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mbed 2

This is the mbed 2 library. If you'd like to learn about Mbed OS please see the mbed-os docs.

drivers/MbedCRC.h@169:a7c7b631e539, 2018-06-22 (annotated)

Committer:
Anna Bridge
Date:
Fri Jun 22 15:38:59 2018 +0100
Revision:
169:a7c7b631e539
Parent:
165:d1b4690b3f8b
Child:
170:e95d10626187
mbed library. Release version 162

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AnnaBridge 165:d1b4690b3f8b 1 /* mbed Microcontroller Library
AnnaBridge 165:d1b4690b3f8b 2 * Copyright (c) 2018 ARM Limited
AnnaBridge 165:d1b4690b3f8b 3 *
AnnaBridge 165:d1b4690b3f8b 4 * Licensed under the Apache License, Version 2.0 (the "License");
AnnaBridge 165:d1b4690b3f8b 5 * you may not use this file except in compliance with the License.
AnnaBridge 165:d1b4690b3f8b 6 * You may obtain a copy of the License at
AnnaBridge 165:d1b4690b3f8b 7 *
AnnaBridge 165:d1b4690b3f8b 8 * http://www.apache.org/licenses/LICENSE-2.0
AnnaBridge 165:d1b4690b3f8b 9 *
AnnaBridge 165:d1b4690b3f8b 10 * Unless required by applicable law or agreed to in writing, software
AnnaBridge 165:d1b4690b3f8b 11 * distributed under the License is distributed on an "AS IS" BASIS,
AnnaBridge 165:d1b4690b3f8b 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
AnnaBridge 165:d1b4690b3f8b 13 * See the License for the specific language governing permissions and
AnnaBridge 165:d1b4690b3f8b 14 * limitations under the License.
AnnaBridge 165:d1b4690b3f8b 15 */
AnnaBridge 165:d1b4690b3f8b 16 #ifndef MBED_CRC_API_H
AnnaBridge 165:d1b4690b3f8b 17 #define MBED_CRC_API_H
AnnaBridge 165:d1b4690b3f8b 18
AnnaBridge 165:d1b4690b3f8b 19 #include "drivers/TableCRC.h"
Anna Bridge 169:a7c7b631e539 20 #include "hal/crc_api.h"
AnnaBridge 165:d1b4690b3f8b 21 #include "platform/mbed_assert.h"
AnnaBridge 165:d1b4690b3f8b 22
AnnaBridge 165:d1b4690b3f8b 23 /* This is invalid warning from the compiler for below section of code
AnnaBridge 165:d1b4690b3f8b 24 if ((width < 8) && (NULL == _crc_table)) {
AnnaBridge 165:d1b4690b3f8b 25 p_crc = (uint32_t)(p_crc << (8 - width));
AnnaBridge 165:d1b4690b3f8b 26 }
AnnaBridge 165:d1b4690b3f8b 27 Compiler warns of the shift operation with width as it is width=(std::uint8_t),
AnnaBridge 165:d1b4690b3f8b 28 but we check for ( width < 8) before performing shift, so it should not be an issue.
AnnaBridge 165:d1b4690b3f8b 29 */
AnnaBridge 165:d1b4690b3f8b 30 #if defined ( __CC_ARM )
AnnaBridge 165:d1b4690b3f8b 31 #pragma diag_suppress 62 // Shift count is negative
AnnaBridge 165:d1b4690b3f8b 32 #elif defined ( __GNUC__ )
AnnaBridge 165:d1b4690b3f8b 33 #pragma GCC diagnostic push
AnnaBridge 165:d1b4690b3f8b 34 #pragma GCC diagnostic ignored "-Wshift-count-negative"
AnnaBridge 165:d1b4690b3f8b 35 #endif
AnnaBridge 165:d1b4690b3f8b 36
AnnaBridge 165:d1b4690b3f8b 37 namespace mbed {
AnnaBridge 165:d1b4690b3f8b 38 /** \addtogroup drivers */
AnnaBridge 165:d1b4690b3f8b 39 /** @{*/
AnnaBridge 165:d1b4690b3f8b 40
AnnaBridge 165:d1b4690b3f8b 41 /** CRC object provides CRC generation through hardware/software
AnnaBridge 165:d1b4690b3f8b 42 *
AnnaBridge 165:d1b4690b3f8b 43 * ROM polynomial tables for supported polynomials (:: crc_polynomial_t) will be used for
AnnaBridge 165:d1b4690b3f8b 44 * software CRC computation, if ROM tables are not available then CRC is computed runtime
AnnaBridge 165:d1b4690b3f8b 45 * bit by bit for all data input.
