Initial

1 files changed, 37 insertions, 0 deletions

diff --git a/crc32.cc b/crc32.cc
new file mode 100644
index 0000000..558d4ef
--- /dev/null
+++ b/crc32.cc
@@ -0,0 +1,37 @@
+/*
+ * Author: Copyright (C) Andrzej Surowiec 2012
+ *
+ *
+ * This file is part of Nitrokey.
+ *
+ * Nitrokey is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * Nitrokey is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Nitrokey. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "crc32.h"
+
+
+uint32_t Crc32 (uint32_t Crc, uint32_t Data)
+{
+int i;
+
+    Crc = Crc ^ Data;
+
+    for (i = 0; i < 32; i++)
+        if (Crc & 0x80000000)
+            Crc = (Crc << 1) ^ 0x04C11DB7;  // Polynomial used in STM32
+        else
+            Crc = (Crc << 1);
+
+    return (Crc);
+}