diff --git a/RELEASE-NOTES.md b/RELEASE-NOTES.md
index 72247f07..1cdc57de 100644
--- a/RELEASE-NOTES.md
+++ b/RELEASE-NOTES.md
@@ -26,6 +26,14 @@ Please report any bugs and incompatibilities in
     * New DC attribute: BIDI flag.
   1. Enhance commlcd engint to support more pixel type and synchronously update.
   1. New USVFB IAL engine and NEWGAL engine for web display server.
+  1. New type: `QDWORD` for a quauter of DWORD. This type is 16-bit long on
+64-bit architecture, and 8-bit long on 32-bit.
+  1. New macros for QDWORD:
+    * `MAKEDWORD`: Make a DWROD from four QDWORDs.
+    * `FIRST_QDWORD`: get the first (LSB) QDWORD from a DWORD.
+    * `SECOND_QDWORD`: get the second (LSB) QDWORD from a DWORD.
+    * `THIRD_QDWORD`: get the third (LSB) QDWORD from a DWORD.
+    * `FOURTH_QDWORD`: get the fourth (LSB) QDWORD from a DWORD.
 
 * BUGFIXING:
   1. handle `PNG_COLOR_TYPE_GRAY_ALPHA` color type of PNG files.
diff --git a/include/common.h b/include/common.h
index 4d4d815a..badbbcb2 100644
--- a/include/common.h
+++ b/include/common.h
@@ -587,6 +587,27 @@ typedef SDWORD_PTR SDWORD;
  */
 typedef signed int SDWORD32;
 
+#if SIZEOF_PTR == 8
+typedef unsigned short  QDWORD;
+#define QDWORD_SHIFT    16
+#else
+typedef unsigned char   QDWORD;
+#define QDWORD_SHIFT    8
+#endif
+
+#define MAKEDWORD(q1, q2, q3, q4) \
+    ((DWORD)( \
+        (((DWORD)(QDWORD)(q1))) | \
+        (((DWORD)((QDWORD)(q2))) << QDWORD_SHIFT) | \
+        (((DWORD)((QDWORD)(q3))) << (QDWORD_SHIFT*2)) | \
+        (((DWORD)((QDWORD)(q4))) << (QDWORD_SHIFT*3)) \
+    ))
+
+#define FIRST_QDWORD(dw)    ((QDWORD)(((DWORD)(dw))))
+#define SECOND_QDWORD(dw)   ((QDWORD)((((DWORD)(dw)) >> QDWORD_SHIFT)))
+#define THIRD_QDWORD(dw)    ((QDWORD)((((DWORD)(dw)) >> (QDWORD_SHIFT*2))))
+#define FOURTH_QDWORD(dw)   ((QDWORD)((((DWORD)(dw)) >> (QDWORD_SHIFT*3))))
+
 /**
  * \var UINT
  * \brief A type definition for unsigned integer.