diff --git a/common/Tiano/EfiTianoDecompress.c b/common/Tiano/EfiTianoDecompress.c
index 156392c..7f2f31a 100644
--- a/common/Tiano/EfiTianoDecompress.c
+++ b/common/Tiano/EfiTianoDecompress.c
@@ -100,10 +100,10 @@ Returns: (VOID)
 
 --*/
 {
-    Sd->mBitBuf = (UINT32)(Sd->mBitBuf << NumOfBits);
+    Sd->mBitBuf = (UINT32) (((UINT64)Sd->mBitBuf) << NumOfBits);
 
     while (NumOfBits > Sd->mBitCount) {
-        Sd->mBitBuf |= (UINT32)(Sd->mSubBitBuf << (NumOfBits = (UINT16)(NumOfBits - Sd->mBitCount)));
+        Sd->mBitBuf |= (UINT32) (((UINT64)Sd->mSubBitBuf) << (NumOfBits = (UINT16) (NumOfBits - Sd->mBitCount)));
 
         if (Sd->mCompSize > 0) {
             //