AnnaBridge 165:d1b4690b3f8b 46 *
AnnaBridge 165:d1b4690b3f8b 47 * @tparam polynomial CRC polynomial value in hex
AnnaBridge 165:d1b4690b3f8b 48 * @tparam width CRC polynomial width
AnnaBridge 165:d1b4690b3f8b 49 *
AnnaBridge 165:d1b4690b3f8b 50 * Example: Compute CRC data
AnnaBridge 165:d1b4690b3f8b 51 * @code
AnnaBridge 165:d1b4690b3f8b 52 *
AnnaBridge 165:d1b4690b3f8b 53 * #include "mbed.h"
AnnaBridge 165:d1b4690b3f8b 54 *
AnnaBridge 165:d1b4690b3f8b 55 * int main() {
AnnaBridge 165:d1b4690b3f8b 56 * MbedCRC<POLY_32BIT_ANSI, 32> ct;
AnnaBridge 165:d1b4690b3f8b 57 *
AnnaBridge 165:d1b4690b3f8b 58 * char test[] = "123456789";
AnnaBridge 165:d1b4690b3f8b 59 * uint32_t crc = 0;
AnnaBridge 165:d1b4690b3f8b 60 *
AnnaBridge 165:d1b4690b3f8b 61 * printf("\nPolynomial = 0x%lx Width = %d \n", ct.get_polynomial(), ct.get_width());
AnnaBridge 165:d1b4690b3f8b 62 *
AnnaBridge 165:d1b4690b3f8b 63 * ct.compute((void *)test, strlen((const char*)test), &crc);
AnnaBridge 165:d1b4690b3f8b 64 *
AnnaBridge 165:d1b4690b3f8b 65 * printf("The CRC of data \"123456789\" is : 0x%lx\n", crc);
AnnaBridge 165:d1b4690b3f8b 66 * return 0;
AnnaBridge 165:d1b4690b3f8b 67 * }
AnnaBridge 165:d1b4690b3f8b 68 * @endcode
AnnaBridge 165:d1b4690b3f8b 69 * Example: Compute CRC with data available in parts
AnnaBridge 165:d1b4690b3f8b 70 * @code
AnnaBridge 165:d1b4690b3f8b 71 *
AnnaBridge 165:d1b4690b3f8b 72 * #include "mbed.h"
AnnaBridge 165:d1b4690b3f8b 73 * int main() {
AnnaBridge 165:d1b4690b3f8b 74 * MbedCRC<POLY_32BIT_ANSI, 32> ct;
AnnaBridge 165:d1b4690b3f8b 75 *
AnnaBridge 165:d1b4690b3f8b 76 * char test[] = "123456789";
AnnaBridge 165:d1b4690b3f8b 77 * uint32_t crc = 0;
AnnaBridge 165:d1b4690b3f8b 78 *
AnnaBridge 165:d1b4690b3f8b 79 * printf("\nPolynomial = 0x%lx Width = %d \n", ct.get_polynomial(), ct.get_width());
AnnaBridge 165:d1b4690b3f8b 80 *
AnnaBridge 165:d1b4690b3f8b 81 * ct.compute_partial_start(&crc);
AnnaBridge 165:d1b4690b3f8b 82 * ct.compute_partial((void *)&test, 4, &crc);
AnnaBridge 165:d1b4690b3f8b 83 * ct.compute_partial((void *)&test[4], 5, &crc);
AnnaBridge 165:d1b4690b3f8b 84 * ct.compute_partial_stop(&crc);
AnnaBridge 165:d1b4690b3f8b 85 *
AnnaBridge 165:d1b4690b3f8b 86 * printf("The CRC of data \"123456789\" is : 0x%lx\n", crc);
AnnaBridge 165:d1b4690b3f8b 87 * return 0;
AnnaBridge 165:d1b4690b3f8b 88 * }
AnnaBridge 165:d1b4690b3f8b 89 * @endcode
AnnaBridge 165:d1b4690b3f8b 90 * @ingroup drivers
AnnaBridge 165:d1b4690b3f8b 91 */
AnnaBridge 165:d1b4690b3f8b 92
AnnaBridge 165:d1b4690b3f8b 93 template <uint32_t polynomial=POLY_32BIT_ANSI, uint8_t width=32>
AnnaBridge 165:d1b4690b3f8b 94 class MbedCRC
AnnaBridge 165:d1b4690b3f8b 95 {
AnnaBridge 165:d1b4690b3f8b 96 public:
Anna Bridge 169:a7c7b631e539 97 enum CrcMode { HARDWARE = 0, TABLE, BITWISE };
Anna Bridge 169:a7c7b631e539 98
Anna Bridge 169:a7c7b631e539 99 public:
AnnaBridge 165:d1b4690b3f8b 100 typedef uint64_t crc_data_size_t;
AnnaBridge 165:d1b4690b3f8b 101
AnnaBridge 165:d1b4690b3f8b 102 /** Lifetime of CRC object
AnnaBridge 165:d1b4690b3f8b 103 *
AnnaBridge 165:d1b4690b3f8b 104 * @param initial_xor Inital value/seed to Xor
AnnaBridge 165:d1b4690b3f8b 105 * @param final_xor Final Xor value
AnnaBridge 165:d1b4690b3f8b 106 * @param reflect_data
AnnaBridge 165:d1b4690b3f8b 107 * @param reflect_remainder
AnnaBridge 165:d1b4690b3f8b 108 * @note Default constructor without any arguments is valid only for supported CRC polynomials. :: crc_polynomial_t
