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Add optimized implementation of 32-bit ANSI CRC

pull/7735/head
deepikabhavnani 2018-08-08 13:56:42 -05:00
parent 546dafbadc
commit 531a83ebd2
3 changed files with 17 additions and 39 deletions
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13
drivers/MbedCRC.h
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@ -242,7 +242,12 @@ public:
if ((width < 8) && (NULL == _crc_table)) { if ((width < 8) && (NULL == _crc_table)) {
p_crc = (uint32_t)(p_crc << (8 - width)); p_crc = (uint32_t)(p_crc << (8 - width));
} }
*crc = (reflect_remainder(p_crc) ^ _final_xor) & get_crc_mask(); // Optimized algorithm for 32BitANSI does not need additional reflect_remainder
if ((TABLE == _mode) && (POLY_32BIT_ANSI == polynomial)) {
*crc = (p_crc ^ _final_xor) & get_crc_mask();
} else {
*crc = (reflect_remainder(p_crc) ^ _final_xor) & get_crc_mask();
}
return 0; return 0;
} }
@ -420,9 +425,9 @@ private:
} }
} else { } else {
uint32_t *crc_table = (uint32_t *)_crc_table; uint32_t *crc_table = (uint32_t *)_crc_table;
for (crc_data_size_t byte = 0; byte < size; byte++) { for (crc_data_size_t i = 0; i < size; i++) {
data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8)); p_crc = (p_crc >> 4) ^ crc_table[(p_crc ^ (data[i] >> 0)) & 0xf];
p_crc = crc_table[data_byte] ^ (p_crc << 8); p_crc = (p_crc >> 4) ^ crc_table[(p_crc ^ (data[i] >> 4)) & 0xf];
} }
} }
*crc = p_crc & get_crc_mask(); *crc = p_crc & get_crc_mask();

38
drivers/TableCRC.cpp
View File

@ -108,39 +108,11 @@ extern const uint16_t Table_CRC_16bit_IBM[MBED_CRC_TABLE_SIZE] = {
0x220, 0x8225, 0x822f, 0x22a, 0x823b, 0x23e, 0x234, 0x8231, 0x8213, 0x216, 0x21c, 0x8219 0x220, 0x8225, 0x822f, 0x22a, 0x823b, 0x23e, 0x234, 0x8231, 0x8213, 0x216, 0x21c, 0x8219
}; };
extern const uint32_t Table_CRC_32bit_ANSI[MBED_CRC_TABLE_SIZE] = { extern const uint32_t Table_CRC_32bit_ANSI[MBED_OPTIMIZED_CRC_TABLE_SIZE] = {
0x0, 0x4c11db7, 0x9823b6e, 0xd4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75, 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x18aeb13, 0x54bf6a4, 0x808d07d, 0xcc9cdca,
0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
0x315d626, 0x7d4cb91, 0xa97ed48, 0xe56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x29f3d35, 0x65e2082, 0xb1d065b, 0xfdc1bec,
0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
}; };
/** @}*/ /** @}*/

5
drivers/TableCRC.h
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@ -23,13 +23,14 @@ namespace mbed {
/** \addtogroup drivers */ /** \addtogroup drivers */
/** @{*/ /** @{*/
#define MBED_CRC_TABLE_SIZE 256 #define MBED_CRC_TABLE_SIZE 256
#define MBED_OPTIMIZED_CRC_TABLE_SIZE 16
extern const uint8_t Table_CRC_7Bit_SD[MBED_CRC_TABLE_SIZE]; extern const uint8_t Table_CRC_7Bit_SD[MBED_CRC_TABLE_SIZE];
extern const uint8_t Table_CRC_8bit_CCITT[MBED_CRC_TABLE_SIZE]; extern const uint8_t Table_CRC_8bit_CCITT[MBED_CRC_TABLE_SIZE];
extern const uint16_t Table_CRC_16bit_CCITT[MBED_CRC_TABLE_SIZE]; extern const uint16_t Table_CRC_16bit_CCITT[MBED_CRC_TABLE_SIZE];
extern const uint16_t Table_CRC_16bit_IBM[MBED_CRC_TABLE_SIZE]; extern const uint16_t Table_CRC_16bit_IBM[MBED_CRC_TABLE_SIZE];
extern const uint32_t Table_CRC_32bit_ANSI[MBED_CRC_TABLE_SIZE]; extern const uint32_t Table_CRC_32bit_ANSI[MBED_OPTIMIZED_CRC_TABLE_SIZE];
/** @}*/ /** @}*/
} // namespace mbed } // namespace mbed