From 531a83ebd2b03da64656debacc8105f6cbe261ec Mon Sep 17 00:00:00 2001 From: deepikabhavnani Date: Wed, 8 Aug 2018 13:56:42 -0500 Subject: [PATCH 1/2] Add optimized implementation of 32-bit ANSI CRC --- drivers/MbedCRC.h | 13 +++++++++---- drivers/TableCRC.cpp | 38 +++++--------------------------------- drivers/TableCRC.h | 5 +++-- 3 files changed, 17 insertions(+), 39 deletions(-) diff --git a/drivers/MbedCRC.h b/drivers/MbedCRC.h index 1221c4fe0b..7d69721db9 100644 --- a/drivers/MbedCRC.h +++ b/drivers/MbedCRC.h @@ -242,7 +242,12 @@ public: if ((width < 8) && (NULL == _crc_table)) { 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; } @@ -420,9 +425,9 @@ private: } } else { uint32_t *crc_table = (uint32_t *)_crc_table; - for (crc_data_size_t byte = 0; byte < size; byte++) { - data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8)); - p_crc = crc_table[data_byte] ^ (p_crc << 8); + for (crc_data_size_t i = 0; i < size; i++) { + p_crc = (p_crc >> 4) ^ crc_table[(p_crc ^ (data[i] >> 0)) & 0xf]; + p_crc = (p_crc >> 4) ^ crc_table[(p_crc ^ (data[i] >> 4)) & 0xf]; } } *crc = p_crc & get_crc_mask(); diff --git a/drivers/TableCRC.cpp b/drivers/TableCRC.cpp index b63cfcaaf7..f3cb42158a 100644 --- a/drivers/TableCRC.cpp +++ b/drivers/TableCRC.cpp @@ -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 }; -extern const uint32_t Table_CRC_32bit_ANSI[MBED_CRC_TABLE_SIZE] = { - 0x0, 0x4c11db7, 0x9823b6e, 0xd4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, - 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, - 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75, - 0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd, - 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 +extern const uint32_t Table_CRC_32bit_ANSI[MBED_OPTIMIZED_CRC_TABLE_SIZE] = { + 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, + 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c, + 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, + 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c }; /** @}*/ diff --git a/drivers/TableCRC.h b/drivers/TableCRC.h index 224e14e532..6a87159157 100644 --- a/drivers/TableCRC.h +++ b/drivers/TableCRC.h @@ -23,13 +23,14 @@ namespace mbed { /** \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_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_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 From f593555cbb018492cd5018c584a2ba98194e6eff Mon Sep 17 00:00:00 2001 From: deepikabhavnani Date: Wed, 8 Aug 2018 13:56:13 -0500 Subject: [PATCH 2/2] Guard hardware related implementation into DEVICE_CRC --- drivers/MbedCRC.h | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/MbedCRC.h b/drivers/MbedCRC.h index 7d69721db9..ff3b8f4f9f 100644 --- a/drivers/MbedCRC.h +++ b/drivers/MbedCRC.h @@ -95,7 +95,14 @@ namespace mbed { template class MbedCRC { public: - enum CrcMode { HARDWARE = 0, TABLE, BITWISE }; + enum CrcMode + { +#ifdef DEVICE_CRC + HARDWARE = 0, +#endif + TABLE = 1, + BITWISE + }; public: typedef uint64_t crc_data_size_t; @@ -170,12 +177,12 @@ public: int32_t compute_partial(void *buffer, crc_data_size_t size, uint32_t *crc) { switch (_mode) { - case HARDWARE: #ifdef DEVICE_CRC + case HARDWARE: hal_crc_compute_partial((uint8_t *)buffer, size); -#endif // DEVICE_CRC *crc = 0; return 0; +#endif case TABLE: return table_compute_partial(buffer, size, crc); case BITWISE: @@ -229,15 +236,12 @@ public: { MBED_ASSERT(crc != NULL); - if (_mode == HARDWARE) { #ifdef DEVICE_CRC + if (_mode == HARDWARE) { *crc = hal_crc_get_result(); return 0; -#else - return -1; -#endif } - +#endif uint32_t p_crc = *crc; if ((width < 8) && (NULL == _crc_table)) { p_crc = (uint32_t)(p_crc << (8 - width));