mirror of
https://github.com/littlefs-project/littlefs.git
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a0a55fb9e5
Required to support big-endian processors, with the most notable being the PowerPC architecture. On little-endian architectures, these conversions can be optimized out and have no code impact. Initial patch provided by gmouchard
108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
/*
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* lfs utility functions
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*
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* Copyright (c) 2017 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef LFS_UTIL_H
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#define LFS_UTIL_H
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdio.h>
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// Builtin functions, these may be replaced by more
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// efficient implementations in the system
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static inline uint32_t lfs_max(uint32_t a, uint32_t b) {
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return (a > b) ? a : b;
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}
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static inline uint32_t lfs_min(uint32_t a, uint32_t b) {
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return (a < b) ? a : b;
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}
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static inline uint32_t lfs_npw2(uint32_t a) {
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#if defined(__GNUC__) || defined(__CC_ARM)
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return 32 - __builtin_clz(a-1);
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#else
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uint32_t r = 0;
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uint32_t s;
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a -= 1;
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s = (a > 0xffff) << 4; a >>= s; r |= s;
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s = (a > 0xff ) << 3; a >>= s; r |= s;
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s = (a > 0xf ) << 2; a >>= s; r |= s;
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s = (a > 0x3 ) << 1; a >>= s; r |= s;
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return (r | (a >> 1)) + 1;
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#endif
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}
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static inline uint32_t lfs_ctz(uint32_t a) {
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#if defined(__GNUC__)
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return __builtin_ctz(a);
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#else
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return lfs_npw2((a & -a) + 1) - 1;
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#endif
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}
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static inline uint32_t lfs_popc(uint32_t a) {
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#if defined(__GNUC__) || defined(__CC_ARM)
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return __builtin_popcount(a);
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#else
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a = a - ((a >> 1) & 0x55555555);
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a = (a & 0x33333333) + ((a >> 2) & 0x33333333);
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return (((a + (a >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
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#endif
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}
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static inline int lfs_scmp(uint32_t a, uint32_t b) {
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return (int)(unsigned)(a - b);
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}
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static inline uint32_t lfs_fromle32(uint32_t a) {
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#if ( \
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(defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_LITTLE_ENDIAN ) || \
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(defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_LITTLE_ENDIAN ) || \
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(defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
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return a;
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#elif ( \
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(defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_BIG_ENDIAN ) || \
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(defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_BIG_ENDIAN ) || \
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(defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
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return __builtin_bswap32(a);
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#else
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return (((uint8_t*)&a)[0] << 0) |
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(((uint8_t*)&a)[1] << 8) |
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(((uint8_t*)&a)[2] << 16) |
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(((uint8_t*)&a)[3] << 24);
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#endif
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}
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static inline uint32_t lfs_tole32(uint32_t a) {
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return lfs_fromle32(a);
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}
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// CRC-32 with polynomial = 0x04c11db7
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void lfs_crc(uint32_t *crc, const void *buffer, size_t size);
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// Logging functions, these may be replaced by system-specific
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// logging functions
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#define LFS_DEBUG(fmt, ...) printf("lfs debug: " fmt "\n", __VA_ARGS__)
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#define LFS_WARN(fmt, ...) printf("lfs warn: " fmt "\n", __VA_ARGS__)
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#define LFS_ERROR(fmt, ...) printf("lfs error: " fmt "\n", __VA_ARGS__)
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#endif
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