nsz Git - libfirm/blob - ir/be/test/llvm/DuffsDevice.c

   1 /* This silly testcase is here to check that "Duff's Device" works properly
   2  * in LLVM.  Guess what, it does.  :)
   3  *
   4  * For more info, see: http://www.lysator.liu.se/c/duffs-device.html
   5  */
   6
   7 #include <stdio.h>
   8
   9         sum(to, from, count)
  10         register short *to, *from;
  11         register count;
  12         {
  13                 register n=(count+7)/8;
  14                 switch(count%8){
  15                 case 0: do{     *to += *from++;
  16                 case 7:         *to += *from++;
  17                 case 6:         *to += *from++;
  18                 case 5:         *to += *from++;
  19                 case 4:         *to += *from++;
  20                 case 3:         *to += *from++;
  21                 case 2:         *to += *from++;
  22                 case 1:         *to += *from++;
  23                         }while(--n>0);
  24                 }
  25         }
  26
  27 int main() {
  28         short Array[100];
  29         short Sum = 0;
  30         int i;
  31
  32         for (i = 0; i != 100; ++i)
  33                 Array[i] = i;
  34
  35         sum(&Sum, Array, 100);
  36
  37         printf("Sum is %d\n", Sum);
  38
  39         return 0;
  40 }