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| author | Damien George <damien.p.george@gmail.com> | 2019-10-18 17:23:08 +1100 |
|---|---|---|
| committer | Damien George <damien.p.george@gmail.com> | 2019-10-29 12:55:34 +1100 |
| commit | 669d1d20ab8be16bc847d509a9397c2ad4f912fc (patch) | |
| tree | 11d556401f51979f40f243db760c816f65ca6798 /lib/littlefs/lfs1_util.c | |
| parent | e1c7b1cb431f17bc00a76e7d411f5106b1a967cc (diff) | |
| download | micropython-669d1d20ab8be16bc847d509a9397c2ad4f912fc.tar.gz micropython-669d1d20ab8be16bc847d509a9397c2ad4f912fc.zip | |
lib/littlefs: Add littlefs v1.7.2 source.
Diffstat (limited to 'lib/littlefs/lfs1_util.c')
| -rw-r--r-- | lib/littlefs/lfs1_util.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/lib/littlefs/lfs1_util.c b/lib/littlefs/lfs1_util.c new file mode 100644 index 0000000000..3832a5ddb3 --- /dev/null +++ b/lib/littlefs/lfs1_util.c @@ -0,0 +1,31 @@ +/* + * lfs1 util functions + * + * Copyright (c) 2017, Arm Limited. All rights reserved. + * SPDX-License-Identifier: BSD-3-Clause + */ +#include "lfs1_util.h" + +// Only compile if user does not provide custom config +#ifndef LFS1_CONFIG + + +// Software CRC implementation with small lookup table +void lfs1_crc(uint32_t *restrict crc, const void *buffer, size_t size) { + static const uint32_t rtable[16] = { + 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, + 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c, + 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, + 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c, + }; + + 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]; + } +} + + +#endif |