Denislam Valeev
/
Nucleo_rtos_basic
1
mbed-os/drivers/MbedCRC.h@0:e056ac8fecf8, 2018-03-13 (annotated)
- Committer:
- valeyev
- Date:
- Tue Mar 13 07:17:50 2018 +0000
- Revision:
- 0:e056ac8fecf8
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Who changed what in which revision?
User | Revision | Line number | New contents of line |
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valeyev | 0:e056ac8fecf8 | 1 | /* mbed Microcontroller Library |
valeyev | 0:e056ac8fecf8 | 2 | * Copyright (c) 2018 ARM Limited |
valeyev | 0:e056ac8fecf8 | 3 | * |
valeyev | 0:e056ac8fecf8 | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
valeyev | 0:e056ac8fecf8 | 5 | * you may not use this file except in compliance with the License. |
valeyev | 0:e056ac8fecf8 | 6 | * You may obtain a copy of the License at |
valeyev | 0:e056ac8fecf8 | 7 | * |
valeyev | 0:e056ac8fecf8 | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
valeyev | 0:e056ac8fecf8 | 9 | * |
valeyev | 0:e056ac8fecf8 | 10 | * Unless required by applicable law or agreed to in writing, software |
valeyev | 0:e056ac8fecf8 | 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
valeyev | 0:e056ac8fecf8 | 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
valeyev | 0:e056ac8fecf8 | 13 | * See the License for the specific language governing permissions and |
valeyev | 0:e056ac8fecf8 | 14 | * limitations under the License. |
valeyev | 0:e056ac8fecf8 | 15 | */ |
valeyev | 0:e056ac8fecf8 | 16 | #ifndef MBED_CRC_API_H |
valeyev | 0:e056ac8fecf8 | 17 | #define MBED_CRC_API_H |
valeyev | 0:e056ac8fecf8 | 18 | |
valeyev | 0:e056ac8fecf8 | 19 | #include <stdint.h> |
valeyev | 0:e056ac8fecf8 | 20 | #include "drivers/TableCRC.h" |
valeyev | 0:e056ac8fecf8 | 21 | #include "platform/mbed_assert.h" |
valeyev | 0:e056ac8fecf8 | 22 | |
valeyev | 0:e056ac8fecf8 | 23 | /* This is invalid warning from the compiler for below section of code |
valeyev | 0:e056ac8fecf8 | 24 | if ((width < 8) && (NULL == _crc_table)) { |
valeyev | 0:e056ac8fecf8 | 25 | p_crc = (uint32_t)(p_crc << (8 - width)); |
valeyev | 0:e056ac8fecf8 | 26 | } |
valeyev | 0:e056ac8fecf8 | 27 | Compiler warns of the shift operation with width as it is width=(std::uint8_t), |
valeyev | 0:e056ac8fecf8 | 28 | but we check for ( width < 8) before performing shift, so it should not be an issue. |
valeyev | 0:e056ac8fecf8 | 29 | */ |
valeyev | 0:e056ac8fecf8 | 30 | #if defined ( __CC_ARM ) |
valeyev | 0:e056ac8fecf8 | 31 | #pragma diag_suppress 62 // Shift count is negative |
valeyev | 0:e056ac8fecf8 | 32 | #elif defined ( __GNUC__ ) |
valeyev | 0:e056ac8fecf8 | 33 | #pragma GCC diagnostic push |
valeyev | 0:e056ac8fecf8 | 34 | #pragma GCC diagnostic ignored "-Wshift-count-negative" |
valeyev | 0:e056ac8fecf8 | 35 | #endif |
valeyev | 0:e056ac8fecf8 | 36 | |
valeyev | 0:e056ac8fecf8 | 37 | namespace mbed { |
valeyev | 0:e056ac8fecf8 | 38 | /** \addtogroup drivers */ |
valeyev | 0:e056ac8fecf8 | 39 | /** @{*/ |
valeyev | 0:e056ac8fecf8 | 40 | |
valeyev | 0:e056ac8fecf8 | 41 | /** CRC Polynomial value |
valeyev | 0:e056ac8fecf8 | 42 | * |
valeyev | 0:e056ac8fecf8 | 43 | * Different polynomial values supported |
valeyev | 0:e056ac8fecf8 | 44 | */ |
valeyev | 0:e056ac8fecf8 | 45 | typedef enum crc_polynomial { |