AnnaBridge 165:d1b4690b3f8b 109 * MbedCRC <POLY_7BIT_SD, 7> ct; --- Valid POLY_7BIT_SD
AnnaBridge 165:d1b4690b3f8b 110 * MbedCRC <0x1021, 16> ct; --- Valid POLY_16BIT_CCITT
AnnaBridge 165:d1b4690b3f8b 111 * MbedCRC <POLY_16BIT_CCITT, 32> ct; --- Invalid, compilation error
AnnaBridge 165:d1b4690b3f8b 112 * MbedCRC <POLY_16BIT_CCITT, 32> ct (i,f,rd,rr) Consturctor can be used for not supported polynomials
AnnaBridge 165:d1b4690b3f8b 113 * MbedCRC<POLY_16BIT_CCITT, 16> sd(0, 0, false, false); Constructor can also be used for supported
AnnaBridge 165:d1b4690b3f8b 114 * polynomials with different intial/final/reflect values
AnnaBridge 165:d1b4690b3f8b 115 *
AnnaBridge 165:d1b4690b3f8b 116 */
AnnaBridge 165:d1b4690b3f8b 117 MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder) :
AnnaBridge 165:d1b4690b3f8b 118 _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data),
AnnaBridge 165:d1b4690b3f8b 119 _reflect_remainder(reflect_remainder), _crc_table(NULL)
AnnaBridge 165:d1b4690b3f8b 120 {
AnnaBridge 165:d1b4690b3f8b 121 mbed_crc_ctor();
AnnaBridge 165:d1b4690b3f8b 122 }
AnnaBridge 165:d1b4690b3f8b 123 MbedCRC();
AnnaBridge 165:d1b4690b3f8b 124 virtual ~MbedCRC()
AnnaBridge 165:d1b4690b3f8b 125 {
AnnaBridge 165:d1b4690b3f8b 126 // Do nothing
AnnaBridge 165:d1b4690b3f8b 127 }
AnnaBridge 165:d1b4690b3f8b 128
AnnaBridge 165:d1b4690b3f8b 129 /** Compute CRC for the data input
AnnaBridge 165:d1b4690b3f8b 130 *
AnnaBridge 165:d1b4690b3f8b 131 * @param buffer Data bytes
AnnaBridge 165:d1b4690b3f8b 132 * @param size Size of data
AnnaBridge 165:d1b4690b3f8b 133 * @param crc CRC is the output value
AnnaBridge 165:d1b4690b3f8b 134 * @return 0 on success, negative error code on failure
AnnaBridge 165:d1b4690b3f8b 135 */
AnnaBridge 165:d1b4690b3f8b 136 int32_t compute(void *buffer, crc_data_size_t size, uint32_t *crc)
AnnaBridge 165:d1b4690b3f8b 137 {
AnnaBridge 165:d1b4690b3f8b 138 MBED_ASSERT(crc != NULL);
AnnaBridge 165:d1b4690b3f8b 139 int32_t status;
AnnaBridge 165:d1b4690b3f8b 140 if (0 != (status = compute_partial_start(crc))) {
AnnaBridge 165:d1b4690b3f8b 141 *crc = 0;
AnnaBridge 165:d1b4690b3f8b 142 return status;
AnnaBridge 165:d1b4690b3f8b 143 }
AnnaBridge 165:d1b4690b3f8b 144 if (0 != (status = compute_partial(buffer, size, crc))) {
AnnaBridge 165:d1b4690b3f8b 145 *crc = 0;
AnnaBridge 165:d1b4690b3f8b 146 return status;
AnnaBridge 165:d1b4690b3f8b 147 }
AnnaBridge 165:d1b4690b3f8b 148 if (0 != (status = compute_partial_stop(crc))) {
AnnaBridge 165:d1b4690b3f8b 149 *crc = 0;
AnnaBridge 165:d1b4690b3f8b 150 return status;
AnnaBridge 165:d1b4690b3f8b 151 }
AnnaBridge 165:d1b4690b3f8b 152 return 0;
AnnaBridge 165:d1b4690b3f8b 153 }
AnnaBridge 165:d1b4690b3f8b 154
AnnaBridge 165:d1b4690b3f8b 155 /** Compute partial CRC for the data input.
AnnaBridge 165:d1b4690b3f8b 156 *
AnnaBridge 165:d1b4690b3f8b 157 * CRC data if not available fully, CRC can be computed in parts with available data.
AnnaBridge 165:d1b4690b3f8b 158 * Previous CRC output should be passed as argument to the current compute_partial call.
AnnaBridge 165:d1b4690b3f8b 159 * @pre: Call \ref compute_partial_start to start the partial CRC calculation.
AnnaBridge 165:d1b4690b3f8b 160 * @post: Call \ref compute_partial_stop to get the final CRC value.
AnnaBridge 165:d1b4690b3f8b 161 *
AnnaBridge 165:d1b4690b3f8b 162 * @param buffer Data bytes
AnnaBridge 165:d1b4690b3f8b 163 * @param size Size of data
AnnaBridge 165:d1b4690b3f8b 164 * @param crc CRC value is intermediate CRC value filled by API.
