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  1. #include <stdio.h>
  2. #include <stdint.h>
  3. int main(void) {
  4. 	// your code goes here
  5. 	uint8_t crc = 0xFF;
  6. 	uint8_t crc_new = 0;
  7. 	 uint32_t input_data = 0xD07A65;
  8. 	// uint32_t input_data = 0xA0CA85;
  9. 	//uint32_t input_data = 0x3B007C;
  10. 	for (int i = 23; i >= 0; i--)
  11. 	{
  12. 		//CRC[7] in bit 0
  13. 		uint32_t crc_xor = (crc & 0x80) >> 7;
  14. 		// if (crc_xor)
  15. 		// {
  16. 		// 	crc_xor = 0x
  17. 		// }
  18. 		//CRC_NEW = CRC << 1
  19. 		crc_new = crc << 1;
  20. 		//crc_new_bit_4 = crc_new[4] ^ crc[7]
  21. 		uint8_t crc_new_bit_4 = (crc_new & 0x10) ^ (crc_xor << 4);
  22. 		uint8_t crc_new_bit_3 = (crc_new & 0x8) ^ (crc_xor << 3);
  23. 		uint8_t crc_new_bit_2 = (crc_new & 0x4) ^ (crc_xor << 2);
  24. 		uint32_t crc_new_bit_0 = (input_data & (1 << i)) ^ (crc_xor << i);
  25. 		if (crc_new_bit_4 & 0x10)
  26. 		{
  27. 			crc_new |= 0x10;
  28. 		}
  29. 		else
  30. 		{
  31. 			crc_new &= ~0x10;
  32. 		}
  33. 		if (crc_new_bit_3 & 0x8)
  34. 		{
  35. 			crc_new |= 0x8;
  36. 		}
  37. 		else
  38. 		{
  39. 			crc_new &= ~0x8;
  40. 		}
  41. 		if (crc_new_bit_2 & 0x4)
  42. 		{
  43. 			crc_new |= 0x4;
  44. 		}
  45. 		else
  46. 		{
  47. 			crc_new &= ~0x4;
  48. 		}
  49. 		if (crc_new_bit_0 & (1 << i))
  50. 		{
  51. 			crc_new |= 0x1;
  52. 		}
  53. 		else
  54. 		{
  55. 			crc_new &= ~0x1;
  56. 		}
  57. 		crc = crc_new;
  58.  
  59. 	}
  60. 	crc ^= 0xFF;
  61. 	printf("crc=%X", crc);
  62. 	return 0;
  63. }
  64.  
Success #stdin #stdout 0.01s 5284KB
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Standard input is empty
stdout
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crc=88
https://ideone.com/F0oSkT
language:
C (gcc 8.3)
created:
30 days ago
visibility:
public

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