EM_ASM_INT and EM_ASM_DOUBLE, which allow input and output values from EM_ASM; fixes #1819

2 files changed, 25 insertions, 6 deletions

diff --git a/src/library.js b/src/library.js
index 9db99c6c..066a060f 100644
--- a/src/library.js
+++ b/src/library.js
@@ -8676,12 +8676,19 @@ LibraryManager.library = {
   },
 
   emscripten_asm_const: function(code) {
-    // code is a constant string on the heap, so we can cache these
-    if (!Runtime.asmConstCache) Runtime.asmConstCache = {};
-    var func = Runtime.asmConstCache[code];
-    if (func) return func();
-    func = Runtime.asmConstCache[code] = eval('(function(){ ' + Pointer_stringify(code) + ' })'); // new Function does not allow upvars in node
-    return func();
+    Runtime.getAsmConst(code, 0)();
+  },
+
+  emscripten_asm_const_int__jsargs: true,
+  emscripten_asm_const_int: function(code) {
+    var args = Array.prototype.slice.call(arguments, 1);
+    return Runtime.getAsmConst(code, args.length).apply(null, args) | 0;
+  },
+
+  emscripten_asm_const_double__jsargs: true,
+  emscripten_asm_const_double: function(code) {
+    var args = Array.prototype.slice.call(arguments, 1);
+    return +Runtime.getAsmConst(code, args.length).apply(null, args);
   },
 
   emscripten_get_now: function() {
diff --git a/src/runtime.js b/src/runtime.js
index 786ae021..dedaf5ea 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -381,6 +381,18 @@ var Runtime = {
 #endif
   },
 
+  getAsmConst: function(code, numArgs) {
+    // code is a constant string on the heap, so we can cache these
+    if (!Runtime.asmConstCache) Runtime.asmConstCache = {};
+    var func = Runtime.asmConstCache[code];
+    if (func) return func;
+    var args = [];
+    for (var i = 0; i < numArgs; i++) {
+      args.push(String.fromCharCode(36) + i); // $0, $1 etc
+    }
+    return Runtime.asmConstCache[code] = eval('(function(' + args.join(',') + '){ ' + Pointer_stringify(code) + ' })'); // new Function does not allow upvars in node
+  },
+
   warnOnce: function(text) {
     if (!Runtime.warnOnce.shown) Runtime.warnOnce.shown = {};
     if (!Runtime.warnOnce.shown[text]) {