2 files changed, 10 insertions, 2 deletions
diff --git a/src/library.js b/src/library.js
index 35466c10..5a429131 100644
--- a/src/library.js
+++ b/src/library.js
@@ -3184,7 +3184,9 @@ LibraryManager.library = {
      * mmap.
      */
     if (stream == -1) {
-      return allocate(num, 'i8', ALLOC_NORMAL);
+      var ptr = _malloc(num);
+      _memset(ptr, 0, num);
+      return ptr;
     }
     var info = FS.streams[stream];
     if (!info) return -1;
@@ -3195,6 +3197,7 @@ LibraryManager.library = {
 
   munmap: function(start, num) {
     _free(start);
+    return 0;
   },
 
   // TODO: Implement mremap.
diff --git a/src/preamble.js b/src/preamble.js
index 0b9288c4..5c5c21ea 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -462,9 +462,14 @@ function allocate(slab, types, allocator) {
 
   var ret = [_malloc, Runtime.stackAlloc, Runtime.staticAlloc][allocator === undefined ? ALLOC_STATIC : allocator](Math.max(size, singleType ? 1 : types.length));
 
+  if (zeroinit) {
+      _memset(ret, 0, size);
+      return ret;
+  }
+  
   var i = 0, type;
   while (i < size) {
-    var curr = zeroinit ? 0 : slab[i];
+    var curr = slab[i];
 
     if (typeof curr === 'function') {
       curr = Runtime.getFunctionIndex(curr);