diff --git a/src/main.ha b/src/main.ha
index 53af99d..5eace44 100644
--- a/src/main.ha
+++ b/src/main.ha
@@ -124,7 +124,14 @@ export fn main() void = {
 
 			if(state.screen_vector != 0){
 				// fmt::println("Executing screen vector")!;
-				uxn::uxn_eval(state.screen_vector, state)!;
+				match (uxn::uxn_eval(state.screen_vector, state)) {
+					case done =>
+						yield;
+					case uxn::quit =>
+						run = false;
+					case let err: uxn::error =>
+						fmt::fatalf("Error evaluating: {}", uxn::strerror(err));
+				};
 			};
 		};
 		if(state.screen_size_changed){
@@ -223,17 +230,44 @@ export fn main() void = {
 					const x = ev.motion.x / scale: f32;
 					const y = ev.motion.y / scale: f32;
 					uxn::set_mouse_motion(x: u16,y: u16,state);
-					if(state.mouse_vector != 0 ) uxn::uxn_eval(state.mouse_vector,state)!;
+					if(state.mouse_vector != 0 ){				
+						match (uxn::uxn_eval(state.mouse_vector, state)) {
+							case done =>
+								yield;
+							case uxn::quit =>
+								run = false;
+							case let err: uxn::error =>
+								fmt::fatalf("Error evaluating: {}", uxn::strerror(err));
+						};
+					};
 				case sdl3::EventType::MOUSE_BUTTON_DOWN =>
 					// fmt::printfln("Mouse Down: 0x{:x}", ev.button.button: u8 )!;
 					const b = 1 << (ev.button.button: u8 - 1);
 					uxn::set_mouse_down(b,state);
-					if(state.mouse_vector != 0 ) uxn::uxn_eval(state.mouse_vector,state)!;
+					if(state.mouse_vector != 0 ){				
+						match (uxn::uxn_eval(state.mouse_vector, state)) {
+							case done =>
+								yield;
+							case uxn::quit =>
+								run = false;
+							case let err: uxn::error =>
+								fmt::fatalf("Error evaluating: {}", uxn::strerror(err));
+						};
+					};
 				case sdl3::EventType::MOUSE_BUTTON_UP =>
 					// fmt::printfln("Mouse Up: 0x{:x}", ev.button.button: u8 )!;
 					const b = 1 << (ev.button.button: u8 - 1);
 					uxn::set_mouse_up(b,state);
-					if(state.mouse_vector != 0 ) uxn::uxn_eval(state.mouse_vector,state)!;
+					if(state.mouse_vector != 0 ){				
+						match (uxn::uxn_eval(state.mouse_vector, state)) {
+							case done =>
+								yield;
+							case uxn::quit =>
+								run = false;
+							case let err: uxn::error =>
+								fmt::fatalf("Error evaluating: {}", uxn::strerror(err));
+						};
+					};
 				case sdl3::EventType::MOUSE_WHEEL =>
 					fmt::printfln("Mouse Wheel!")!;
 				case sdl3::EventType::WINDOW_EXPOSED =>
diff --git a/uxn/uxn.ha b/uxn/uxn.ha
index 1a76e93..965a559 100644
--- a/uxn/uxn.ha
+++ b/uxn/uxn.ha
@@ -79,9 +79,15 @@ export fn set_window_size(w: u16, h: u16, state: *uxn) void = {
 };
 
 fn emu_dei(port: u8, state: *uxn) u8 = {
-	let val = state.dev[port];
+	switch(port) {
+		case 0x04 =>
+			return state.ptr[0];
+		case 0x05 =>
+			return state.ptr[1];
+		case =>
+			return state.dev[port];
 	// fmt::printfln("Read {:x} from port {:x}", val, port)!;
-	return val;
+	};
 };
 
 
@@ -89,6 +95,10 @@ fn emu_deo(port: u8, value: u8, state: *uxn) void = {
 	// fmt::printfln("Writing {:x} to port {:x}", value, port)!;
 	state.dev[port] = value;
 	switch(port) {
+	case 0x04 =>
+		state.ptr[0] = value;
+	case 0x05 =>
+		state.ptr[1] = value;
 	case 0x11 =>
 		let high = state.dev[0x10];
 		let low = value;
@@ -375,6 +385,7 @@ export fn get_color(x: u16, y: u16, state: *uxn) u16 = {
 
 export type evalerror = !void;
 export type unhandled = !u8;
+export type quit = void;
 
 export type error = !(evalerror | unhandled);
 
@@ -606,13 +617,14 @@ fn pop_or_get(inst: normal_op, off: u8, state: *uxn) (u8 | u16) = {
 			yield get_stack_val(inst.ret,inst.short, off,state);
 	};
 };
-export fn uxn_eval(new_pc: u16, state: *uxn) (done | error ) = {
+export fn uxn_eval(new_pc: u16, state: *uxn) (done | quit | error ) = {
 	// let a: u16 = 0, b: u16 = 0, c: u16 = 0, x: [2]u16 = [0...], y: [2]u16 = [0...], z: [2]u16 = [0...];
 	state.pc = new_pc;
 	state.running = true;
 	for(state.running){
 		uxn_step(state)?;
 	};
+	if(state.dev[0x0f] != 0) return quit;
 	return done;
 };
 
@@ -1007,7 +1019,7 @@ export fn console_input(c: u8, ctype: u8, state: *uxn) (done | error) = {
 
 
 // Converts an error into a user-friendly string
-fn strerror(err: error) str = {
+export fn strerror(err: error) str = {
 	match (err) {
 	case evalerror =>
 		return "Reached unexpected part of eval code";