diff --git a/src/core/arm/dyncom/arm_dyncom_dec.cpp b/src/core/arm/dyncom/arm_dyncom_dec.cpp
index dcfcd6561c..b66960620e 100644
--- a/src/core/arm/dyncom/arm_dyncom_dec.cpp
+++ b/src/core/arm/dyncom/arm_dyncom_dec.cpp
@@ -5,6 +5,31 @@
 #include "core/arm/dyncom/arm_dyncom_dec.h"
 #include "core/arm/skyeye_common/armsupp.h"
 
+namespace {
+struct InstructionSetEncodingItem {
+    const char* name;
+    int attribute_value;
+    int version;
+    u32 content[21];
+};
+
+// ARM versions
+enum {
+    INVALID = 0,
+    ARMALL,
+    ARMV4,
+    ARMV4T,
+    ARMV5T,
+    ARMV5TE,
+    ARMV5TEJ,
+    ARMV6,
+    ARM1176JZF_S,
+    ARMVFP2,
+    ARMVFP3,
+    ARMV6K,
+};
+}
+
 // clang-format off
 const InstructionSetEncodingItem arm_instruction[] = {
     { "vmla", 5, ARMVFP2,      { 23, 27, 0x1C, 20, 21, 0x0, 9, 11, 0x5, 6, 6, 0, 4, 4, 0 }},
diff --git a/src/core/arm/dyncom/arm_dyncom_dec.h b/src/core/arm/dyncom/arm_dyncom_dec.h
index 1dcf7ecd14..db292a9af3 100644
--- a/src/core/arm/dyncom/arm_dyncom_dec.h
+++ b/src/core/arm/dyncom/arm_dyncom_dec.h
@@ -9,28 +9,3 @@
 enum class ARMDecodeStatus { SUCCESS, FAILURE };
 
 ARMDecodeStatus DecodeARMInstruction(u32 instr, int* idx);
-
-struct InstructionSetEncodingItem {
-    const char* name;
-    int attribute_value;
-    int version;
-    u32 content[21];
-};
-
-// ARM versions
-enum {
-    INVALID = 0,
-    ARMALL,
-    ARMV4,
-    ARMV4T,
-    ARMV5T,
-    ARMV5TE,
-    ARMV5TEJ,
-    ARMV6,
-    ARM1176JZF_S,
-    ARMVFP2,
-    ARMVFP3,
-    ARMV6K,
-};
-
-extern const InstructionSetEncodingItem arm_instruction[];