diff --git a/include/Zydis/CommonTypes.h b/include/Zydis/CommonTypes.h
index d9726c6..cd51b5f 100644
--- a/include/Zydis/CommonTypes.h
+++ b/include/Zydis/CommonTypes.h
@@ -55,47 +55,54 @@
 #else 
     // No LibC, use compiler built-in types / macros.
 #   if defined(ZYDIS_MSVC)
-        typedef unsigned __int8     ZydisU8;
-        typedef unsigned __int16    ZydisU16;
-        typedef unsigned __int32    ZydisU32;
-        typedef unsigned __int64    ZydisU64;
-        typedef __int8              ZydisI8;
-        typedef __int16             ZydisI16;
-        typedef __int32             ZydisI32;
-        typedef __int64             ZydisI64;
-#       if _WIN64
-           typedef ZydisU64         ZydisUSize;
-           typedef ZydisI64         ZydisISize;
-#       else
-           typedef ZydisU32         ZydisUSize;
-           typedef ZydisI32         ZydisISize;
-#       endif
-#   elif defined(ZYDIS_GNUC)
-        typedef __UINT8_TYPE__      ZydisU8;
-        typedef __UINT16_TYPE__     ZydisU16;
-        typedef __UINT32_TYPE__     ZydisU32;
-        typedef __UINT64_TYPE__     ZydisU64;
-        typedef __INT8_TYPE__       ZydisI8;
-        typedef __INT16_TYPE__      ZydisI16;
-        typedef __INT32_TYPE__      ZydisI32;
-        typedef __INT64_TYPE__      ZydisI64;
-        typedef __SIZE_TYPE__       ZydisUSize;
-        typedef __PTRDIFF_TYPE__    ZydisISize;
+        typedef unsigned __int8  ZydisU8;
+        typedef unsigned __int16 ZydisU16;
+        typedef unsigned __int32 ZydisU32;
+        typedef unsigned __int64 ZydisU64;
+        typedef   signed __int8  ZydisI8;
+        typedef   signed __int16 ZydisI16;
+        typedef   signed __int32 ZydisI32;
+        typedef   signed __int64 ZydisI64;
+#       if _WIN64                
+           typedef ZydisU64      ZydisUSize;
+           typedef ZydisI64      ZydisISize;
+#       else                     
+           typedef ZydisU32      ZydisUSize;
+           typedef ZydisI32      ZydisISize;
+#       endif                    
+#   elif defined(ZYDIS_GNUC)     
+        typedef __UINT8_TYPE__   ZydisU8;
+        typedef __UINT16_TYPE__  ZydisU16;
+        typedef __UINT32_TYPE__  ZydisU32;
+        typedef __UINT64_TYPE__  ZydisU64;
+        typedef __INT8_TYPE__    ZydisI8;
+        typedef __INT16_TYPE__   ZydisI16;
+        typedef __INT32_TYPE__   ZydisI32;
+        typedef __INT64_TYPE__   ZydisI64;
+        typedef __SIZE_TYPE__    ZydisUSize;
+        typedef __PTRDIFF_TYPE__ ZydisISize;
 #   else
 #       error "Unsupported compiler for no-libc mode."
 #   endif
 #endif
 
-// Verify assumptions.
-ZYDIS_STATIC_ASSERT(sizeof(ZydisU8)  == 1);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisU16) == 2);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisU32) == 4);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisU64) == 8);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisI8)  == 1);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisI16) == 2);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisI32) == 4);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisI64) == 8);
-ZYDIS_STATIC_ASSERT(sizeof(ZydisUSize) == sizeof(ZydisISize));
+// Verify size assumptions.
+ZYDIS_STATIC_ASSERT(sizeof(ZydisU8   ) == 1            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisU16  ) == 2            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisU32  ) == 4            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisU64  ) == 8            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisI8   ) == 1            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisI16  ) == 2            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisI32  ) == 4            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisI64  ) == 8            );
+ZYDIS_STATIC_ASSERT(sizeof(ZydisUSize) == sizeof(void*));
+ZYDIS_STATIC_ASSERT(sizeof(ZydisISize) == sizeof(void*));
+
+// Verify signedness assumptions (relies on size checks above).
+ZYDIS_STATIC_ASSERT((ZydisI8 )-1 >> 1 < (ZydisI8 )((ZydisU8 )-1 >> 1));
+ZYDIS_STATIC_ASSERT((ZydisI16)-1 >> 1 < (ZydisI16)((ZydisU16)-1 >> 1));
+ZYDIS_STATIC_ASSERT((ZydisI32)-1 >> 1 < (ZydisI32)((ZydisU32)-1 >> 1));
+ZYDIS_STATIC_ASSERT((ZydisI64)-1 >> 1 < (ZydisI64)((ZydisU64)-1 >> 1));
 