valeyev | 0:e056ac8fecf8 | 46 | POLY_OTHER = 0, |
valeyev | 0:e056ac8fecf8 | 47 | POLY_8BIT_CCITT = 0x07, // x8+x2+x+1 |
valeyev | 0:e056ac8fecf8 | 48 | POLY_7BIT_SD = 0x9, // x7+x3+1; |
valeyev | 0:e056ac8fecf8 | 49 | POLY_16BIT_CCITT = 0x1021, // x16+x12+x5+1 |
valeyev | 0:e056ac8fecf8 | 50 | POLY_16BIT_IBM = 0x8005, // x16+x15+x2+1 |
valeyev | 0:e056ac8fecf8 | 51 | POLY_32BIT_ANSI = 0x04C11DB7, // x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1 |
valeyev | 0:e056ac8fecf8 | 52 | } crc_polynomial_t; |
valeyev | 0:e056ac8fecf8 | 53 | |
valeyev | 0:e056ac8fecf8 | 54 | /** CRC object provides CRC generation through hardware/software |
valeyev | 0:e056ac8fecf8 | 55 | * |
valeyev | 0:e056ac8fecf8 | 56 | * ROM polynomial tables for supported polynomials (:: crc_polynomial_t) will be used for |
valeyev | 0:e056ac8fecf8 | 57 | * software CRC computation, if ROM tables are not available then CRC is computed runtime |
valeyev | 0:e056ac8fecf8 | 58 | * bit by bit for all data input. |
valeyev | 0:e056ac8fecf8 | 59 | * |
valeyev | 0:e056ac8fecf8 | 60 | * @tparam polynomial CRC polynomial value in hex |
valeyev | 0:e056ac8fecf8 | 61 | * @tparam width CRC polynomial width |
valeyev | 0:e056ac8fecf8 | 62 | * |
valeyev | 0:e056ac8fecf8 | 63 | * Example: Compute CRC data |
valeyev | 0:e056ac8fecf8 | 64 | * @code |
valeyev | 0:e056ac8fecf8 | 65 | * |
valeyev | 0:e056ac8fecf8 | 66 | * #include "mbed.h" |
valeyev | 0:e056ac8fecf8 | 67 | * |
valeyev | 0:e056ac8fecf8 | 68 | * int main() { |
valeyev | 0:e056ac8fecf8 | 69 | * MbedCRC<POLY_32BIT_ANSI, 32> ct; |
valeyev | 0:e056ac8fecf8 | 70 | * |
valeyev | 0:e056ac8fecf8 | 71 | * char test[] = "123456789"; |
valeyev | 0:e056ac8fecf8 | 72 | * uint32_t crc = 0; |
valeyev | 0:e056ac8fecf8 | 73 | * |
valeyev | 0:e056ac8fecf8 | 74 | * printf("\nPolynomial = 0x%lx Width = %d \n", ct.get_polynomial(), ct.get_width()); |
valeyev | 0:e056ac8fecf8 | 75 | * |
valeyev | 0:e056ac8fecf8 | 76 | * ct.compute((void *)test, strlen((const char*)test), &crc); |
valeyev | 0:e056ac8fecf8 | 77 | * |
valeyev | 0:e056ac8fecf8 | 78 | * printf("The CRC of data \"123456789\" is : 0x%lx\n", crc); |
valeyev | 0:e056ac8fecf8 | 79 | * return 0; |
valeyev | 0:e056ac8fecf8 | 80 | * } |
valeyev | 0:e056ac8fecf8 | 81 | * @endcode |
valeyev | 0:e056ac8fecf8 | 82 | * Example: Compute CRC with data available in parts |
valeyev | 0:e056ac8fecf8 | 83 | * @code |
valeyev | 0:e056ac8fecf8 | 84 | * |
valeyev | 0:e056ac8fecf8 | 85 | * #include "mbed.h" |
valeyev | 0:e056ac8fecf8 | 86 | * int main() { |
valeyev | 0:e056ac8fecf8 | 87 | * MbedCRC<POLY_32BIT_ANSI, 32> ct; |
valeyev | 0:e056ac8fecf8 | 88 | * |
valeyev | 0:e056ac8fecf8 | 89 | * char test[] = "123456789"; |
valeyev | 0:e056ac8fecf8 | 90 | * uint32_t crc = 0; |
valeyev | 0:e056ac8fecf8 | 91 | * |
valeyev | 0:e056ac8fecf8 | 92 | * printf("\nPolynomial = 0x%lx Width = %d \n", ct.get_polynomial(), ct.get_width()); |
valeyev | 0:e056ac8fecf8 | 93 | * |
valeyev | 0:e056ac8fecf8 | 94 | * ct.compute_partial_start(&crc); |
valeyev | 0:e056ac8fecf8 | 95 | * ct.compute_partial((void *)&test, 4, &crc); |
valeyev | 0:e056ac8fecf8 | 96 | * ct.compute_partial((void *)&test[4], 5, &crc); |
