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  1. #include <stdint.h>
  2. #include <stdio.h>
  3.  
  4. void format_binary(uint64_t x, char *buf)
  5. {
  6.     int i = 0;
  7.     while(x){
  8.         char b = x % 2;
  9.         buf[i] = b + '0';
  10.         x /= 2;
  11.         i++;
  12.     }
  13.     int m = i / 2;
  14.     for(int j = 0; j < m; j++){
  15.         char tmp = buf[j];
  16.         buf[j] = buf[i - 1 - j];
  17.         buf[i - 1 - j] = tmp;
  18.     }
  19.     buf[i] = '\0';
  20. }
  21.  
  22. static inline uint64_t interleave64(uint32_t xlo, uint32_t ylo) {
  23.     static const uint64_t B[] = {0x5555555555555555ULL, 0x3333333333333333ULL,
  24.                                  0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
  25.                                  0x0000FFFF0000FFFFULL};
  26.     char bf[200];
  27.     for(int i = 0; i < 5; i++){
  28.         format_binary(B[i], bf);
  29.         printf("B[%d]=(%lx)%s\n", i, B[i], bf);
  30.     }
  31.     static const unsigned int S[] = {1, 2, 4, 8, 16};
  32.  
  33.     uint64_t x = xlo;
  34.     uint64_t y = ylo;
  35.     format_binary(x, bf);
  36.     printf("x (%lx)%s \n", x, bf);
  37.     format_binary(y, bf);
  38.     printf("y (%lx)%s \n", y, bf);
  39.  
  40.     x = (x | (x << S[4])) & B[4];
  41.     y = (y | (y << S[4])) & B[4];
  42.     format_binary(x, bf);
  43.     printf("S 4: x (%lx)%s \n", x, bf);
  44.     format_binary(y, bf);
  45.     printf("S 4: y (%lx)%s \n", y, bf);
  46.  
  47.     x = (x | (x << S[3])) & B[3];
  48.     y = (y | (y << S[3])) & B[3];
  49.     format_binary(x, bf);
  50.     printf("S 3: x (%lx)%s \n", x, bf);
  51.     format_binary(y, bf);
  52.     printf("S 3: y (%lx)%s \n", y, bf);
  53.  
  54.     x = (x | (x << S[2])) & B[2];
  55.     y = (y | (y << S[2])) & B[2];
  56.     format_binary(x, bf);
  57.     printf("S 2: x (%lx)%s \n", x, bf);
  58.     format_binary(y, bf);
  59.     printf("S 2: y (%lx)%s \n", y, bf);
  60.  
  61.     x = (x | (x << S[1])) & B[1];
  62.     y = (y | (y << S[1])) & B[1];
  63.     format_binary(x, bf);
  64.     printf("S 1: x (%lx)%s \n", x, bf);
  65.     format_binary(y, bf);
  66.     printf("S 1: y (%lx)%s \n", y, bf);
  67.  
  68.     x = (x | (x << S[0])) & B[0];
  69.     y = (y | (y << S[0])) & B[0];
  70.     format_binary(x, bf);
  71.     printf("S 0: x (%lx)%s \n", x, bf);
  72.     format_binary(y, bf);
  73.     printf("S 0: y (%lx)%s \n", y, bf);
  74.  
  75.     return x | (y << 1);
  76. }
  77.  
  78. int main(){
  79. 	interleave64(0xffffffff, 0);
  80. }
Success #stdin #stdout 0s 4520KB
comments (?)
stdin
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Standard input is empty
stdout
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B[0]=(5555555555555555)101010101010101010101010101010101010101010101010101010101010101
B[1]=(3333333333333333)11001100110011001100110011001100110011001100110011001100110011
B[2]=(f0f0f0f0f0f0f0f)111100001111000011110000111100001111000011110000111100001111
B[3]=(ff00ff00ff00ff)11111111000000001111111100000000111111110000000011111111
B[4]=(ffff0000ffff)111111111111111100000000000000001111111111111111
x (ffffffff)11111111111111111111111111111111 
y (0) 
S 4: x (ffff0000ffff)111111111111111100000000000000001111111111111111 
S 4: y (0) 
S 3: x (ff00ff00ff00ff)11111111000000001111111100000000111111110000000011111111 
S 3: y (0) 
S 2: x (f0f0f0f0f0f0f0f)111100001111000011110000111100001111000011110000111100001111 
S 2: y (0) 
S 1: x (3333333333333333)11001100110011001100110011001100110011001100110011001100110011 
S 1: y (0) 
S 0: x (5555555555555555)101010101010101010101010101010101010101010101010101010101010101 
S 0: y (0)
https://ideone.com/tajz9a
language:
C++14 (gcc 8.3)
created:
3 years ago
visibility:
public

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