AnnaBridge 165:d1b4690b3f8b 165 * @return 0 on success or a negative error code on failure
AnnaBridge 165:d1b4690b3f8b 166 * @note: CRC as output in compute_partial is not final CRC value, call @ref compute_partial_stop
AnnaBridge 165:d1b4690b3f8b 167 * to get final correct CRC value.
AnnaBridge 165:d1b4690b3f8b 168 */
AnnaBridge 165:d1b4690b3f8b 169 int32_t compute_partial(void *buffer, crc_data_size_t size, uint32_t *crc)
AnnaBridge 165:d1b4690b3f8b 170 {
Anna Bridge 169:a7c7b631e539 171 switch (_mode)
Anna Bridge 169:a7c7b631e539 172 {
Anna Bridge 169:a7c7b631e539 173 case HARDWARE:
Anna Bridge 169:a7c7b631e539 174 #ifdef DEVICE_CRC
Anna Bridge 169:a7c7b631e539 175 hal_crc_compute_partial((uint8_t *)buffer, size);
Anna Bridge 169:a7c7b631e539 176 #endif // DEVICE_CRC
Anna Bridge 169:a7c7b631e539 177 *crc = 0;
Anna Bridge 169:a7c7b631e539 178 return 0;
Anna Bridge 169:a7c7b631e539 179 case TABLE:
Anna Bridge 169:a7c7b631e539 180 return table_compute_partial(buffer, size, crc);
Anna Bridge 169:a7c7b631e539 181 case BITWISE:
Anna Bridge 169:a7c7b631e539 182 return bitwise_compute_partial(buffer, size, crc);
AnnaBridge 165:d1b4690b3f8b 183 }
Anna Bridge 169:a7c7b631e539 184
Anna Bridge 169:a7c7b631e539 185 return -1;
AnnaBridge 165:d1b4690b3f8b 186 }
AnnaBridge 165:d1b4690b3f8b 187
AnnaBridge 165:d1b4690b3f8b 188 /** Compute partial start, indicate start of partial computation
AnnaBridge 165:d1b4690b3f8b 189 *
AnnaBridge 165:d1b4690b3f8b 190 * This API should be called before performing any partial computation
AnnaBridge 165:d1b4690b3f8b 191 * with compute_partial API.
AnnaBridge 165:d1b4690b3f8b 192 *
AnnaBridge 165:d1b4690b3f8b 193 * @param crc Initial CRC value set by the API
AnnaBridge 165:d1b4690b3f8b 194 * @return 0 on success or a negative in case of failure
AnnaBridge 165:d1b4690b3f8b 195 * @note: CRC is an out parameter and must be reused with compute_partial
AnnaBridge 165:d1b4690b3f8b 196 * and compute_partial_stop without any modifications in application.
AnnaBridge 165:d1b4690b3f8b 197 */
AnnaBridge 165:d1b4690b3f8b 198 int32_t compute_partial_start(uint32_t *crc)
AnnaBridge 165:d1b4690b3f8b 199 {
AnnaBridge 165:d1b4690b3f8b 200 MBED_ASSERT(crc != NULL);
Anna Bridge 169:a7c7b631e539 201
Anna Bridge 169:a7c7b631e539 202 #ifdef DEVICE_CRC
Anna Bridge 169:a7c7b631e539 203 if (_mode == HARDWARE) {
Anna Bridge 169:a7c7b631e539 204 crc_mbed_config_t config;
Anna Bridge 169:a7c7b631e539 205 config.polynomial = polynomial;
Anna Bridge 169:a7c7b631e539 206 config.width = width;
Anna Bridge 169:a7c7b631e539 207 config.initial_xor = _initial_value;
Anna Bridge 169:a7c7b631e539 208 config.final_xor = _final_xor;
Anna Bridge 169:a7c7b631e539 209 config.reflect_in = _reflect_data;
Anna Bridge 169:a7c7b631e539 210 config.reflect_out = _reflect_remainder;
Anna Bridge 169:a7c7b631e539 211
Anna Bridge 169:a7c7b631e539 212 hal_crc_compute_partial_start(&config);
Anna Bridge 169:a7c7b631e539 213 }
Anna Bridge 169:a7c7b631e539 214 #endif // DEVICE_CRC
Anna Bridge 169:a7c7b631e539 215
AnnaBridge 165:d1b4690b3f8b 216 *crc = _initial_value;
AnnaBridge 165:d1b4690b3f8b 217 return 0;
AnnaBridge 165:d1b4690b3f8b 218 }
AnnaBridge 165:d1b4690b3f8b 219
AnnaBridge 165:d1b4690b3f8b 220 /** Get the final CRC value of partial computation.
AnnaBridge 165:d1b4690b3f8b 221 *
AnnaBridge 165:d1b4690b3f8b 222 * CRC value available in partial computation is not correct CRC, as some
AnnaBridge 165:d1b4690b3f8b 223 * algorithms require remainder to be reflected and final value to be XORed
AnnaBridge 165:d1b4690b3f8b 224 * This API is used to perform final computation to get correct CRC value.
