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  1. #include <bits/stdc++.h>
  2.  
  3. #define SIZ 10000
  4.  
  5. int asmgcd(int a, int b)
  6. {
  7.     /* Compute Greatest Common Divisor using Euclid's Algorithm */
  8.     int result ;
  9.     __asm__ __volatile__ (
  10.         "movl %1, %%eax;"
  11.         "movl %2, %%ebx;"
  12.         "CONTD: cmpl $0, %%ebx;"
  13.         "je DONE;"
  14.         "xorl %%edx, %%edx;"
  15.         "idivl %%ebx;"
  16.         "movl %%ebx, %%eax;"
  17.         "movl %%edx, %%ebx;"
  18.         "jmp CONTD;"
  19.         "DONE: movl %%eax, %0;"
  20.         : "=g" (result)  //outputs
  21.         : "g" (a), "g" (b) //inputs
  22.     );
  23.  
  24.     return result;
  25. }
  26.  
  27. inline int mygcd1(register int a, register int b)
  28. {
  29.     while(b)
  30.     {
  31.         register int c = b;
  32.         b = a % c;
  33.         a = c;
  34.     }
  35.     return a;
  36. }
  37.  
  38. inline int mygcd2(int a, int b)
  39. {
  40.     while(b)
  41.     {
  42.         register int c = b;
  43.         b = a % c;
  44.         a = c;
  45.     }
  46.     return a;
  47. }
  48.  
  49. inline int mygcd3(int a, int b)
  50. {
  51.     while(b)
  52.     {
  53.         int c = b;
  54.         b = a % c;
  55.         a = c;
  56.     }
  57.     return a;
  58. }
  59.  
  60. int recur_gcd(int a, int b)
  61. {
  62.     if(b == 0) return a;
  63.     return recur_gcd(b, a % b);
  64. }
  65.  
  66. int functest(int (*gcdfunc)(int, int))
  67. {
  68.     int i, j;
  69.     time_t start, stop;
  70.  
  71.     int g = 0;
  72.     start = clock();
  73.     for(i = 1; i < SIZ; ++i)
  74.     {
  75.         for(j = 1; j <= i; ++j)
  76.         {
  77.             g += (gcdfunc(i, j) == 1);
  78.         }
  79.     }
  80.     stop = clock();
  81.  
  82.     //printf("result = %d\n", g);
  83.     printf("Time: %lf sec\n\n", (double)(stop - start) / CLOCKS_PER_SEC);
  84. }
  85.  
  86. int main()
  87. {
  88.     puts("STD's gcd:");
  89.     functest(std::__gcd);
  90.  
  91.     puts("ASM GCD:");
  92.     functest(asmgcd);
  93.  
  94.     puts("parameter and variable both registers:");
  95.     functest(mygcd1);
  96.  
  97.     puts("parameter normal, variable register:");
  98.     functest(mygcd2);
  99.  
  100.     puts("parameter and variable both normal:");
  101.     functest(mygcd3);
  102.  
  103.     puts("recursive gcd:");
  104.     functest(recur_gcd);
  105.  
  106.     return 0;
  107. }
  108.  
Time limit exceeded #stdin #stdout 15s 3412KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/ztG05G
GCD Benchmark Test
language:
C++ (gcc 8.3)
created:
8 years ago
visibility:
secret

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