Re: extended asm+pointers

[sandeep <sandeep@codito.com>]

Ankit Jain wrote:
>       4 int main()
>       5 {
>       6   uint8_t
> a[8]={1,2,3,4,5,6,7,8},b[8]={0,0,0,0,0,0},i;
>       7   uint8_t *m,*m1;
>       8 
>       9   m=a;
>      10   m1=b;         //i have pointed m1 to b
>      11   for(i=0;i<8;i++)
>      12      printf("%d ",a[i]);
>      13   printf("\n");

>      14   asm("movq (%1), %%mm0 \n"
>      15       "movq %%mm0, (%0) \n"
>      16       :"=r"(m1)
>      17       :"r"(m)
>      18       );
this asm(...) is effectively achieving "m1=m;" you can verify this by printing 
m1[i] instead of a[i] and b[i]
>      19 
>      20   for(i=0;i<8;i++)
>      21      printf("%d ",b[i]);
>      22   return 0;
>      23 }
> well this problem is not solved yet. because when i
> display b array then it prints all 0's. according to
> me since i have initialised this m1 pointer then by b
> then b whould have all the values which i have moved
> 
> some have advised me to use arrays here as constraint
> but i want to use pointers. i am using r constraint
> and it says it says that m1 will use a register (i
> guess there is no problem in that)

-- 
regards
sandeep
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