valeyev | 0:e056ac8fecf8 | 97 | * ct.compute_partial_stop(&crc); |
valeyev | 0:e056ac8fecf8 | 98 | * |
valeyev | 0:e056ac8fecf8 | 99 | * printf("The CRC of data \"123456789\" is : 0x%lx\n", crc); |
valeyev | 0:e056ac8fecf8 | 100 | * return 0; |
valeyev | 0:e056ac8fecf8 | 101 | * } |
valeyev | 0:e056ac8fecf8 | 102 | * @endcode |
valeyev | 0:e056ac8fecf8 | 103 | * @ingroup drivers |
valeyev | 0:e056ac8fecf8 | 104 | */ |
valeyev | 0:e056ac8fecf8 | 105 | |
valeyev | 0:e056ac8fecf8 | 106 | template <uint32_t polynomial=POLY_32BIT_ANSI, uint8_t width=32> |
valeyev | 0:e056ac8fecf8 | 107 | class MbedCRC |
valeyev | 0:e056ac8fecf8 | 108 | { |
valeyev | 0:e056ac8fecf8 | 109 | public: |
valeyev | 0:e056ac8fecf8 | 110 | typedef uint64_t crc_data_size_t; |
valeyev | 0:e056ac8fecf8 | 111 | |
valeyev | 0:e056ac8fecf8 | 112 | /** Lifetime of CRC object |
valeyev | 0:e056ac8fecf8 | 113 | * |
valeyev | 0:e056ac8fecf8 | 114 | * @param initial_xor Inital value/seed to Xor |
valeyev | 0:e056ac8fecf8 | 115 | * @param final_xor Final Xor value |
valeyev | 0:e056ac8fecf8 | 116 | * @param reflect_data |
valeyev | 0:e056ac8fecf8 | 117 | * @param reflect_remainder |
valeyev | 0:e056ac8fecf8 | 118 | * @note Default constructor without any arguments is valid only for supported CRC polynomials. :: crc_polynomial_t |
valeyev | 0:e056ac8fecf8 | 119 | * MbedCRC <POLY_7BIT_SD, 7> ct; --- Valid POLY_7BIT_SD |
valeyev | 0:e056ac8fecf8 | 120 | * MbedCRC <0x1021, 16> ct; --- Valid POLY_16BIT_CCITT |
valeyev | 0:e056ac8fecf8 | 121 | * MbedCRC <POLY_16BIT_CCITT, 32> ct; --- Invalid, compilation error |
valeyev | 0:e056ac8fecf8 | 122 | * MbedCRC <POLY_16BIT_CCITT, 32> ct (i,f,rd,rr) Consturctor can be used for not supported polynomials |
valeyev | 0:e056ac8fecf8 | 123 | * MbedCRC<POLY_16BIT_CCITT, 16> sd(0, 0, false, false); Constructor can also be used for supported |
valeyev | 0:e056ac8fecf8 | 124 | * polynomials with different intial/final/reflect values |
valeyev | 0:e056ac8fecf8 | 125 | * |
valeyev | 0:e056ac8fecf8 | 126 | */ |
valeyev | 0:e056ac8fecf8 | 127 | MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder); |
valeyev | 0:e056ac8fecf8 | 128 | MbedCRC(); |
valeyev | 0:e056ac8fecf8 | 129 | virtual ~MbedCRC() |
valeyev | 0:e056ac8fecf8 | 130 | { |
valeyev | 0:e056ac8fecf8 | 131 | // Do nothing |
valeyev | 0:e056ac8fecf8 | 132 | } |
valeyev | 0:e056ac8fecf8 | 133 | |
valeyev | 0:e056ac8fecf8 | 134 | /** Compute CRC for the data input |
valeyev | 0:e056ac8fecf8 | 135 | * |
valeyev | 0:e056ac8fecf8 | 136 | * @param buffer Data bytes |
valeyev | 0:e056ac8fecf8 | 137 | * @param size Size of data |
valeyev | 0:e056ac8fecf8 | 138 | * @param crc CRC is the output value |
valeyev | 0:e056ac8fecf8 | 139 | * @return 0 on success, negative error code on failure |
valeyev | 0:e056ac8fecf8 | 140 | */ |
valeyev | 0:e056ac8fecf8 | 141 | int32_t compute(void *buffer, crc_data_size_t size, uint32_t *crc) |
valeyev | 0:e056ac8fecf8 | 142 | { |
valeyev | 0:e056ac8fecf8 | 143 | MBED_ASSERT(crc != NULL); |
valeyev | 0:e056ac8fecf8 | 144 | int32_t status; |
valeyev | 0:e056ac8fecf8 | 145 | if (0 != (status = compute_partial_start(crc))) { |
valeyev | 0:e056ac8fecf8 | 146 | *crc = 0; |
valeyev | 0:e056ac8fecf8 | 147 | return status; |
