Handle prelude loading message in JS rather than Forth

README.md

@@ -99,6 +99,9 @@ unoccupied byte between the tail and the head.
 | Name     | Address | Size / B | Access       |
 |----------|---------|----------|--------------|
 | SYSREADY | 110h    | 4        | atomic write |
+| SYSINTER | 114h    | 4        | atomic read  |
 
 The `SYSREADY` register is used to indicate when the system has booted
-up and is ready for user input.
+up and is ready for user input.  `SYSINTER` is set (and notified on)
+once the emulator has enabled user input and the system is
+interactive.

emu.js

@@ -6,6 +6,7 @@ const RXHEAD = 0x108;
 const RXTAIL = 0x10c;
 
 const SYSREADY = 0x110;
+const SYSINTER = 0x114;
 
 const DOT_INTERVAL_MS = 120;
 const PERIPHS_SIZE = 0x200;
@@ -50,14 +51,18 @@ class Emulator {
 		document.addEventListener('keydown', (e) => this.handle_keydown(e));
 		window.addEventListener('resize', () => this.handle_resize());
 
+		this.forth = new Worker('boot.js', { type: 'module' });
+
 		this.print("Assembling kernel ");
-		const dots = setInterval(() => this.print("."), DOT_INTERVAL_MS);
+		this.dots = setInterval(() => this.print("."), DOT_INTERVAL_MS);
-		this.worker = new Worker('boot.js', { type: 'module' });
+		this.forth.postMessage({ type: "load", mem: this.mem });
-		this.worker.postMessage({ type: "load", mem: this.mem });
+		this.forth.onmessage = (e) => {
-		this.worker.onmessage = (e) => {
+			clearInterval(this.dots);
-			clearInterval(dots);
 			this.print(" done\n");
-			this.worker.postMessage({ type: "boot" });
+
+			this.print("Loading prelude ");
+			this.forth.postMessage({ type: "boot" });
+			this.dots = setInterval(() => this.print("."), DOT_INTERVAL_MS);
 		};
 
 		fetch('prelude.f')
@@ -84,9 +89,15 @@ class Emulator {
 		if (!this.input_enable) {
 			const sysready = Atomics.load(this.mem_u8, SYSREADY);
 			if (sysready != 0) {
+				clearInterval(this.dots);
+				this.print(" done\n");
+
+				Atomics.store(this.mem_u8, SYSINTER, 1);
+				Atomics.notify(this.mem_i32, SYSINTER / 4);
+
 				this.input_enable = true;
+				this.blink = true;
 				this.flush_output();
-				document.getElementById('cursor').classList.add('blinking');
 			}
 		}
 	}
@@ -180,12 +191,14 @@ class Emulator {
 		}
 
 		e.preventDefault();
+		this.blink = false;
 		this.flush_output();
 
 		document.getElementById('cursor').classList.remove('blinking');
 		if (this.idle_timer)
 			clearTimeout(this.idle_timer);
 		this.idle_timer = setTimeout(() => {
+			this.blink = true;
 			document.getElementById('cursor').classList.add('blinking');
 		}, CURSOR_IDLE_TIME_MS);
 	}
@@ -272,10 +285,12 @@ class Emulator {
 			return row.map((c, x) => {
 				const ec = this.html_escape(c);
 				if (this.input_enable
-					&& x == this.cursor.x && y == this.cursor.y)
+					&& x == this.cursor.x && y == this.cursor.y) {
-					return '<span id="cursor">' + ec + '</span>';
+					const cl = this.blink ? 'class="blinking"' : '';
-				else
+					return `<span id="cursor" ${cl}>` + ec + '</span>';
+				} else {
 					return ec;
+				}
 			}).join('').trimEnd();
 		}).join('\n');
 		this.output.innerHTML = html;

prelude.f

@@ -1,12 +1,5 @@
-76 EMIT 111 EMIT 97 EMIT 100 EMIT 105 EMIT 110 EMIT 103 EMIT 32 EMIT
-112 EMIT 114 EMIT 101 EMIT 108 EMIT 117 EMIT 100 EMIT 101 EMIT 32 EMIT
-
 : \ KEY 10 = 0BRANCH [ -20 , ] ; IMMEDIATE \ Now we have line comments :)
 
