diff --git a/src/arch/power/isa/bitfields.isa b/src/arch/power/isa/bitfields.isa
index dfe4683dcf..3bfea53065 100644
--- a/src/arch/power/isa/bitfields.isa
+++ b/src/arch/power/isa/bitfields.isa
@@ -38,6 +38,8 @@ def bitfield PO            <31:26>;
 def bitfield A_XO          <5:1>;
 def bitfield DS_XO         <1:0>;
 def bitfield DX_XO         <5:1>;
+def bitfield MD_XO         <4:2>;
+def bitfield MDS_XO        <4:1>;
 def bitfield VA_XO         <5:0>;
 def bitfield X_XO          <10:1>;
 def bitfield XFL_XO        <10:1>;
diff --git a/src/arch/power/types.hh b/src/arch/power/types.hh
index 41b166fec4..b0d943b1fd 100644
--- a/src/arch/power/types.hh
+++ b/src/arch/power/types.hh
@@ -49,7 +49,9 @@ BitUnion32(ExtMachInst)
     Bitfield<15, 11> sh;
     Bitfield<1>      shn;
     Bitfield<10,  6> mb;
+    Bitfield<5>      mbn;
     Bitfield< 5,  1> me;
+    Bitfield<5>      men;
 
     // Immediate fields
     Bitfield<15,  0> si;