valeyev | 0:e056ac8fecf8 | 148 | } |
valeyev | 0:e056ac8fecf8 | 149 | if (0 != (status = compute_partial(buffer, size, crc))) { |
valeyev | 0:e056ac8fecf8 | 150 | *crc = 0; |
valeyev | 0:e056ac8fecf8 | 151 | return status; |
valeyev | 0:e056ac8fecf8 | 152 | } |
valeyev | 0:e056ac8fecf8 | 153 | if (0 != (status = compute_partial_stop(crc))) { |
valeyev | 0:e056ac8fecf8 | 154 | *crc = 0; |
valeyev | 0:e056ac8fecf8 | 155 | return status; |
valeyev | 0:e056ac8fecf8 | 156 | } |
valeyev | 0:e056ac8fecf8 | 157 | return 0; |
valeyev | 0:e056ac8fecf8 | 158 | } |
valeyev | 0:e056ac8fecf8 | 159 | |
valeyev | 0:e056ac8fecf8 | 160 | /** Compute partial CRC for the data input. |
valeyev | 0:e056ac8fecf8 | 161 | * |
valeyev | 0:e056ac8fecf8 | 162 | * CRC data if not available fully, CRC can be computed in parts with available data. |
valeyev | 0:e056ac8fecf8 | 163 | * Previous CRC output should be passed as argument to the current compute_partial call. |
valeyev | 0:e056ac8fecf8 | 164 | * @pre: Call \ref compute_partial_start to start the partial CRC calculation. |
valeyev | 0:e056ac8fecf8 | 165 | * @post: Call \ref compute_partial_stop to get the final CRC value. |
valeyev | 0:e056ac8fecf8 | 166 | * |
valeyev | 0:e056ac8fecf8 | 167 | * @param buffer Data bytes |
valeyev | 0:e056ac8fecf8 | 168 | * @param size Size of data |
valeyev | 0:e056ac8fecf8 | 169 | * @param crc CRC value is intermediate CRC value filled by API. |
valeyev | 0:e056ac8fecf8 | 170 | * @return 0 on success or a negative error code on failure |
valeyev | 0:e056ac8fecf8 | 171 | * @note: CRC as output in compute_partial is not final CRC value, call @ref compute_partial_stop |
valeyev | 0:e056ac8fecf8 | 172 | * to get final correct CRC value. |
valeyev | 0:e056ac8fecf8 | 173 | */ |
valeyev | 0:e056ac8fecf8 | 174 | int32_t compute_partial(void *buffer, crc_data_size_t size, uint32_t *crc) |
valeyev | 0:e056ac8fecf8 | 175 | { |
valeyev | 0:e056ac8fecf8 | 176 | if (NULL == _crc_table) { |
valeyev | 0:e056ac8fecf8 | 177 | // Compute bitwise CRC |
valeyev | 0:e056ac8fecf8 | 178 | return bitwise_compute_partial(buffer, size, crc); |
valeyev | 0:e056ac8fecf8 | 179 | } else { |
valeyev | 0:e056ac8fecf8 | 180 | // Table CRC |
valeyev | 0:e056ac8fecf8 | 181 | return table_compute_partial(buffer, size, crc); |
valeyev | 0:e056ac8fecf8 | 182 | } |
valeyev | 0:e056ac8fecf8 | 183 | } |
valeyev | 0:e056ac8fecf8 | 184 | |
valeyev | 0:e056ac8fecf8 | 185 | /** Compute partial start, indicate start of partial computation |
valeyev | 0:e056ac8fecf8 | 186 | * |
valeyev | 0:e056ac8fecf8 | 187 | * This API should be called before performing any partial computation |
valeyev | 0:e056ac8fecf8 | 188 | * with compute_partial API. |
valeyev | 0:e056ac8fecf8 | 189 | * |
valeyev | 0:e056ac8fecf8 | 190 | * @param crc Initial CRC value set by the API |
valeyev | 0:e056ac8fecf8 | 191 | * @return 0 on success or a negative in case of failure |
valeyev | 0:e056ac8fecf8 | 192 | * @note: CRC is an out parameter and must be reused with compute_partial |
valeyev | 0:e056ac8fecf8 | 193 | * and compute_partial_stop without any modifications in application. |
valeyev | 0:e056ac8fecf8 | 194 | */ |
valeyev | 0:e056ac8fecf8 | 195 | int32_t compute_partial_start(uint32_t *crc) |
