Assemble kernel on client

emu.js

@@ -11,6 +11,7 @@ const RXBUF_SIZE = 32;
 const PERIPHS_SIZE = 81;
 
 const POLL_INTERVAL_MS = 20;
+const DOT_INTERVAL_MS = 120;
 
 const COLS = 80;
 const TAB_WIDTH = 8;
@@ -50,8 +51,14 @@ class Emulator {
 		document.addEventListener('keydown', (e) => this.handle_keydown(e));
 		window.addEventListener('resize', () => this.handle_resize());
 
-		this.worker = new Worker('boot.js');
+		this.print("Assembling kernel ");
+		const dots = setInterval(() => this.print("."), DOT_INTERVAL_MS);
+		this.worker = new Worker('boot.js', { type: 'module' });
 		this.worker.postMessage(this.mem);
+		this.worker.onmessage = (e) => {
+			clearInterval(dots);
+			this.print(" done\n");
+		};
 
 		fetch('prelude.f')
 			.then(res => res.text())