From df8beba5855630e0d21ef853a7da34016f3bd56e Mon Sep 17 00:00:00 2001
From: Savva Mitrofanov <savvamtr@gmail.com>
Date: Wed, 28 Jun 2023 20:33:14 +0300
Subject: [PATCH] MdePkg/BaseLib: Correct CRC-16-ANSI implementation

The ANSI implementation assumes that initial value should be 0xFFFF and
the result shouldn't be inverted

Fixes: 92288f4 ("MdePkg/BaseLib: Add CRC16-ANSI and CRC32c implementations")
Signed-off-by: Savva Mitrofanov <savvamtr@gmail.com>
---
 MdePkg/Library/BaseLib/CheckSum.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/MdePkg/Library/BaseLib/CheckSum.c b/MdePkg/Library/BaseLib/CheckSum.c
index b6a0765731..57d324c82b 100644
--- a/MdePkg/Library/BaseLib/CheckSum.c
+++ b/MdePkg/Library/BaseLib/CheckSum.c
@@ -678,13 +678,13 @@ CalculateCrc16Ansi (
 
   Buf = Buffer;
 
-  Crc = ~InitialValue;
+  Crc = InitialValue;
 
   while (Length-- != 0) {
     Crc = mCrc16LookupTable[(Crc & 0xFF) ^ *(Buf++)] ^ (Crc >> 8);
   }
 
-  return ~Crc;
+  return Crc;
 }
 
 GLOBAL_REMOVE_IF_UNREFERENCED STATIC CONST UINT32  mCrc32cLookupTable[256] = {