diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 6e66b6e..3e037d7 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -149,8 +149,7 @@
 
   // Skip barrier if writing a smi.
   ASSERT_EQ(0, kSmiTag);
-  test(value, Immediate(kSmiTagMask));
-  j(zero, &done, Label::kNear);
+  JumpIfSmi(value, &done, Label::kNear);
 
   InNewSpace(object, value, equal, &done, Label::kNear);
 
@@ -195,8 +194,7 @@
 
   // Skip barrier if writing a smi.
   ASSERT_EQ(0, kSmiTag);
-  test(value, Immediate(kSmiTagMask));
-  j(zero, &done);
+  JumpIfSmi(value, &done, Label::kNear);
 
   InNewSpace(object, value, equal, &done);
 
@@ -279,6 +277,16 @@
 }
 
 
+void MacroAssembler::CheckFastElements(Register map,
+                                       Label* fail,
+                                       Label::Distance distance) {
+  STATIC_ASSERT(JSObject::FAST_ELEMENTS == 0);
+  cmpb(FieldOperand(map, Map::kBitField2Offset),
+       Map::kMaximumBitField2FastElementValue);
+  j(above, fail, distance);
+}
+
+
 void MacroAssembler::CheckMap(Register obj,
                               Handle<Map> map,
                               Label* fail,
@@ -330,8 +338,9 @@
                                             Register scratch,
                                             Label* fail) {
   movzx_b(scratch, FieldOperand(map, Map::kInstanceTypeOffset));
-  sub(Operand(scratch), Immediate(FIRST_JS_OBJECT_TYPE));
-  cmp(scratch, LAST_JS_OBJECT_TYPE - FIRST_JS_OBJECT_TYPE);
+  sub(Operand(scratch), Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
+  cmp(scratch,
+      LAST_NONCALLABLE_SPEC_OBJECT_TYPE - FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
   j(above, fail);
 }
 
@@ -353,8 +362,7 @@
 
 void MacroAssembler::AbortIfNotNumber(Register object) {
   Label ok;
-  test(object, Immediate(kSmiTagMask));
-  j(zero, &ok);
+  JumpIfSmi(object, &ok);
   cmp(FieldOperand(object, HeapObject::kMapOffset),
       isolate()->factory()->heap_number_map());
   Assert(equal, "Operand not a number");
@@ -726,6 +734,104 @@
 }
 
 
+void MacroAssembler::LoadFromNumberDictionary(Label* miss,
+                                              Register elements,
+                                              Register key,
+                                              Register r0,
+                                              Register r1,
+                                              Register r2,
+                                              Register result) {
+  // Register use:
+  //
+  // elements - holds the slow-case elements of the receiver and is unchanged.
+  //
+  // key      - holds the smi key on entry and is unchanged.
+  //
+  // Scratch registers:
+  //
+  // r0 - holds the untagged key on entry and holds the hash once computed.
+  //
+  // r1 - used to hold the capacity mask of the dictionary
+  //
+  // r2 - used for the index into the dictionary.
+  //
+  // result - holds the result on exit if the load succeeds and we fall through.
+
+  Label done;
+
+  // Compute the hash code from the untagged key.  This must be kept in sync
+  // with ComputeIntegerHash in utils.h.
+  //
+  // hash = ~hash + (hash << 15);
+  mov(r1, r0);
+  not_(r0);
+  shl(r1, 15);
+  add(r0, Operand(r1));
+  // hash = hash ^ (hash >> 12);
+  mov(r1, r0);
+  shr(r1, 12);
+  xor_(r0, Operand(r1));
+  // hash = hash + (hash << 2);
+  lea(r0, Operand(r0, r0, times_4, 0));
+  // hash = hash ^ (hash >> 4);
+  mov(r1, r0);
+  shr(r1, 4);
+  xor_(r0, Operand(r1));
+  // hash = hash * 2057;
+  imul(r0, r0, 2057);
+  // hash = hash ^ (hash >> 16);
+  mov(r1, r0);
+  shr(r1, 16);
+  xor_(r0, Operand(r1));
+
+  // Compute capacity mask.
+  mov(r1, FieldOperand(elements, NumberDictionary::kCapacityOffset));
+  shr(r1, kSmiTagSize);  // convert smi to int
+  dec(r1);
+
+  // Generate an unrolled loop that performs a few probes before giving up.
+  const int kProbes = 4;
+  for (int i = 0; i < kProbes; i++) {
+    // Use r2 for index calculations and keep the hash intact in r0.
+    mov(r2, r0);
+    // Compute the masked index: (hash + i + i * i) & mask.
+    if (i > 0) {
+      add(Operand(r2), Immediate(NumberDictionary::GetProbeOffset(i)));
+    }
+    and_(r2, Operand(r1));
+
+    // Scale the index by multiplying by the entry size.
+    ASSERT(NumberDictionary::kEntrySize == 3);
+    lea(r2, Operand(r2, r2, times_2, 0));  // r2 = r2 * 3
+
+    // Check if the key matches.
+    cmp(key, FieldOperand(elements,
+                          r2,
+                          times_pointer_size,
+                          NumberDictionary::kElementsStartOffset));
+    if (i != (kProbes - 1)) {
+      j(equal, &done);
+    } else {
+      j(not_equal, miss);
+    }
+  }
+
+  bind(&done);
+  // Check that the value is a normal propety.
+  const int kDetailsOffset =
+      NumberDictionary::kElementsStartOffset + 2 * kPointerSize;
+  ASSERT_EQ(NORMAL, 0);
+  test(FieldOperand(elements, r2, times_pointer_size, kDetailsOffset),
+       Immediate(PropertyDetails::TypeField::mask() << kSmiTagSize));
+  j(not_zero, miss);
+
+  // Get the value at the masked, scaled index.
+  const int kValueOffset =
+      NumberDictionary::kElementsStartOffset + kPointerSize;
+  mov(result, FieldOperand(elements, r2, times_pointer_size, kValueOffset));
+}
+
+
 void MacroAssembler::LoadAllocationTopHelper(Register result,
                                              Register scratch,
                                              AllocationFlags flags) {
@@ -1165,8 +1271,7 @@
                                              Register scratch,
                                              Label* miss) {
   // Check that the receiver isn't a smi.
-  test(function, Immediate(kSmiTagMask));
-  j(zero, miss);
+  JumpIfSmi(function, miss);
 