-\ We'll periodically sprinkle these in so that it's clear to the user
-\ that things are happening.
-46 EMIT
-
 \ Conditionals
 
 : IF
@@ -27,8 +20,6 @@
   SWAP !
 ; IMMEDIATE
 
-46 EMIT
-
 \ Loops
 
 : BEGIN HERE @ ; IMMEDIATE
@@ -43,8 +34,6 @@
   HERE @ - ,
 ; IMMEDIATE
 
-46 EMIT
-
 \ Recursive calls
 
 : RECURSE LATEST @ >CFA , ; IMMEDIATE
@@ -61,8 +50,6 @@
 
 ( ( Take that, C ) )
 
-46 EMIT
-
 \ Printing utilities
 
 : CR 10 EMIT ;
@@ -80,8 +67,6 @@
   + EMIT
 ;
 
-CHAR . EMIT
-
 : .
   \ Handle negatives
   DUP 0< IF CHAR - EMIT NEGATE THEN
@@ -110,8 +95,6 @@ CHAR . EMIT
   2DROP
 ;
 
-CHAR . EMIT
-
 : TYPE ( addr len -- )
   BEGIN
 	DUP 0= IF 2DROP EXIT THEN
@@ -120,8 +103,6 @@ CHAR . EMIT
   AGAIN
 ;
 
-CHAR . EMIT
-
 : C, HERE @ C! 1 HERE +! ;
 
 : ."
@@ -151,8 +132,6 @@ CHAR . EMIT
   THEN
 ; IMMEDIATE
 
-CHAR . EMIT
-
 \ Misc utilities
 
 : NIP SWAP DROP ;
@@ -171,8 +150,6 @@ CHAR . EMIT
 
 : [COMPILE] ' , ; IMMEDIATE
 
-CHAR . EMIT
-
 \ Constants, variables and values
 
 : CONSTANT
@@ -204,8 +181,6 @@ CHAR . EMIT
   THEN
 ; IMMEDIATE
 
-CHAR . EMIT
-
 \ Peripheral register addresses
 
 HEX
@@ -217,11 +192,10 @@ HEX
 108 CONSTANT RXHEAD
 10C CONSTANT RXTAIL
 110 CONSTANT SYSREADY
+114 CONSTANT SYSINTER
 
 DECIMAL
 
-46 EMIT
-
 \ A better word-not-found handler
 
 : ANY-RX? RXHEAD AC@ RXTAIL AC@ <> ;
@@ -244,8 +218,6 @@ DECIMAL
 
 ' WNF-HANDLER TO WNFHOOK
 
-CHAR . EMIT
-
 \ Version number
 
 0 CONSTANT VERSION-MAJOR
@@ -258,8 +230,6 @@ CHAR . EMIT
   CHAR . EMIT VERSION-PATCH .
 ;
 
-CHAR . EMIT
-
 \ Welcome banner
 
 : BANNER
@@ -277,8 +247,8 @@ CHAR . EMIT
   CR
 ;
 
-."  done" CR
+\ Set SYSREADY high and wait until interactive
-BANNER
-
-\ Set SYSREADY high to enable user input
 1 SYSREADY AC!
+SYSINTER WAIT DROP
+
+BANNER

wipforth.ws

@@ -635,6 +635,15 @@
     end
     call next
 
+.func wait
+.elem codewords wait WAIT_CODEWORD
+	call pop
+	i32.const 0
+	i64.const -1
+	memory.atomic.wait32 2 0
+	call push
+	call next
+
 ;; Core utility words
 
 .func exit
@@ -1226,6 +1235,15 @@ COPY:
 	.word COPY_CODEWORD
 .def PREV _COPY
 
+_WAIT:
+	.word PREV
+	.byte 4
+	.utf8 "WAIT"
+	.align
+WAIT:
+	.word WAIT_CODEWORD
+.def PREV _WAIT
+
 _EXIT:
 	.word PREV
 	.byte 4