diff --git a/ChangeLog b/ChangeLog
index 6223f2f862..f7a5c1c591 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Mar 12 09:24:24 2009  Tanaka Akira  <akr@fsij.org>
+
+	* transcode_data.h: suppress warnings of overflow.
+
 Thu Mar 12 09:15:14 2009  Tanaka Akira  <akr@fsij.org>
 
 	* include/ruby/encoding.h: suppress warnings of overflow.
diff --git a/transcode_data.h b/transcode_data.h
index a26fb42034..cbceb0c7ee 100644
--- a/transcode_data.h
+++ b/transcode_data.h
@@ -44,9 +44,9 @@
 
 #define o1(b1)		(PType((((unsigned char)(b1))<<8)|ONEbt))
 #define o2(b1,b2)	(PType((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|TWObt))
-#define o3(b1,b2,b3)	(PType(((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|(((unsigned char)(b3))<<24)|THREEbt)&0xffffffffU))
+#define o3(b1,b2,b3)	(PType(((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|(((unsigned int)(unsigned char)(b3))<<24)|THREEbt)&0xffffffffU))
 #define o4(b0,b1,b2,b3)	(PType(((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|(((unsigned char)(b3))<<24)|((((unsigned char)(b0))&0x07)<<5)|FOURbt)&0xffffffffU))
-#define g4(b0,b1,b2,b3) (PType(((((unsigned char)(b0))<<8)|(((unsigned char)(b2))<<16)|((((unsigned char)(b1))&0x0f)<<24)|((((unsigned char)(b3))&0x0f)<<28)|GB4bt)&0xffffffffU))
+#define g4(b0,b1,b2,b3) (PType(((((unsigned char)(b0))<<8)|(((unsigned char)(b2))<<16)|((((unsigned char)(b1))&0x0f)<<24)|((((unsigned int)(unsigned char)(b3))&0x0f)<<28)|GB4bt)&0xffffffffU))
 
 #define getBT1(a)	(((a)>> 8)&0xFF)
 #define getBT2(a)	(((a)>>16)&0xFF)