 /* ============================================================================================== */
 /* NULL                                                                                           */
diff --git a/include/Zydis/Defines.h b/include/Zydis/Defines.h
index e847205..44341cd 100644
--- a/include/Zydis/Defines.h
+++ b/include/Zydis/Defines.h
@@ -137,7 +137,7 @@
 #       if __has_builtin(__builtin_unreachable)
 #           define ZYDIS_UNREACHABLE __builtin_unreachable()
 #       else
-#           define ZYDIS_UNREACHABLE
+#           define ZYDIS_UNREACHABLE for(;;)
 #       endif
 #   elif defined(ZYDIS_GCC) && ((__GNUC__ == 4 && __GNUC_MINOR__ > 4) || __GNUC__ > 4)
 #       define ZYDIS_UNREACHABLE __builtin_unreachable()
@@ -151,10 +151,10 @@
 #   elif defined(ZYDIS_MSVC)
 #       define ZYDIS_UNREACHABLE __assume(0)
 #   else
-#       define ZYDIS_UNREACHABLE
+#       define ZYDIS_UNREACHABLE for(;;)
 #   endif
 #elif defined(ZYDIS_NO_LIBC)
-#   define ZYDIS_UNREACHABLE
+#   define ZYDIS_UNREACHABLE for(;;)
 #else
 #   include <stdlib.h>
 #   define ZYDIS_UNREACHABLE { assert(0); abort(); }
diff --git a/include/Zydis/Zydis.h b/include/Zydis/Zydis.h
index ff1feef..67d6f52 100644
--- a/include/Zydis/Zydis.h
+++ b/include/Zydis/Zydis.h
@@ -125,7 +125,7 @@ enum ZydisFeatures
  * Use the macros provided in this file to extract the major, minor, patch and build part from the 
  * returned version value.
  */
-ZYDIS_EXPORT ZydisU64 ZydisGetVersion();
+ZYDIS_EXPORT ZydisU64 ZydisGetVersion(void);
 
 /**
  * @brief   Checks, if the specified feature is enabled in the current zydis library instance.
diff --git a/src/DecoderData.c b/src/DecoderData.c
index d12e942..f65f2d4 100644
--- a/src/DecoderData.c
+++ b/src/DecoderData.c
@@ -272,9 +272,9 @@ extern const ZydisDecoderTreeNode filtersMVEXE[][2];
 /* Decoder tree                                                                                   */
 /* ---------------------------------------------------------------------------------------------- */
 
-const ZydisDecoderTreeNode* ZydisDecoderTreeGetRootNode()
+const ZydisDecoderTreeNode* ZydisDecoderTreeGetRootNode(void)
 {
-    static const ZydisDecoderTreeNode root = { ZYDIS_NODETYPE_FILTER_OPCODE, 0x00000000 };  
+    static const ZydisDecoderTreeNode root = { ZYDIS_NODETYPE_FILTER_OPCODE, 0x0000 };  
     return &root;
 }
 
diff --git a/src/DecoderData.h b/src/DecoderData.h
index 784eab7..ec54d69 100644
--- a/src/DecoderData.h
+++ b/src/DecoderData.h
@@ -280,7 +280,7 @@ typedef struct ZydisInstructionEncodingInfo_
  *
  * @return  The root node of the instruction tree.
  */
-ZYDIS_NO_EXPORT const ZydisDecoderTreeNode* ZydisDecoderTreeGetRootNode();
+ZYDIS_NO_EXPORT const ZydisDecoderTreeNode* ZydisDecoderTreeGetRootNode(void);
 
 /**
  * @brief   Returns the child node of @c parent specified by @c index.
diff --git a/src/Zydis.c b/src/Zydis.c
index ab47bc4..6d46444 100644
--- a/src/Zydis.c
+++ b/src/Zydis.c
@@ -30,7 +30,7 @@
 /* Exported functions                                                                             */
 /* ============================================================================================== */
 
-ZydisU64 ZydisGetVersion()
+ZydisU64 ZydisGetVersion(void)
 {
     return ZYDIS_VERSION;
 }