valeyev | 0:e056ac8fecf8 | 196 | { |
valeyev | 0:e056ac8fecf8 | 197 | MBED_ASSERT(crc != NULL); |
valeyev | 0:e056ac8fecf8 | 198 | *crc = _initial_value; |
valeyev | 0:e056ac8fecf8 | 199 | return 0; |
valeyev | 0:e056ac8fecf8 | 200 | } |
valeyev | 0:e056ac8fecf8 | 201 | |
valeyev | 0:e056ac8fecf8 | 202 | /** Get the final CRC value of partial computation. |
valeyev | 0:e056ac8fecf8 | 203 | * |
valeyev | 0:e056ac8fecf8 | 204 | * CRC value available in partial computation is not correct CRC, as some |
valeyev | 0:e056ac8fecf8 | 205 | * algorithms require remainder to be reflected and final value to be XORed |
valeyev | 0:e056ac8fecf8 | 206 | * This API is used to perform final computation to get correct CRC value. |
valeyev | 0:e056ac8fecf8 | 207 | * |
valeyev | 0:e056ac8fecf8 | 208 | * @param crc CRC result |
valeyev | 0:e056ac8fecf8 | 209 | */ |
valeyev | 0:e056ac8fecf8 | 210 | int32_t compute_partial_stop(uint32_t *crc) |
valeyev | 0:e056ac8fecf8 | 211 | { |
valeyev | 0:e056ac8fecf8 | 212 | MBED_ASSERT(crc != NULL); |
valeyev | 0:e056ac8fecf8 | 213 | uint32_t p_crc = *crc; |
valeyev | 0:e056ac8fecf8 | 214 | if ((width < 8) && (NULL == _crc_table)) { |
valeyev | 0:e056ac8fecf8 | 215 | p_crc = (uint32_t)(p_crc << (8 - width)); |
valeyev | 0:e056ac8fecf8 | 216 | } |
valeyev | 0:e056ac8fecf8 | 217 | *crc = (reflect_remainder(p_crc) ^ _final_xor) & get_crc_mask(); |
valeyev | 0:e056ac8fecf8 | 218 | return 0; |
valeyev | 0:e056ac8fecf8 | 219 | } |
valeyev | 0:e056ac8fecf8 | 220 | |
valeyev | 0:e056ac8fecf8 | 221 | /** Get the current CRC polynomial |
valeyev | 0:e056ac8fecf8 | 222 | * |
valeyev | 0:e056ac8fecf8 | 223 | * @return Polynomial value |
valeyev | 0:e056ac8fecf8 | 224 | */ |
valeyev | 0:e056ac8fecf8 | 225 | uint32_t get_polynomial(void) const |
valeyev | 0:e056ac8fecf8 | 226 | { |
valeyev | 0:e056ac8fecf8 | 227 | return polynomial; |
valeyev | 0:e056ac8fecf8 | 228 | } |
valeyev | 0:e056ac8fecf8 | 229 | |
valeyev | 0:e056ac8fecf8 | 230 | /** Get the current CRC width |
valeyev | 0:e056ac8fecf8 | 231 | * |
valeyev | 0:e056ac8fecf8 | 232 | * @return CRC width |
valeyev | 0:e056ac8fecf8 | 233 | */ |
valeyev | 0:e056ac8fecf8 | 234 | uint8_t get_width(void) const |
valeyev | 0:e056ac8fecf8 | 235 | { |
valeyev | 0:e056ac8fecf8 | 236 | return width; |
valeyev | 0:e056ac8fecf8 | 237 | } |
valeyev | 0:e056ac8fecf8 | 238 | |
valeyev | 0:e056ac8fecf8 | 239 | private: |
valeyev | 0:e056ac8fecf8 | 240 | uint32_t _initial_value; |
valeyev | 0:e056ac8fecf8 | 241 | uint32_t _final_xor; |
valeyev | 0:e056ac8fecf8 | 242 | bool _reflect_data; |
valeyev | 0:e056ac8fecf8 | 243 | bool _reflect_remainder; |
valeyev | 0:e056ac8fecf8 | 244 | uint32_t *_crc_table; |
valeyev | 0:e056ac8fecf8 | 245 | |
valeyev | 0:e056ac8fecf8 | 246 | /** Get the current CRC data size |
valeyev | 0:e056ac8fecf8 | 247 | * |
valeyev | 0:e056ac8fecf8 | 248 | * @return CRC data size in bytes |
valeyev | 0:e056ac8fecf8 | 249 | */ |
valeyev | 0:e056ac8fecf8 | 250 | uint8_t get_data_size(void) const |
valeyev | 0:e056ac8fecf8 | 251 | { |
valeyev | 0:e056ac8fecf8 | 252 | return (width <= 8 ? 1 : (width <= 16 ? 2 : 4)); |
valeyev | 0:e056ac8fecf8 | 253 | } |
valeyev | 0:e056ac8fecf8 | 254 | |
