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  8.  
  9. #include <stdio.h>
  10. #include <stdint.h>
  11. #include <stdbool.h>
  12.  
  13.  
  14. #define __MASK_BYTE_0   0xFFu
  15. #define __MASK_BYTE_1   0xFF00u
  16. #define __MASK_BYTE_2   0xFF0000ul
  17. #define __MASK_BYTE_3   0xFF000000ul
  18.  
  19. #define __MASK_WORD_LOW   0xFFFFul
  20. #define __MASK_WORD_HI    0x0000FFFFul
  21.  
  22. #define __SHIFT_BYTE_0   0u
  23. #define __SHIFT_BYTE_1   8u
  24. #define __SHIFT_BYTE_2   16u
  25. #define __SHIFT_BYTE_3   24u
  26.  
  27.  
  28. bool isCpuLittleEndian()
  29. {
  30.     static const union {
  31.         uint32_t wordValue;
  32.         uint8_t byteValue[4];
  33.     } TEST = {0x12345678u};
  34.  
  35.    return (TEST.byteValue[0] == 0x78u);
  36. }
  37.  
  38. uint8_t WORD32_BYTE0( uint32_t word)
  39. {
  40.    return  (uint8_t)(word & __MASK_BYTE_0);
  41. }
  42.  
  43. uint8_t WORD32_BYTE1( uint32_t word)
  44. {
  45.    return  (uint8_t)(((word & __MASK_BYTE_1) >> __SHIFT_BYTE_1));
  46. }
  47.  
  48. uint8_t WORD32_BYTE2( uint32_t word)
  49. {
  50.    return  (uint8_t)(((word & __MASK_BYTE_2) >> __SHIFT_BYTE_2));
  51. }
  52.  
  53. uint8_t WORD32_BYTE3( uint32_t word)
  54. {
  55.    return  (uint8_t)(((word & __MASK_BYTE_3) >> __SHIFT_BYTE_3));
  56. }
  57.  
  58. int main()
  59. {
  60.     uint32_t val = 0x11223344;
  61.     if(isCpuLittleEndian())
  62.         printf("Little Endian\n");
  63.     else
  64.         printf("Big Endian\n");
  65.  
  66.         printf("%x\n", WORD32_BYTE0(val));
  67.  
  68.     return 0;
  69. }
Success #stdin #stdout 0.01s 5324KB
comments (?)
stdin 
123
stdout 
Little Endian
44
https://ideone.com/0L0bkR
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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