Incremental mode now works for x64. The only difference

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
===================================================================
--- src/ia32/macro-assembler-ia32.h	(revision 8221)
+++ src/ia32/macro-assembler-ia32.h	(working copy)
@@ -93,17 +93,25 @@
                      Label* condition_met,
                      Label::Distance condition_met_distance = Label::kFar);
 
-  void InNewSpace(Register object,
-                  Register scratch,
-                  Condition cc,
-                  Label* condition_met,
-                  Label::Distance condition_met_distance = Label::kFar);
+  // Check if object is in new space.  Jumps if the object is not in new space.
+  // The register scratch can be object itself, but it will be clobbered.
+  void JumpIfNotInNewSpace(Register object,
+                           Register scratch,
+                           Label* branch,
+                           Label::Distance distance = Label::kFar) {
+    InNewSpace(object, scratch, zero, branch, distance);
+  }
 
+  // Check if object is in new space.  Jumps if the object is in new space.
+  // The register scratch can be object itself, but it will be clobbered.
+  void JumpIfInNewSpace(Register object,
+                        Register scratch,
+                        Label* branch,
+                        Label::Distance distance = Label::kFar) {
+    InNewSpace(object, scratch, not_zero, branch, distance);
+  }
+
   // Check if an object has a given incremental marking color.  Also uses ecx!
-  // The color bits are found by splitting the address at the bit offset
-  // indicated by the mask: bits that are zero in the mask are used for the
-  // address of the bitmap, and bits that are one in the mask are used for the
-  // index of the bit.
   void HasColor(Register object,
                 Register scratch0,
                 Register scratch1,
@@ -785,6 +793,13 @@
                                                     Register scratch,
                                                     bool gc_allowed);
 
+  // Helper for implementing JumpIfNotInNewSpace and JumpIfInNewSpace.
+  void InNewSpace(Register object,
+                  Register scratch,
+                  Condition cc,
+                  Label* condition_met,
+                  Label::Distance condition_met_distance = Label::kFar);
+
   // Helper for finding the mark bits for an address.  Afterwards, the
   // bitmap register points at the word with the mark bits and the mask
   // the position of the first bit.  Uses ecx as scratch and leaves addr_reg