hello,all

The following program is from MARVELL U-Boot

 

 

if(mvCtrlModelGet() == MV_5281_DEV_ID) /* Orion 2 */
 {

  __asm__ __volatile__("mrc    p15, 0, %0, c14, c0, 0" : "=r" (temp):: "memory");
  if (temp & 0x10000000)
  {
   printf("CPU: Write allocate enabled\n");
  }
  else
  {
   printf("CPU: Write allocate Disabled\n");
  }
 }

 

 

I don't understand what's the following sentense mean,please detailed explain it,thanks

 

__asm__ __volatile__("mrc    p15, 0, %0, c14, c0, 0" : "=r" (temp):: "memory");