valeyev | 0:e056ac8fecf8 | 255 | /** Get the top bit of current CRC |
valeyev | 0:e056ac8fecf8 | 256 | * |
valeyev | 0:e056ac8fecf8 | 257 | * @return Top bit is set high for respective data width of current CRC |
valeyev | 0:e056ac8fecf8 | 258 | * Top bit for CRC width less then 8 bits will be set as 8th bit. |
valeyev | 0:e056ac8fecf8 | 259 | */ |
valeyev | 0:e056ac8fecf8 | 260 | uint32_t get_top_bit(void) const |
valeyev | 0:e056ac8fecf8 | 261 | { |
valeyev | 0:e056ac8fecf8 | 262 | return (width < 8 ? (1u << 7) : (uint32_t)(1ul << (width - 1))); |
valeyev | 0:e056ac8fecf8 | 263 | } |
valeyev | 0:e056ac8fecf8 | 264 | |
valeyev | 0:e056ac8fecf8 | 265 | /** Get the CRC data mask |
valeyev | 0:e056ac8fecf8 | 266 | * |
valeyev | 0:e056ac8fecf8 | 267 | * @return CRC data mask is generated based on current CRC width |
valeyev | 0:e056ac8fecf8 | 268 | */ |
valeyev | 0:e056ac8fecf8 | 269 | uint32_t get_crc_mask(void) const |
valeyev | 0:e056ac8fecf8 | 270 | { |
valeyev | 0:e056ac8fecf8 | 271 | return (width < 8 ? ((1u << 8) - 1) : (uint32_t)((uint64_t)(1ull << width) - 1)); |
valeyev | 0:e056ac8fecf8 | 272 | } |
valeyev | 0:e056ac8fecf8 | 273 | |
valeyev | 0:e056ac8fecf8 | 274 | /** Final value of CRC is reflected |
valeyev | 0:e056ac8fecf8 | 275 | * |
valeyev | 0:e056ac8fecf8 | 276 | * @param data final crc value, which should be reflected |
valeyev | 0:e056ac8fecf8 | 277 | * @return Reflected CRC value |
valeyev | 0:e056ac8fecf8 | 278 | */ |
valeyev | 0:e056ac8fecf8 | 279 | uint32_t reflect_remainder(uint32_t data) const |
valeyev | 0:e056ac8fecf8 | 280 | { |
valeyev | 0:e056ac8fecf8 | 281 | if (_reflect_remainder) { |
valeyev | 0:e056ac8fecf8 | 282 | uint32_t reflection = 0x0; |
valeyev | 0:e056ac8fecf8 | 283 | uint8_t const nBits = (width < 8 ? 8 : width); |
valeyev | 0:e056ac8fecf8 | 284 | |
valeyev | 0:e056ac8fecf8 | 285 | for (uint8_t bit = 0; bit < nBits; ++bit) { |
valeyev | 0:e056ac8fecf8 | 286 | if (data & 0x01) { |
valeyev | 0:e056ac8fecf8 | 287 | reflection |= (1 << ((nBits - 1) - bit)); |
valeyev | 0:e056ac8fecf8 | 288 | } |
valeyev | 0:e056ac8fecf8 | 289 | data = (data >> 1); |
valeyev | 0:e056ac8fecf8 | 290 | } |
valeyev | 0:e056ac8fecf8 | 291 | return (reflection); |
valeyev | 0:e056ac8fecf8 | 292 | } else { |
valeyev | 0:e056ac8fecf8 | 293 | return data; |
valeyev | 0:e056ac8fecf8 | 294 | } |
valeyev | 0:e056ac8fecf8 | 295 | } |
valeyev | 0:e056ac8fecf8 | 296 | |
valeyev | 0:e056ac8fecf8 | 297 | /** Data bytes are reflected |
valeyev | 0:e056ac8fecf8 | 298 | * |
valeyev | 0:e056ac8fecf8 | 299 | * @param data value to be reflected |
valeyev | 0:e056ac8fecf8 | 300 | * @return Reflected data value |
valeyev | 0:e056ac8fecf8 | 301 | */ |
valeyev | 0:e056ac8fecf8 | 302 | uint32_t reflect_bytes(uint32_t data) const |
valeyev | 0:e056ac8fecf8 | 303 | { |
valeyev | 0:e056ac8fecf8 | 304 | if(_reflect_data) { |
valeyev | 0:e056ac8fecf8 | 305 | uint32_t reflection = 0x0; |
valeyev | 0:e056ac8fecf8 | 306 | |
valeyev | 0:e056ac8fecf8 | 307 | for (uint8_t bit = 0; bit < 8; ++bit) { |
valeyev | 0:e056ac8fecf8 | 308 | if (data & 0x01) { |
valeyev | 0:e056ac8fecf8 | 309 | reflection |= (1 << (7 - bit)); |
valeyev | 0:e056ac8fecf8 | 310 | } |
valeyev | 0:e056ac8fecf8 | 311 | data = (data >> 1); |
