From 79a788279b75083b065785793822bcf38aad1a62 Mon Sep 17 00:00:00 2001
From: Hayley Patton <theemacsshibe@gmail.com>
Date: Mon, 13 Nov 2023 15:18:49 +1100
Subject: [PATCH 1/2] Add Emscripten/WASM support

---
 .gitignore                        |  2 ++
 bin/makefile-emscripten.wasm-wasm | 19 +++++++++++++++++++
 bin/makeright                     |  5 +++++
 inc/maiko/platform.h              | 13 +++++++++++++
 src/timer.c                       |  5 +++++
 src/unixfork.c                    |  5 +++++
 src/xc.c                          | 10 ++++++++++
 7 files changed, 59 insertions(+)
 create mode 100644 bin/makefile-emscripten.wasm-wasm

diff --git a/.gitignore b/.gitignore
index 0111213..306defa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,6 +19,8 @@ cmake-build-*/**
 *.x86_64-x/**
 *.x86_64-sdl/**
 *.x86_64/**
+*.wasm/**
+*.wasm-wasm/**
 *.armv7l-x/**
 *.armv7l/**
 *.aarch64-x/**
diff --git a/bin/makefile-emscripten.wasm-wasm b/bin/makefile-emscripten.wasm-wasm
new file mode 100644
index 0000000..2007eec
--- /dev/null
+++ b/bin/makefile-emscripten.wasm-wasm
@@ -0,0 +1,19 @@
+# Options for Emscripten, WASM and SDL
+
+CC = emcc -sUSE_SDL=2 -sASYNCIFY -sALLOW_MEMORY_GROWTH $(CLANG_CFLAGS)
+
+XFILES = $(OBJECTDIR)sdl.o
+
+XFLAGS = -DSDL
+
+# OPTFLAGS is normally -O2.
+OPTFLAGS =  -O2 -g3
+DFLAGS = $(XFLAGS) -DRELEASE=351
+
+LD = emcc
+LDFLAGS = -sUSE_SDL=2 --preload-file $(SYSOUT)@full.sysout
+LDELDFLAGS =
+
+OBJECTDIR = ../$(RELEASENAME)/
+
+default	: ../$(OSARCHNAME)/lde ../$(OSARCHNAME)/ldesdl.js
diff --git a/bin/makeright b/bin/makeright
index 1fde522..156685c 100755
--- a/bin/makeright
+++ b/bin/makeright
@@ -74,6 +74,11 @@ case "$display" in
 	sdl)	releasename=${osversion}.${architecture}-${display}
 		ldename=ldesdl
 		;;
+	wasm)	osversion=emscripten
+		architecture=wasm
+		releasename=${osversion}.${architecture}-${display}
+		ldename=ldesdl.js
+		;;
 	*)	echo "display-option: $display is not supported."
 		exit
 		;;
diff --git a/inc/maiko/platform.h b/inc/maiko/platform.h
index 2fa747e..a69b21f 100644
--- a/inc/maiko/platform.h
+++ b/inc/maiko/platform.h
@@ -83,6 +83,19 @@
 #  define MAIKO_OS_DETECTED 1
 #endif
 
+#ifdef __EMSCRIPTEN__
+#  define MAIKO_OS_LINUX 1
+#  define MAIKO_OS_EMSCRIPTEN 1
+#  define MAIKO_OS_NAME "Emscripten"
+#  define MAIKO_EMULATE_TIMER_INTERRUPTS 1
+#  define MAIKO_EMULATE_ASYNC_INTERRUPTS 1
+#  define MAIKO_OS_UNIX_LIKE 1
+#  define MAIKO_OS_DETECTED
+#  define MAIKO_ARCH_NAME "WebAssembly"
+#  define MAIKO_ARCH_WORD_BITS 32
+#  define MAIKO_ARCH_DETECTED 1
+#endif
+
 /* __x86_64__: GNU C, __x86_64: Sun Studio, _M_AMD64: Visual Studio */
 #if defined(__x86_64__) || defined(__x86_64) || defined(_M_AMD64)
 #  define MAIKO_ARCH_X86_64 1
diff --git a/src/timer.c b/src/timer.c
index 5d75bb2..2cb14c2 100644
--- a/src/timer.c
+++ b/src/timer.c
@@ -73,6 +73,11 @@ extern int ether_fd;
 extern DspInterface currentdsp;
 #endif /* XWINDOW */
 