AnnaBridge 165:d1b4690b3f8b 225 *
AnnaBridge 165:d1b4690b3f8b 226 * @param crc CRC result
AnnaBridge 165:d1b4690b3f8b 227 */
AnnaBridge 165:d1b4690b3f8b 228 int32_t compute_partial_stop(uint32_t *crc)
AnnaBridge 165:d1b4690b3f8b 229 {
AnnaBridge 165:d1b4690b3f8b 230 MBED_ASSERT(crc != NULL);
Anna Bridge 169:a7c7b631e539 231
Anna Bridge 169:a7c7b631e539 232 if (_mode == HARDWARE) {
Anna Bridge 169:a7c7b631e539 233 #ifdef DEVICE_CRC
Anna Bridge 169:a7c7b631e539 234 *crc = hal_crc_get_result();
Anna Bridge 169:a7c7b631e539 235 return 0;
Anna Bridge 169:a7c7b631e539 236 #else
Anna Bridge 169:a7c7b631e539 237 return -1;
Anna Bridge 169:a7c7b631e539 238 #endif
Anna Bridge 169:a7c7b631e539 239 }
Anna Bridge 169:a7c7b631e539 240
AnnaBridge 165:d1b4690b3f8b 241 uint32_t p_crc = *crc;
AnnaBridge 165:d1b4690b3f8b 242 if ((width < 8) && (NULL == _crc_table)) {
AnnaBridge 165:d1b4690b3f8b 243 p_crc = (uint32_t)(p_crc << (8 - width));
AnnaBridge 165:d1b4690b3f8b 244 }
AnnaBridge 165:d1b4690b3f8b 245 *crc = (reflect_remainder(p_crc) ^ _final_xor) & get_crc_mask();
AnnaBridge 165:d1b4690b3f8b 246 return 0;
AnnaBridge 165:d1b4690b3f8b 247 }
AnnaBridge 165:d1b4690b3f8b 248
AnnaBridge 165:d1b4690b3f8b 249 /** Get the current CRC polynomial
AnnaBridge 165:d1b4690b3f8b 250 *
AnnaBridge 165:d1b4690b3f8b 251 * @return Polynomial value
AnnaBridge 165:d1b4690b3f8b 252 */
AnnaBridge 165:d1b4690b3f8b 253 uint32_t get_polynomial(void) const
AnnaBridge 165:d1b4690b3f8b 254 {
AnnaBridge 165:d1b4690b3f8b 255 return polynomial;
AnnaBridge 165:d1b4690b3f8b 256 }
AnnaBridge 165:d1b4690b3f8b 257
AnnaBridge 165:d1b4690b3f8b 258 /** Get the current CRC width
AnnaBridge 165:d1b4690b3f8b 259 *
AnnaBridge 165:d1b4690b3f8b 260 * @return CRC width
AnnaBridge 165:d1b4690b3f8b 261 */
AnnaBridge 165:d1b4690b3f8b 262 uint8_t get_width(void) const
AnnaBridge 165:d1b4690b3f8b 263 {
AnnaBridge 165:d1b4690b3f8b 264 return width;
AnnaBridge 165:d1b4690b3f8b 265 }
AnnaBridge 165:d1b4690b3f8b 266
AnnaBridge 165:d1b4690b3f8b 267 private:
AnnaBridge 165:d1b4690b3f8b 268 uint32_t _initial_value;
AnnaBridge 165:d1b4690b3f8b 269 uint32_t _final_xor;
AnnaBridge 165:d1b4690b3f8b 270 bool _reflect_data;
AnnaBridge 165:d1b4690b3f8b 271 bool _reflect_remainder;
AnnaBridge 165:d1b4690b3f8b 272 uint32_t *_crc_table;
Anna Bridge 169:a7c7b631e539 273 CrcMode _mode;
AnnaBridge 165:d1b4690b3f8b 274
AnnaBridge 165:d1b4690b3f8b 275 /** Get the current CRC data size
AnnaBridge 165:d1b4690b3f8b 276 *
AnnaBridge 165:d1b4690b3f8b 277 * @return CRC data size in bytes
AnnaBridge 165:d1b4690b3f8b 278 */
AnnaBridge 165:d1b4690b3f8b 279 uint8_t get_data_size(void) const
AnnaBridge 165:d1b4690b3f8b 280 {
AnnaBridge 165:d1b4690b3f8b 281 return (width <= 8 ? 1 : (width <= 16 ? 2 : 4));
AnnaBridge 165:d1b4690b3f8b 282 }
AnnaBridge 165:d1b4690b3f8b 283
AnnaBridge 165:d1b4690b3f8b 284 /** Get the top bit of current CRC
AnnaBridge 165:d1b4690b3f8b 285 *
AnnaBridge 165:d1b4690b3f8b 286 * @return Top bit is set high for respective data width of current CRC
AnnaBridge 165:d1b4690b3f8b 287 * Top bit for CRC width less then 8 bits will be set as 8th bit.
