diff --git a/src/arch/power/isa/bitfields.isa b/src/arch/power/isa/bitfields.isa
index 6cc67dd58f..3ea6d8c366 100644
--- a/src/arch/power/isa/bitfields.isa
+++ b/src/arch/power/isa/bitfields.isa
@@ -34,10 +34,14 @@
 // are reversed sometimes. Not sure of a fix to this though...
 
 // Opcode fields
-def bitfield OPCODE        <31:26>;
-def bitfield X_XO          <10:0>;
-def bitfield XO_XO         <10:1>;
+def bitfield PO            <31:26>;
 def bitfield A_XO          <5:1>;
+def bitfield DS_XO         <1:0>;
+def bitfield X_XO          <10:1>;
+def bitfield XFL_XO        <10:1>;
+def bitfield XFX_XO        <10:1>;
+def bitfield XL_XO         <10:1>;
+def bitfield XO_XO         <9:1>;
 
 // Register fields
 def bitfield RA            <20:16>;
diff --git a/src/arch/power/isa/decoder.isa b/src/arch/power/isa/decoder.isa
index a42861b75f..1a8b3757e3 100644
--- a/src/arch/power/isa/decoder.isa
+++ b/src/arch/power/isa/decoder.isa
@@ -34,7 +34,7 @@
 // Power ISA v3.0B has been used for instruction formats, opcode numbers,
 // opcode field names, register names, etc.
 //
-decode OPCODE default Unknown::unknown() {
+decode PO default Unknown::unknown() {
 
     format IntImmArithOp {
         7: mulli({{
diff --git a/src/arch/power/isa/formats/unimp.isa b/src/arch/power/isa/formats/unimp.isa
index fef28ce5b1..a3f4692c89 100644
--- a/src/arch/power/isa/formats/unimp.isa
+++ b/src/arch/power/isa/formats/unimp.isa
@@ -112,7 +112,7 @@ output exec {{
                                Trace::InstRecord *traceData) const
     {
         panic("attempt to execute unimplemented instruction '%s' "
-              "(inst 0x%08x, opcode 0x%x, binary:%s)", mnemonic, machInst, OPCODE,
+              "(inst 0x%08x, opcode 0x%x, binary:%s)", mnemonic, machInst, PO,
               inst2string(machInst));
         return std::make_shared<UnimplementedOpcodeFault>();
     }
diff --git a/src/arch/power/isa/formats/unknown.isa b/src/arch/power/isa/formats/unknown.isa
index d0f81f1ff7..d83f79cf22 100644
--- a/src/arch/power/isa/formats/unknown.isa
+++ b/src/arch/power/isa/formats/unknown.isa
@@ -63,7 +63,7 @@ output decoder {{
             Addr pc, const Loader::SymbolTable *symtab) const
     {
         return csprintf("%-10s (inst 0x%x, opcode 0x%x, binary:%s)",
-                        "unknown", machInst, OPCODE, inst2string(machInst));
+                        "unknown", machInst, PO, inst2string(machInst));
     }
 }};
 
@@ -73,7 +73,7 @@ output exec {{
     {
         panic("attempt to execute unknown instruction at %#x"
               "(inst 0x%08x, opcode 0x%x, binary: %s)",
-              xc->pcState().pc(), machInst, OPCODE, inst2string(machInst));
+              xc->pcState().pc(), machInst, PO, inst2string(machInst));
         return std::make_shared<UnimplementedOpcodeFault>();
     }
 }};