Use atomic wait/notify on RXTAIL in KEY

emu.js

@@ -27,6 +27,7 @@ class Emulator {
 		this.mem_u8 = new Uint8Array(this.mem.buffer);
 		for (let i = 0; i < PERIPHS_SIZE; ++i)
 			this.mem_u8[i] = 0;
+		this.mem_i32 = new Int32Array(this.mem.buffer);
 
 		this.decoder = new TextDecoder('utf-8');
 		this.encoder = new TextEncoder('utf-8');
@@ -103,6 +104,7 @@ class Emulator {
 			tail = this.fifo_next(tail);
 		} while (this.fifo_next(tail) != head && this.rx_queue.length != 0);
 		Atomics.store(this.mem_u8, RXTAIL, tail);
+		Atomics.notify(this.mem_i32, RXTAIL / 4);
 	}
 
 	print(str) {