diff --git a/src/compile-powerpc.S b/src/compile-powerpc.S
index b732f893ea..b1cd0ba928 100644
--- a/src/compile-powerpc.S
+++ b/src/compile-powerpc.S
@@ -24,12 +24,12 @@
 #  define GLOBAL(x) x   
 #endif
       
-#define THREAD_STACK 2152
-#define THREAD_CONTINUATION 2156
+#define THREAD_STACK 2144
+#define THREAD_CONTINUATION 2148
 #define THREAD_EXCEPTION 44
-#define THREAD_EXCEPTION_STACK_ADJUSTMENT 2160
-#define THREAD_EXCEPTION_OFFSET 2164
-#define THREAD_EXCEPTION_HANDLER 2168
+#define THREAD_EXCEPTION_STACK_ADJUSTMENT 2152
+#define THREAD_EXCEPTION_OFFSET 2156
+#define THREAD_EXCEPTION_HANDLER 2160
 
 #define CONTINUATION_NEXT 4
 #define CONTINUATION_ADDRESS 16
diff --git a/src/compile.cpp b/src/compile.cpp
index 53e31367f1..83c4532a47 100644
--- a/src/compile.cpp
+++ b/src/compile.cpp
@@ -2662,6 +2662,12 @@ makeNew64(Thread* t, object class_)
   return reinterpret_cast<uintptr_t>(makeNew(t, class_));
 }
 
+uint64_t
+getJClass64(Thread* t, object class_)
+{
+  return reinterpret_cast<uintptr_t>(getJClass(t, class_));
+}
+
 void
 gcIfNecessary(MyThread* t)
 {
@@ -4401,7 +4407,7 @@ compile(MyThread* t, Frame* initialFrame, unsigned ip,
           frame->pushObject
             (c->call
              (c->constant
-              (getThunk(t, getJClassThunk), Compiler::AddressType),
+              (getThunk(t, getJClass64Thunk), Compiler::AddressType),
               0,
               frame->trace(0, 0),
               BytesPerWord,
diff --git a/src/thunks.cpp b/src/thunks.cpp
index 9de7aaf263..4d863ecca4 100644
--- a/src/thunks.cpp
+++ b/src/thunks.cpp
@@ -48,5 +48,5 @@ THUNK(instanceOf64)
 THUNK(makeNewGeneral64)
 THUNK(makeNew64)
 THUNK(set)
-THUNK(getJClass)
+THUNK(getJClass64)
 THUNK(gcIfNecessary)