+#ifdef MAIKO_OS_EMSCRIPTEN
+/* We can't touch the system clock */
+#define settimeofday(tv, tz)
+#endif
+
 #define LISP_UNIX_TIME_DIFF 29969152
 #define LISP_ALTO_TIME_MASK 0x80000000
 #define UNIX_ALTO_TIME_DIFF 2177452800U
diff --git a/src/unixfork.c b/src/unixfork.c
index 3b9dce1..b35f1ef 100644
--- a/src/unixfork.c
+++ b/src/unixfork.c
@@ -45,6 +45,11 @@
 int flushing = 0;
 #endif
 
+#ifdef MAIKO_OS_EMSCRIPTEN
+/* We don't have any shell */
+#define getusershell() NULL
+#endif
+
 /* Used to communicate between Unix subprocesses and LISP */
 
 static long StartTime;  /* Time, for creating pipe filenames */
diff --git a/src/xc.c b/src/xc.c
index 5140042..644e00d 100644
--- a/src/xc.c
+++ b/src/xc.c
@@ -33,6 +33,10 @@
 #include <sys/time.h>
 #endif /* DOS */
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>         /* Defines emscripten_sleep */
+#endif /* __EMSCRIPTEN__ */
+
 #include "lispemul.h"
 #include "emlglob.h"
 #include "address.h"
@@ -183,6 +187,9 @@ static int pseudoTimerAsyncCountdown = MAIKO_TIMER_ASYNC_EMULATION_INSNS_COUNTDO
 
 void dispatch(void) {
   InstPtr pccache;
+#ifdef __EMSCRIPTEN__
+  int cycles = 0;
+#endif
 
 #if defined(OPDISP)
   static const void* optable[256] = {
@@ -261,6 +268,9 @@ op_ufn : {
 /* DISPATCH "LOOP" */
 
 nextopcode:
+#ifdef __EMSCRIPTEN__
+  if (++cycles % 1000000 == 0) emscripten_sleep(1);
+#endif
 #ifdef MYOPTRACE
   if ((struct fnhead *)NativeAligned4FromLAddr(0x2ed600) == FuncObj) {
     quick_stack_check();

From 7b2cf44c7cca62e5faf2efa5b4912da79cee0ffc Mon Sep 17 00:00:00 2001
From: Hayley Patton <theemacsshibe@gmail.com>
Date: Mon, 13 Nov 2023 15:30:19 +1100
Subject: [PATCH 2/2] Add ldesdl.html

---
 .gitignore                  |  1 +
 emscripten.wasm/ldesdl.html | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 emscripten.wasm/ldesdl.html

diff --git a/.gitignore b/.gitignore
index 306defa..8e0d861 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,6 +20,7 @@ cmake-build-*/**
 *.x86_64-sdl/**
 *.x86_64/**
 *.wasm/**
+!emscripten.wasm/ldesdl.html
 *.wasm-wasm/**
 *.armv7l-x/**
 *.armv7l/**
diff --git a/emscripten.wasm/ldesdl.html b/emscripten.wasm/ldesdl.html
new file mode 100644
index 0000000..3ddffcd
--- /dev/null
+++ b/emscripten.wasm/ldesdl.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<!-- Based on https://github.com/timhutton/sdl-canvas-wasm/blob/main/index.html -->
+<html>
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+  </head>
+  <body>
+    <div style="text-align: center;">
+      <canvas id="canvas" oncontextmenu="event.preventDefault()"></canvas>
+    </div>
+    <script type="text/javascript">
+      var Module = {
+          arguments: ["full.sysout"],
+          canvas: (function() { return document.getElementById('canvas'); })()
+      };
+    </script>
+    <script src="ldesdl.js"></script>
+  </body>
+</html>