diff --git a/include/openflow/nicira-ext.h b/include/openflow/nicira-ext.h
index 8140edfc4..97f547883 100644
--- a/include/openflow/nicira-ext.h
+++ b/include/openflow/nicira-ext.h
@@ -864,7 +864,8 @@ OFP_ASSERT(sizeof(struct nx_action_note) == 16);
 #define NXM_NX_REG(IDX)   NXM_HEADER  (0x0001, IDX, 4)
 #define NXM_NX_REG_W(IDX) NXM_HEADER_W(0x0001, IDX, 4)
 #define NXM_NX_REG_IDX(HEADER) NXM_FIELD(HEADER)
-#define NXM_IS_NX_REG(HEADER) (!((((HEADER) ^ NXM_NX_REG(0))) & 0xffffe0ff))
+#define NXM_IS_NX_REG(HEADER) (!((((HEADER) ^ NXM_NX_REG0)) & 0xffffe1ff))
+#define NXM_IS_NX_REG_W(HEADER) (!((((HEADER) ^ NXM_NX_REG0_W)) & 0xffffe1ff))
 #define NXM_NX_REG0       NXM_HEADER  (0x0001, 0, 4)
 #define NXM_NX_REG0_W     NXM_HEADER_W(0x0001, 0, 4)
 #define NXM_NX_REG1       NXM_HEADER  (0x0001, 1, 4)