更新硬件SDK

sdk/合宙/air780e/csdk/luatos-soc-2022/thirdparty/littlefs/lfs_util.c

@@ -0,0 +1,59 @@
+/*
+ * lfs util functions
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include "lfs_util.h"
+
+// Only compile if user does not provide custom config
+#ifndef LFS_CONFIG
+
+
+// Software CRC implementation with small lookup table
+uint32_t lfs_crc(uint32_t crc, const void *buffer, size_t size) {
+    static uint32_t rtable[16] = {
+        0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
+        0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
+        0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
+        0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
+    };
+
+#if 0
+    const uint8_t *data = buffer;
+
+    for (size_t i = 0; i < size; i++) {
+        crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 0)) & 0xf];
+        crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 4)) & 0xf];
+    }
+
+#else
+
+    uint32_t *data_32 = (uint32_t*)buffer;
+
+    for(size_t i = 0; i < (size >> 2); i++, data_32++)
+    {
+        uint32_t aWord = *data_32;
+
+        for(size_t j = 0; j < 4; j++)
+        {
+            crc = (crc >> 4) ^ rtable[(crc ^ ((aWord & 0xff) >> 0)) & 0xf];
+            crc = (crc >> 4) ^ rtable[(crc ^ ((aWord & 0xff) >> 4)) & 0xf];
+            aWord >>= 8;
+        }
+
+    }
+    const uint8_t* data_8 = (uint8_t*)data_32;
+
+    for (size_t i = 0; i < (size & 0x3); i++)
+    {
+        crc = (crc >> 4) ^ rtable[(crc ^ (data_8[i] >> 0)) & 0xf];
+        crc = (crc >> 4) ^ rtable[(crc ^ (data_8[i] >> 4)) & 0xf];
+    }
+
+#endif
+    return crc;
+}
+
+
+#endif