return error("Boot", "Failed");

 	/* system   */ uxn_port(u, 0x0, system_dei, system_deo);

 	/* console  */ uxn_port(u, 0x1, nil_dei, console_deo);

@@ -176,6 +176,17 @@ init(void)

 #pragma mark - Devices

+static Uint8

+emu_dei(Uxn *u, Uint8 addr)

+{

+	return 0;

+}

+

+static void

+emu_deo(Uxn *u, Uint8 addr, Uint8 v)

+{

+}

+

 void

 system_deo_special(Device *d, Uint8 port)

 {

@@ -253,7 +264,7 @@ static int

 start(Uxn *u, char *rom)

 {

 	free(u->ram);

-	if(!uxn_boot(u, calloc(0x10000, 1)))

+	if(!uxn_boot(u, calloc(0x10000, 1), emu_dei, emu_deo))

 		return error("Boot", "Failed to start uxn.");

 	if(!load(u, rom))

 		return error("Boot", "Failed to load rom.");