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  1. #include <iostream>
  2. #include <cstring>
  3. using namespace std;
  4.  
  5. int main(){
  6. 	int j;
  7.     const int n = 100000;
  8.     double *a1p, *b1p, *c1p, *d1p;
  9.  
  10. #ifdef ALLOCATE_SEPERATE
  11.     double *a1 = (double*)malloc(n * sizeof(double));
  12.     double *b1 = (double*)malloc(n * sizeof(double));
  13.     double *c1 = (double*)malloc(n * sizeof(double));
  14.     double *d1 = (double*)malloc(n * sizeof(double));
  15. #else
  16.     double *a1 = (double*)malloc(n * sizeof(double) * 4);
  17.     double *b1 = a1 + n;
  18.     double *c1 = b1 + n;
  19.     double *d1 = c1 + n;
  20. #endif
  21.  
  22.     //  Zero the data to prevent any chance of denormals.
  23.     memset(a1,0,n * sizeof(double));
  24.     memset(b1,0,n * sizeof(double));
  25.     memset(c1,0,n * sizeof(double));
  26.     memset(d1,0,n * sizeof(double));
  27.  
  28.     //  Print the addresses
  29.     cout << a1 << endl;
  30.     cout << b1 << endl;
  31.     cout << c1 << endl;
  32.     cout << d1 << endl;
  33.  
  34.     clock_t start = clock();
  35.  
  36.     int c = 0;
  37.     while (c++ < 10000){
  38.  
  39. #if ONE_LOOP
  40.         for (a1p = a1, b1p = b1, c1p = c1, d1p = d1, j = n;
  41.         	 j; a1p++, b1p++, c1p++, d1p++, j--)
  42.         {
  43.         	*a1p += *b1p;
  44.         	*c1p += *d1p;
  45.         }
  46. #else
  47.         for (a1p = a1, b1p = b1, j = n;
  48.         	 j; a1p++, b1p++, j--)
  49.         {
  50.         	*a1p += *b1p;
  51.         }
  52.         for (c1p = c1, d1p = d1, j = n;
  53.         	 j; c1p++, d1p++, j--)
  54.         {
  55.         	*c1p += *d1p;
  56.         }        
  57. #endif
  58.  
  59.     }
  60.  
  61.     clock_t end = clock();
  62.     cout << "seconds = " << (double)(end - start) / CLOCKS_PER_SEC << endl;
  63.  
  64.     system("pause");
  65.     return 0;
  66. }
Success #stdin #stdout #stderr 1.52s 6820KB
comments (?)
stdin 
Standard input is empty
stdout 
0x2ab9b1e69010
0x2ab9b1f2c510
0x2ab9b1fefa10
0x2ab9b20b2f10
seconds = 1.51273
stderr 
sh: 1: pause: not found
https://ideone.com/aJgwsp
language:
C++ (gcc 8.3)
created:
4 years ago
visibility:
public

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