diff --git a/MdeModulePkg/Universal/RegularExpressionDxe/OnigurumaUefiPort.c b/MdeModulePkg/Universal/RegularExpressionDxe/OnigurumaUefiPort.c
index 2b2b0d420d..9aa7b0a68e 100644
--- a/MdeModulePkg/Universal/RegularExpressionDxe/OnigurumaUefiPort.c
+++ b/MdeModulePkg/Universal/RegularExpressionDxe/OnigurumaUefiPort.c
@@ -93,6 +93,6 @@ void* memcpy (void *dest, const void *src, unsigned int count)
 
 void* memset (void *dest, char ch, unsigned int count)
 {
-  return SetMem (dest, ch, count);
+  return SetMem (dest, count, ch);
 }