valeyev | 0:e056ac8fecf8 | 312 | } |
valeyev | 0:e056ac8fecf8 | 313 | return (reflection); |
valeyev | 0:e056ac8fecf8 | 314 | } else { |
valeyev | 0:e056ac8fecf8 | 315 | return data; |
valeyev | 0:e056ac8fecf8 | 316 | } |
valeyev | 0:e056ac8fecf8 | 317 | } |
valeyev | 0:e056ac8fecf8 | 318 | |
valeyev | 0:e056ac8fecf8 | 319 | /** Bitwise CRC computation |
valeyev | 0:e056ac8fecf8 | 320 | * |
valeyev | 0:e056ac8fecf8 | 321 | * @param buffer data buffer |
valeyev | 0:e056ac8fecf8 | 322 | * @param size size of the data |
valeyev | 0:e056ac8fecf8 | 323 | * @param crc CRC value is filled in, but the value is not the final |
valeyev | 0:e056ac8fecf8 | 324 | * @return 0 on success or a negative error code on failure |
valeyev | 0:e056ac8fecf8 | 325 | */ |
valeyev | 0:e056ac8fecf8 | 326 | int32_t bitwise_compute_partial(const void *buffer, crc_data_size_t size, uint32_t *crc) const |
valeyev | 0:e056ac8fecf8 | 327 | { |
valeyev | 0:e056ac8fecf8 | 328 | MBED_ASSERT(crc != NULL); |
valeyev | 0:e056ac8fecf8 | 329 | MBED_ASSERT(buffer != NULL); |
valeyev | 0:e056ac8fecf8 | 330 | |
valeyev | 0:e056ac8fecf8 | 331 | const uint8_t *data = static_cast<const uint8_t *>(buffer); |
valeyev | 0:e056ac8fecf8 | 332 | uint32_t p_crc = *crc; |
valeyev | 0:e056ac8fecf8 | 333 | |
valeyev | 0:e056ac8fecf8 | 334 | if (width < 8) { |
valeyev | 0:e056ac8fecf8 | 335 | uint8_t data_byte; |
valeyev | 0:e056ac8fecf8 | 336 | for (crc_data_size_t byte = 0; byte < size; byte++) { |
valeyev | 0:e056ac8fecf8 | 337 | data_byte = reflect_bytes(data[byte]); |
valeyev | 0:e056ac8fecf8 | 338 | for (uint8_t bit = 8; bit > 0; --bit) { |
valeyev | 0:e056ac8fecf8 | 339 | p_crc <<= 1; |
valeyev | 0:e056ac8fecf8 | 340 | if (( data_byte ^ p_crc) & get_top_bit()) { |
valeyev | 0:e056ac8fecf8 | 341 | p_crc ^= polynomial; |
valeyev | 0:e056ac8fecf8 | 342 | } |
valeyev | 0:e056ac8fecf8 | 343 | data_byte <<= 1; |
valeyev | 0:e056ac8fecf8 | 344 | } |
valeyev | 0:e056ac8fecf8 | 345 | } |
valeyev | 0:e056ac8fecf8 | 346 | } else { |
valeyev | 0:e056ac8fecf8 | 347 | for (crc_data_size_t byte = 0; byte < size; byte++) { |
valeyev | 0:e056ac8fecf8 | 348 | p_crc ^= (reflect_bytes(data[byte]) << (width - 8)); |
valeyev | 0:e056ac8fecf8 | 349 | |
valeyev | 0:e056ac8fecf8 | 350 | // Perform modulo-2 division, a bit at a time |
valeyev | 0:e056ac8fecf8 | 351 | for (uint8_t bit = 8; bit > 0; --bit) { |
valeyev | 0:e056ac8fecf8 | 352 | if (p_crc & get_top_bit()) { |
valeyev | 0:e056ac8fecf8 | 353 | p_crc = (p_crc << 1) ^ polynomial; |
valeyev | 0:e056ac8fecf8 | 354 | } else { |
valeyev | 0:e056ac8fecf8 | 355 | p_crc = (p_crc << 1); |
valeyev | 0:e056ac8fecf8 | 356 | } |
valeyev | 0:e056ac8fecf8 | 357 | } |
valeyev | 0:e056ac8fecf8 | 358 | } |
valeyev | 0:e056ac8fecf8 | 359 | } |
valeyev | 0:e056ac8fecf8 | 360 | *crc = p_crc & get_crc_mask(); |
valeyev | 0:e056ac8fecf8 | 361 | return 0; |
valeyev | 0:e056ac8fecf8 | 362 | } |
valeyev | 0:e056ac8fecf8 | 363 | |
valeyev | 0:e056ac8fecf8 | 364 | /** CRC computation using ROM tables |
valeyev | 0:e056ac8fecf8 | 365 | * |
valeyev | 0:e056ac8fecf8 | 366 | * @param buffer data buffer |
valeyev | 0:e056ac8fecf8 | 367 | * @param size size of the data |
valeyev | 0:e056ac8fecf8 | 368 | * @param crc CRC value is filled in, but the value is not the final |