AnnaBridge 165:d1b4690b3f8b 288 */
AnnaBridge 165:d1b4690b3f8b 289 uint32_t get_top_bit(void) const
AnnaBridge 165:d1b4690b3f8b 290 {
AnnaBridge 165:d1b4690b3f8b 291 return (width < 8 ? (1u << 7) : (uint32_t)(1ul << (width - 1)));
AnnaBridge 165:d1b4690b3f8b 292 }
AnnaBridge 165:d1b4690b3f8b 293
AnnaBridge 165:d1b4690b3f8b 294 /** Get the CRC data mask
AnnaBridge 165:d1b4690b3f8b 295 *
AnnaBridge 165:d1b4690b3f8b 296 * @return CRC data mask is generated based on current CRC width
AnnaBridge 165:d1b4690b3f8b 297 */
AnnaBridge 165:d1b4690b3f8b 298 uint32_t get_crc_mask(void) const
AnnaBridge 165:d1b4690b3f8b 299 {
AnnaBridge 165:d1b4690b3f8b 300 return (width < 8 ? ((1u << 8) - 1) : (uint32_t)((uint64_t)(1ull << width) - 1));
AnnaBridge 165:d1b4690b3f8b 301 }
AnnaBridge 165:d1b4690b3f8b 302
AnnaBridge 165:d1b4690b3f8b 303 /** Final value of CRC is reflected
AnnaBridge 165:d1b4690b3f8b 304 *
AnnaBridge 165:d1b4690b3f8b 305 * @param data final crc value, which should be reflected
AnnaBridge 165:d1b4690b3f8b 306 * @return Reflected CRC value
AnnaBridge 165:d1b4690b3f8b 307 */
AnnaBridge 165:d1b4690b3f8b 308 uint32_t reflect_remainder(uint32_t data) const
AnnaBridge 165:d1b4690b3f8b 309 {
AnnaBridge 165:d1b4690b3f8b 310 if (_reflect_remainder) {
AnnaBridge 165:d1b4690b3f8b 311 uint32_t reflection = 0x0;
AnnaBridge 165:d1b4690b3f8b 312 uint8_t const nBits = (width < 8 ? 8 : width);
AnnaBridge 165:d1b4690b3f8b 313
AnnaBridge 165:d1b4690b3f8b 314 for (uint8_t bit = 0; bit < nBits; ++bit) {
AnnaBridge 165:d1b4690b3f8b 315 if (data & 0x01) {
AnnaBridge 165:d1b4690b3f8b 316 reflection |= (1 << ((nBits - 1) - bit));
AnnaBridge 165:d1b4690b3f8b 317 }
AnnaBridge 165:d1b4690b3f8b 318 data = (data >> 1);
AnnaBridge 165:d1b4690b3f8b 319 }
AnnaBridge 165:d1b4690b3f8b 320 return (reflection);
AnnaBridge 165:d1b4690b3f8b 321 } else {
AnnaBridge 165:d1b4690b3f8b 322 return data;
AnnaBridge 165:d1b4690b3f8b 323 }
AnnaBridge 165:d1b4690b3f8b 324 }
AnnaBridge 165:d1b4690b3f8b 325
AnnaBridge 165:d1b4690b3f8b 326 /** Data bytes are reflected
AnnaBridge 165:d1b4690b3f8b 327 *
AnnaBridge 165:d1b4690b3f8b 328 * @param data value to be reflected
AnnaBridge 165:d1b4690b3f8b 329 * @return Reflected data value
AnnaBridge 165:d1b4690b3f8b 330 */
AnnaBridge 165:d1b4690b3f8b 331 uint32_t reflect_bytes(uint32_t data) const
AnnaBridge 165:d1b4690b3f8b 332 {
AnnaBridge 165:d1b4690b3f8b 333 if(_reflect_data) {
AnnaBridge 165:d1b4690b3f8b 334 uint32_t reflection = 0x0;
AnnaBridge 165:d1b4690b3f8b 335
AnnaBridge 165:d1b4690b3f8b 336 for (uint8_t bit = 0; bit < 8; ++bit) {
AnnaBridge 165:d1b4690b3f8b 337 if (data & 0x01) {
AnnaBridge 165:d1b4690b3f8b 338 reflection |= (1 << (7 - bit));
AnnaBridge 165:d1b4690b3f8b 339 }
AnnaBridge 165:d1b4690b3f8b 340 data = (data >> 1);
AnnaBridge 165:d1b4690b3f8b 341 }
AnnaBridge 165:d1b4690b3f8b 342 return (reflection);
AnnaBridge 165:d1b4690b3f8b 343 } else {
AnnaBridge 165:d1b4690b3f8b 344 return data;
AnnaBridge 165:d1b4690b3f8b 345 }
AnnaBridge 165:d1b4690b3f8b 346 }
AnnaBridge 165:d1b4690b3f8b 347
AnnaBridge 165:d1b4690b3f8b 348 /** Bitwise CRC computation
AnnaBridge 165:d1b4690b3f8b 349 *
AnnaBridge 165:d1b4690b3f8b 350 * @param buffer data buffer
AnnaBridge 165:d1b4690b3f8b 351 * @param size size of the data
