汇编写下strcpy

   #include <stdio.h>

   int main()
   {
           char *source = "hello world\n";
           char dest[] = {};
           char *p = dest;
           char c = '\0';
   #if 0
  loop:
          if(*(source + i) == '\0'){
                  *(dest + i) = '\0';
                  goto exit;
          }
          *(dest + i) = *(source + i);
          i++;
          goto loop;
  exit:
  #else
          __asm__ __volatile__(
                  "ldr r2, [%2]\n"
                  "mov r0, #0\n"
                  "loop:\n"
                  "ldr r1, [%0, r0]\n"
                  "cmp r1, r2\n"
                  "beq exit\n"
                  "str r1, [%1, r0]\n"
                  "add r0, r0, #1\n"
                  "b loop\n"
                  "exit:\n"
                  :
                  :"r" (source), "r" (dest), "r" (&c)
                  :"r0", "r1", "r2", "memory"
          );
  #endif

          printf("%s\n", p);
  }

注意：最后一行要写上保护（r1,r2,r3）否则会段错误。