diff --git a/smc-command/smc.c b/smc-command/smc.c
index ff1e48b..e8add92 100644
--- a/smc-command/smc.c
+++ b/smc-command/smc.c
@@ -37,7 +37,7 @@ UInt32 _strtoul(char *str, int size, int base)
         if (base == 16)
             total += str[i] << (size - 1 - i) * 8;
         else
-           total += (unsigned char) (str[i] << (size - 1 - i) * 8);
+           total += ((unsigned char) (str[i]) << (size - 1 - i) * 8);
     }
     return total;
 }