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  1. #include <iostream>
  2. #include <iomanip>
  3.  
  4. using namespace std;
  5.  
  6. static unsigned short * lookup = NULL;
  7.  
  8. void t1_init()
  9. {
  10.     lookup = new unsigned short [1 << 16];
  11.     for (int i = 0; i < 1 << 16; ++i)
  12.         lookup[i] = 
  13.         ((i & 0xf000) ? 0 : 0xf000) |
  14.         ((i & 0xf00) ? 0 : 0xf00) |
  15.         ((i & 0xf0) ? 0 : 0xf0) |
  16.         ((i & 0xf) ? 0 : 0xf);
  17. }
  18.  
  19. unsigned int transform1(unsigned int value)
  20. {
  21.     return 
  22.            (lookup[((value >> 0 ) & 0xFFFF)] << 0 )  |
  23.            (lookup[((value >> 16) & 0xFFFF)] << 16);
  24. }
  25.  
  26. unsigned int transform2(unsigned int hexval)
  27. {
  28.    return
  29.     ((hexval & 0xf0000000) ? 0 : 0xf0000000) |
  30.     ((hexval & 0xf000000) ? 0 : 0xf000000) |
  31.     ((hexval & 0xf00000) ? 0 : 0xf00000) |
  32.     ((hexval & 0xf0000) ? 0 : 0xf0000) |
  33.     ((hexval & 0xf000) ? 0 : 0xf000) |
  34.     ((hexval & 0xf00) ? 0 : 0xf00) |
  35.     ((hexval & 0xf0) ? 0 : 0xf0) |
  36.     ((hexval & 0xf) ? 0 : 0xf);
  37. }
  38.  
  39. unsigned int transform3(unsigned int n)
  40. {
  41.     return ~(n | ((n & 0x77777777) << 1) | ((n & 0x88888888) >> 3)
  42.                | ((n & 0x33333333) << 2) | ((n & 0xCCCCCCCC) >> 2)
  43.                | ((n & 0x11111111) << 3) | ((n & 0xEEEEEEEE) >> 1));
  44. }
  45.  
  46. unsigned int transform4(unsigned int in) {
  47.     return (
  48.         ((in & (0xF << 28)) ? 0x0 : (0xF << 28)) |
  49.         ((in & (0xF << 24)) ? 0x0 : (0xF << 24)) |
  50.         ((in & (0xF << 20)) ? 0x0 : (0xF << 20)) |
  51.         ((in & (0xF << 16)) ? 0x0 : (0xF << 16)) |
  52.         ((in & (0xF << 12)) ? 0x0 : (0xF << 12)) |
  53.         ((in & (0xF << 8)) ? 0x0 : (0xF << 8)) |
  54.         ((in & (0xF << 4)) ? 0x0 : (0xF << 4)) |
  55.         ((in & (0xF << 0)) ? 0x0 : (0xF << 0))
  56.     );
  57. }
  58.  
  59. int main(int c, char * v[])
  60. {
  61.     t1_init();
  62.     int i, j = 0x34005600, k, l;
  63.     bool testing = false;
  64.     unsigned int(* transform)(unsigned int) = transform4;
  65.     unsigned int(* transform_compare)(unsigned int) = transform4;
  66.  
  67.     if (testing)
  68.         for (i = 0; i < 1000; ++i)
  69.         {
  70.             l = j;
  71.             k = transform_compare(j & i);
  72.             j = transform(j & i);
  73.             if (j != k)
  74.                 cout << "Differing value: " <<
  75.                 setfill('0') << setw(8) << hex << (l & i) << " -> " <<
  76.                 setfill('0') << setw(8) << hex << j << ":" <<
  77.                 setfill('0') << setw(8) << hex << k << endl;
  78.         }
  79.     else
  80.         for (i = 0; i < 10000000; ++i)
  81.         {
  82.             j = transform(j & i);
  83.             j = transform(j & i);
  84.             j = transform(j & i);
  85.             j = transform(j & i);
  86.             j = transform(j & i);
  87.             j = transform(j & i);
  88.             j = transform(j & i);
  89.             j = transform(j & i);
  90.             j = transform(j & i);
  91.             j = transform(j & i);
  92.         }
  93.     return j & 0xFFFFFF00;
  94. }
Success #stdin #stdout 1.13s 2852KB
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https://ideone.com/64XFe
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
secret

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