   // Check that the function really is a function.
   CmpObjectType(function, JS_FUNCTION_TYPE, result);
@@ -1405,32 +1510,30 @@
 }
 
 
-void MacroAssembler::PrepareCallApiFunction(int argc, Register scratch) {
+void MacroAssembler::PrepareCallApiFunction(int argc) {
   if (kReturnHandlesDirectly) {
     EnterApiExitFrame(argc);
     // When handles are returned directly we don't have to allocate extra
     // space for and pass an out parameter.
+    if (emit_debug_code()) {
+      mov(esi, Immediate(BitCast<int32_t>(kZapValue)));
+    }
   } else {
     // We allocate two additional slots: return value and pointer to it.
     EnterApiExitFrame(argc + 2);
 
     // The argument slots are filled as follows:
     //
-    //   n + 1: output cell
+    //   n + 1: output slot
     //   n: arg n
     //   ...
     //   1: arg1
-    //   0: pointer to the output cell
-    //
-    // Note that this is one more "argument" than the function expects
-    // so the out cell will have to be popped explicitly after returning
-    // from the function. The out cell contains Handle.
+    //   0: pointer to the output slot
 
-    // pointer to out cell.
-    lea(scratch, Operand(esp, (argc + 1) * kPointerSize));
-    mov(Operand(esp, 0 * kPointerSize), scratch);  // output.
+    lea(esi, Operand(esp, (argc + 1) * kPointerSize));
+    mov(Operand(esp, 0 * kPointerSize), esi);
     if (emit_debug_code()) {
-      mov(Operand(esp, (argc + 1) * kPointerSize), Immediate(0));  // out cell.
+      mov(Operand(esi, 0), Immediate(0));
     }
   }
 }
@@ -1454,9 +1557,9 @@
   call(function->address(), RelocInfo::RUNTIME_ENTRY);
 
   if (!kReturnHandlesDirectly) {
-    // The returned value is a pointer to the handle holding the result.
-    // Dereference this to get to the location.
-    mov(eax, Operand(eax, 0));
+    // PrepareCallApiFunction saved pointer to the output slot into
+    // callee-save register esi.
+    mov(eax, Operand(esi, 0));
   }
 
   Label empty_handle;
@@ -1748,12 +1851,9 @@
 void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
   if (context_chain_length > 0) {
     // Move up the chain of contexts to the context containing the slot.
-    mov(dst, Operand(esi, Context::SlotOffset(Context::CLOSURE_INDEX)));
-    // Load the function context (which is the incoming, outer context).
-    mov(dst, FieldOperand(dst, JSFunction::kContextOffset));
+    mov(dst, Operand(esi, Context::SlotOffset(Context::PREVIOUS_INDEX)));
     for (int i = 1; i < context_chain_length; i++) {
-      mov(dst, Operand(dst, Context::SlotOffset(Context::CLOSURE_INDEX)));
-      mov(dst, FieldOperand(dst, JSFunction::kContextOffset));
+      mov(dst, Operand(dst, Context::SlotOffset(Context::PREVIOUS_INDEX)));
     }
   } else {
     // Slot is in the current function context.  Move it into the
@@ -1762,14 +1862,14 @@
     mov(dst, esi);
   }
 
-  // We should not have found a 'with' context by walking the context chain
+  // We should not have found a with context by walking the context chain
   // (i.e., the static scope chain and runtime context chain do not agree).
   // A variable occurring in such a scope should have slot type LOOKUP and
   // not CONTEXT.
   if (emit_debug_code()) {
-    cmp(dst, Operand(dst, Context::SlotOffset(Context::FCONTEXT_INDEX)));
-    Check(equal, "Yo dawg, I heard you liked function contexts "
-                 "so I put function contexts in all your contexts");
+    cmp(FieldOperand(dst, HeapObject::kMapOffset),
+        isolate()->factory()->with_context_map());
+    Check(not_equal, "Variable resolved to with context.");
   }
 }
 
@@ -1944,6 +2044,9 @@
         Immediate(factory->fixed_array_map()));
     j(equal, &ok);
     cmp(FieldOperand(elements, HeapObject::kMapOffset),
+        Immediate(factory->fixed_double_array_map()));
+    j(equal, &ok);
+    cmp(FieldOperand(elements, HeapObject::kMapOffset),
         Immediate(factory->fixed_cow_array_map()));
     j(equal, &ok);
     Abort("JSObject with fast elements map has slow elements");
@@ -2048,8 +2151,7 @@
   ASSERT_EQ(0, kSmiTag);
   mov(scratch1, Operand(object1));
   and_(scratch1, Operand(object2));
-  test(scratch1, Immediate(kSmiTagMask));
-  j(zero, failure);
+  JumpIfSmi(scratch1, failure);
 
   // Load instance type for both strings.
   mov(scratch1, FieldOperand(object1, HeapObject::kMapOffset));