AnnaBridge 165:d1b4690b3f8b 352 * @param crc CRC value is filled in, but the value is not the final
AnnaBridge 165:d1b4690b3f8b 353 * @return 0 on success or a negative error code on failure
AnnaBridge 165:d1b4690b3f8b 354 */
AnnaBridge 165:d1b4690b3f8b 355 int32_t bitwise_compute_partial(const void *buffer, crc_data_size_t size, uint32_t *crc) const
AnnaBridge 165:d1b4690b3f8b 356 {
AnnaBridge 165:d1b4690b3f8b 357 MBED_ASSERT(crc != NULL);
AnnaBridge 165:d1b4690b3f8b 358 MBED_ASSERT(buffer != NULL);
AnnaBridge 165:d1b4690b3f8b 359
AnnaBridge 165:d1b4690b3f8b 360 const uint8_t *data = static_cast<const uint8_t *>(buffer);
AnnaBridge 165:d1b4690b3f8b 361 uint32_t p_crc = *crc;
AnnaBridge 165:d1b4690b3f8b 362
AnnaBridge 165:d1b4690b3f8b 363 if (width < 8) {
AnnaBridge 165:d1b4690b3f8b 364 uint8_t data_byte;
AnnaBridge 165:d1b4690b3f8b 365 for (crc_data_size_t byte = 0; byte < size; byte++) {
AnnaBridge 165:d1b4690b3f8b 366 data_byte = reflect_bytes(data[byte]);
AnnaBridge 165:d1b4690b3f8b 367 for (uint8_t bit = 8; bit > 0; --bit) {
AnnaBridge 165:d1b4690b3f8b 368 p_crc <<= 1;
AnnaBridge 165:d1b4690b3f8b 369 if (( data_byte ^ p_crc) & get_top_bit()) {
AnnaBridge 165:d1b4690b3f8b 370 p_crc ^= polynomial;
AnnaBridge 165:d1b4690b3f8b 371 }
AnnaBridge 165:d1b4690b3f8b 372 data_byte <<= 1;
AnnaBridge 165:d1b4690b3f8b 373 }
AnnaBridge 165:d1b4690b3f8b 374 }
AnnaBridge 165:d1b4690b3f8b 375 } else {
AnnaBridge 165:d1b4690b3f8b 376 for (crc_data_size_t byte = 0; byte < size; byte++) {
AnnaBridge 165:d1b4690b3f8b 377 p_crc ^= (reflect_bytes(data[byte]) << (width - 8));
AnnaBridge 165:d1b4690b3f8b 378
AnnaBridge 165:d1b4690b3f8b 379 // Perform modulo-2 division, a bit at a time
AnnaBridge 165:d1b4690b3f8b 380 for (uint8_t bit = 8; bit > 0; --bit) {
AnnaBridge 165:d1b4690b3f8b 381 if (p_crc & get_top_bit()) {
AnnaBridge 165:d1b4690b3f8b 382 p_crc = (p_crc << 1) ^ polynomial;
AnnaBridge 165:d1b4690b3f8b 383 } else {
AnnaBridge 165:d1b4690b3f8b 384 p_crc = (p_crc << 1);
AnnaBridge 165:d1b4690b3f8b 385 }
AnnaBridge 165:d1b4690b3f8b 386 }
AnnaBridge 165:d1b4690b3f8b 387 }
AnnaBridge 165:d1b4690b3f8b 388 }
AnnaBridge 165:d1b4690b3f8b 389 *crc = p_crc & get_crc_mask();
AnnaBridge 165:d1b4690b3f8b 390 return 0;
AnnaBridge 165:d1b4690b3f8b 391 }
AnnaBridge 165:d1b4690b3f8b 392
AnnaBridge 165:d1b4690b3f8b 393 /** CRC computation using ROM tables
AnnaBridge 165:d1b4690b3f8b 394 *
AnnaBridge 165:d1b4690b3f8b 395 * @param buffer data buffer
AnnaBridge 165:d1b4690b3f8b 396 * @param size size of the data
AnnaBridge 165:d1b4690b3f8b 397 * @param crc CRC value is filled in, but the value is not the final
AnnaBridge 165:d1b4690b3f8b 398 * @return 0 on success or a negative error code on failure
AnnaBridge 165:d1b4690b3f8b 399 */
AnnaBridge 165:d1b4690b3f8b 400 int32_t table_compute_partial(const void *buffer, crc_data_size_t size, uint32_t *crc) const
AnnaBridge 165:d1b4690b3f8b 401 {
AnnaBridge 165:d1b4690b3f8b 402 MBED_ASSERT(crc != NULL);
AnnaBridge 165:d1b4690b3f8b 403 MBED_ASSERT(buffer != NULL);
AnnaBridge 165:d1b4690b3f8b 404
AnnaBridge 165:d1b4690b3f8b 405 const uint8_t *data = static_cast<const uint8_t *>(buffer);
AnnaBridge 165:d1b4690b3f8b 406 uint32_t p_crc = *crc;
AnnaBridge 165:d1b4690b3f8b 407 uint8_t data_byte = 0;