valeyev | 0:e056ac8fecf8 | 369 | * @return 0 on success or a negative error code on failure |
valeyev | 0:e056ac8fecf8 | 370 | */ |
valeyev | 0:e056ac8fecf8 | 371 | int32_t table_compute_partial(const void *buffer, crc_data_size_t size, uint32_t *crc) const |
valeyev | 0:e056ac8fecf8 | 372 | { |
valeyev | 0:e056ac8fecf8 | 373 | MBED_ASSERT(crc != NULL); |
valeyev | 0:e056ac8fecf8 | 374 | MBED_ASSERT(buffer != NULL); |
valeyev | 0:e056ac8fecf8 | 375 | |
valeyev | 0:e056ac8fecf8 | 376 | const uint8_t *data = static_cast<const uint8_t *>(buffer); |
valeyev | 0:e056ac8fecf8 | 377 | uint32_t p_crc = *crc; |
valeyev | 0:e056ac8fecf8 | 378 | uint8_t data_byte = 0; |
valeyev | 0:e056ac8fecf8 | 379 | |
valeyev | 0:e056ac8fecf8 | 380 | if (width <= 8) { |
valeyev | 0:e056ac8fecf8 | 381 | uint8_t *crc_table = (uint8_t *)_crc_table; |
valeyev | 0:e056ac8fecf8 | 382 | for (crc_data_size_t byte = 0; byte < size; byte++) { |
valeyev | 0:e056ac8fecf8 | 383 | data_byte = reflect_bytes(data[byte]) ^ p_crc; |
valeyev | 0:e056ac8fecf8 | 384 | p_crc = crc_table[data_byte]; |
valeyev | 0:e056ac8fecf8 | 385 | } |
valeyev | 0:e056ac8fecf8 | 386 | } else if (width <= 16) { |
valeyev | 0:e056ac8fecf8 | 387 | uint16_t *crc_table = (uint16_t *)_crc_table; |
valeyev | 0:e056ac8fecf8 | 388 | for (crc_data_size_t byte = 0; byte < size; byte++) { |
valeyev | 0:e056ac8fecf8 | 389 | data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8)); |
valeyev | 0:e056ac8fecf8 | 390 | p_crc = crc_table[data_byte] ^ (p_crc << 8); |
valeyev | 0:e056ac8fecf8 | 391 | } |
valeyev | 0:e056ac8fecf8 | 392 | } else { |
valeyev | 0:e056ac8fecf8 | 393 | uint32_t *crc_table = (uint32_t *)_crc_table; |
valeyev | 0:e056ac8fecf8 | 394 | for (crc_data_size_t byte = 0; byte < size; byte++) { |
valeyev | 0:e056ac8fecf8 | 395 | data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8)); |
valeyev | 0:e056ac8fecf8 | 396 | p_crc = crc_table[data_byte] ^ (p_crc << 8); |
valeyev | 0:e056ac8fecf8 | 397 | } |
valeyev | 0:e056ac8fecf8 | 398 | } |
valeyev | 0:e056ac8fecf8 | 399 | *crc = p_crc & get_crc_mask(); |
valeyev | 0:e056ac8fecf8 | 400 | return 0; |
valeyev | 0:e056ac8fecf8 | 401 | } |
valeyev | 0:e056ac8fecf8 | 402 | |
valeyev | 0:e056ac8fecf8 | 403 | /** Constructor init called from all specialized cases of constructor |
valeyev | 0:e056ac8fecf8 | 404 | * Note: All construtor common code should be in this function. |
valeyev | 0:e056ac8fecf8 | 405 | */ |
valeyev | 0:e056ac8fecf8 | 406 | void mbed_crc_ctor(void) const |
valeyev | 0:e056ac8fecf8 | 407 | { |
valeyev | 0:e056ac8fecf8 | 408 | MBED_STATIC_ASSERT(width <= 32, "Max 32-bit CRC supported"); |
valeyev | 0:e056ac8fecf8 | 409 | } |
valeyev | 0:e056ac8fecf8 | 410 | }; |
valeyev | 0:e056ac8fecf8 | 411 | |
valeyev | 0:e056ac8fecf8 | 412 | #if defined ( __CC_ARM ) |
valeyev | 0:e056ac8fecf8 | 413 | #elif defined ( __GNUC__ ) |
valeyev | 0:e056ac8fecf8 | 414 | #pragma GCC diagnostic pop |
valeyev | 0:e056ac8fecf8 | 415 | #endif |
valeyev | 0:e056ac8fecf8 | 416 | |
valeyev | 0:e056ac8fecf8 | 417 | /** @}*/ |
valeyev | 0:e056ac8fecf8 | 418 | } // namespace mbed |
valeyev | 0:e056ac8fecf8 | 419 | |
valeyev | 0:e056ac8fecf8 | 420 | #endif |