MdeModulePkg/PrintLib: Fix possible negative value left shift

[mirror_edk2.git] / MdeModulePkg / Library / DxePrintLibPrint2Protocol / PrintLib.c

diff --git a/MdeModulePkg/Library/DxePrintLibPrint2Protocol/PrintLib.c b/MdeModulePkg/Library/DxePrintLibPrint2Protocol/PrintLib.c
index b58db8e011a8517c741e947b2990c29522242488..56534e56c3a1e06d554561caf99b5d5e8de9ed80 100644 (file)
--- a/MdeModulePkg/Library/DxePrintLibPrint2Protocol/PrintLib.c
+++ b/MdeModulePkg/Library/DxePrintLibPrint2Protocol/PrintLib.c
@@ -2108,7 +2108,7 @@ InternalPrintLibSPrintMarker (
     // Copy the string into the output buffer performing the required type conversions\r
     //\r
     while (Index < Count) {\r
-      ArgumentCharacter = ((*ArgumentString & 0xff) | (*(ArgumentString + 1) << 8)) & ArgumentMask;\r
+      ArgumentCharacter = ((*ArgumentString & 0xff) | (((UINT8)*(ArgumentString + 1)) << 8)) & ArgumentMask;\r
 \r
       LengthToReturn += (1 * BytesPerOutputCharacter);\r
       if ((Flags & COUNT_ONLY_NO_PRINT) == 0 && Buffer != NULL) {\r