d                  34 kernel/string.c   char *d;
d                  40 kernel/string.c   d = dst;
d                  41 kernel/string.c   if(s < d && s + n > d){
d                  43 kernel/string.c     d += n;
d                  45 kernel/string.c       *--d = *--s;
d                  48 kernel/string.c       *d++ = *s++;