mirror of https://github.com/marqs85/ossc.git
98 lines
4.9 KiB
C
98 lines
4.9 KiB
C
/******************************************************************************
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* *
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* License Agreement *
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* *
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* Copyright (c) 2008 Altera Corporation, San Jose, California, USA. *
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* All rights reserved. *
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* *
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* Permission is hereby granted, free of charge, to any person obtaining a *
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* copy of this software and associated documentation files (the "Software"), *
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* to deal in the Software without restriction, including without limitation *
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* the rights to use, copy, modify, merge, publish, distribute, sublicense, *
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* and/or sell copies of the Software, and to permit persons to whom the *
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* Software is furnished to do so, subject to the following conditions: *
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* *
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* The above copyright notice and this permission notice shall be included in *
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* all copies or substantial portions of the Software. *
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* *
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *
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* DEALINGS IN THE SOFTWARE. *
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* *
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* This agreement shall be governed in all respects by the laws of the State *
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* of California and by the laws of the United States of America. *
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* Altera does not recommend, suggest or require that this reference design *
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* file be used in conjunction or combination with any other product. *
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******************************************************************************/
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/**********************************************************************
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*
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* Filename: ci_crc.c
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*
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* Description: Custom instruction implementations of the CRC.
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*
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* Notes: A macro is defined that is used to access the CRC custom
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* instruction.
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*********************************************************************/
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#include "system.h"
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/*The n values and their corresponding operation are as follow:
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* n = 0, Initialize the custom instruction to the initial remainder value
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* n = 1, Write 8 bits data to custom instruction
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* n = 2, Write 16 bits data to custom instruction
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* n = 3, Write 32 bits data to custom instruction
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* n = 4, Read 32 bits data from the custom instruction
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* n = 5, Read 64 bits data from the custom instruction
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* n = 6, Read 96 bits data from the custom instruction
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* n = 7, Read 128 bits data from the custom instruction*/
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#define CRC_CI_MACRO(n, A) __builtin_custom_ini(ALT_CI_NIOS2_HW_CRC32_0_N + (n & 0x7), (A))
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unsigned long crcCI(unsigned char * input_data, unsigned long input_data_length, int do_initialize)
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{
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unsigned long index;
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/* copy of the data buffer pointer so that it can advance by different widths */
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void * input_data_copy = (void *)input_data;
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/* The custom instruction CRC will initialize to the inital remainder value */
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if (do_initialize)
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CRC_CI_MACRO(0,0);
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/* Write 32 bit data to the custom instruction. If the buffer does not end
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* on a 32 bit boundary then the remaining data will be sent to the custom
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* instruction in the 'if' statement below.
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*/
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for(index = 0; index < (input_data_length & 0xFFFFFFFC); index+=4)
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{
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CRC_CI_MACRO(3, *(unsigned long *)input_data_copy);
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input_data_copy += 4; /* void pointer, must move by 4 for each word */
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}
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/* Write the remainder of the buffer if it does not end on a word boundary */
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if((input_data_length & 0x3) == 0x3) /* 3 bytes left */
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{
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CRC_CI_MACRO(2, *(unsigned short *)input_data_copy);
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input_data_copy += 2;
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CRC_CI_MACRO(1, *(unsigned char *)input_data_copy);
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}
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else if((input_data_length & 0x3) == 0x2) /* 2 bytes left */
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{
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CRC_CI_MACRO(2, *(unsigned short *)input_data_copy);
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}
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else if((input_data_length & 0x3) == 0x1) /* 1 byte left */
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{
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CRC_CI_MACRO(1, *(unsigned char *)input_data_copy);
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}
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/* There are 4 registers in the CRC custom instruction. Since
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* this example uses CRC-32 only the first register must be read
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* in order to receive the full result.
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*/
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return CRC_CI_MACRO(4, 0);
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}
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