AnnaBridge 165:d1b4690b3f8b 408
AnnaBridge 165:d1b4690b3f8b 409 if (width <= 8) {
AnnaBridge 165:d1b4690b3f8b 410 uint8_t *crc_table = (uint8_t *)_crc_table;
AnnaBridge 165:d1b4690b3f8b 411 for (crc_data_size_t byte = 0; byte < size; byte++) {
AnnaBridge 165:d1b4690b3f8b 412 data_byte = reflect_bytes(data[byte]) ^ p_crc;
AnnaBridge 165:d1b4690b3f8b 413 p_crc = crc_table[data_byte];
AnnaBridge 165:d1b4690b3f8b 414 }
AnnaBridge 165:d1b4690b3f8b 415 } else if (width <= 16) {
AnnaBridge 165:d1b4690b3f8b 416 uint16_t *crc_table = (uint16_t *)_crc_table;
AnnaBridge 165:d1b4690b3f8b 417 for (crc_data_size_t byte = 0; byte < size; byte++) {
AnnaBridge 165:d1b4690b3f8b 418 data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8));
AnnaBridge 165:d1b4690b3f8b 419 p_crc = crc_table[data_byte] ^ (p_crc << 8);
AnnaBridge 165:d1b4690b3f8b 420 }
AnnaBridge 165:d1b4690b3f8b 421 } else {
AnnaBridge 165:d1b4690b3f8b 422 uint32_t *crc_table = (uint32_t *)_crc_table;
AnnaBridge 165:d1b4690b3f8b 423 for (crc_data_size_t byte = 0; byte < size; byte++) {
AnnaBridge 165:d1b4690b3f8b 424 data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8));
AnnaBridge 165:d1b4690b3f8b 425 p_crc = crc_table[data_byte] ^ (p_crc << 8);
AnnaBridge 165:d1b4690b3f8b 426 }
AnnaBridge 165:d1b4690b3f8b 427 }
AnnaBridge 165:d1b4690b3f8b 428 *crc = p_crc & get_crc_mask();
AnnaBridge 165:d1b4690b3f8b 429 return 0;
AnnaBridge 165:d1b4690b3f8b 430 }
AnnaBridge 165:d1b4690b3f8b 431
AnnaBridge 165:d1b4690b3f8b 432 /** Constructor init called from all specialized cases of constructor
AnnaBridge 165:d1b4690b3f8b 433 * Note: All construtor common code should be in this function.
AnnaBridge 165:d1b4690b3f8b 434 */
Anna Bridge 169:a7c7b631e539 435 void mbed_crc_ctor(void)
AnnaBridge 165:d1b4690b3f8b 436 {
AnnaBridge 165:d1b4690b3f8b 437 MBED_STATIC_ASSERT(width <= 32, "Max 32-bit CRC supported");
Anna Bridge 169:a7c7b631e539 438
Anna Bridge 169:a7c7b631e539 439 _mode = (_crc_table != NULL) ? TABLE : BITWISE;
Anna Bridge 169:a7c7b631e539 440
Anna Bridge 169:a7c7b631e539 441 #ifdef DEVICE_CRC
Anna Bridge 169:a7c7b631e539 442 crc_mbed_config_t config;
Anna Bridge 169:a7c7b631e539 443 config.polynomial = polynomial;
Anna Bridge 169:a7c7b631e539 444 config.width = width;
Anna Bridge 169:a7c7b631e539 445 config.initial_xor = _initial_value;
Anna Bridge 169:a7c7b631e539 446 config.final_xor = _final_xor;
Anna Bridge 169:a7c7b631e539 447 config.reflect_in = _reflect_data;
Anna Bridge 169:a7c7b631e539 448 config.reflect_out = _reflect_remainder;
Anna Bridge 169:a7c7b631e539 449
Anna Bridge 169:a7c7b631e539 450 if (hal_crc_is_supported(&config)) {
Anna Bridge 169:a7c7b631e539 451 _mode = HARDWARE;
Anna Bridge 169:a7c7b631e539 452 }
Anna Bridge 169:a7c7b631e539 453 #endif
AnnaBridge 165:d1b4690b3f8b 454 }
AnnaBridge 165:d1b4690b3f8b 455 };
AnnaBridge 165:d1b4690b3f8b 456
AnnaBridge 165:d1b4690b3f8b 457 #if defined ( __CC_ARM )
AnnaBridge 165:d1b4690b3f8b 458 #elif defined ( __GNUC__ )
AnnaBridge 165:d1b4690b3f8b 459 #pragma GCC diagnostic pop
AnnaBridge 165:d1b4690b3f8b 460 #endif
AnnaBridge 165:d1b4690b3f8b 461
AnnaBridge 165:d1b4690b3f8b 462 /** @}*/
AnnaBridge 165:d1b4690b3f8b 463 } // namespace mbed
AnnaBridge 165:d1b4690b3f8b 464
AnnaBridge 165:d1b4690b3f8b 465 #endif