com32/lib/memmove.c

   1 /*
   2  * memmove.c
   3  */
   4
   5 #include <string.h>
   6
   7 void *memmove(void *dst, const void *src, size_t n)
   8 {
   9   const char *p = src;
  10   char *q = dst;
  11 #if defined(__i386__) || defined(__x86_64__)
  12   if ( q < p ) {
  13     asm volatile("cld ; rep ; movsb" : "+c" (n), "+S" (p), "+D" (q));
  14   } else {
  15     p += (n-1);
  16     q += (n-1);
  17     asm volatile("std ; rep ; movsb" : "+c" (n), "+S" (p), "+D" (q));
  18   }
  19 #else
  20   if ( q < p ) {
  21     while ( n-- ) {
  22       *q++ = *p++;
  23     }
  24   } else {
  25     p += n;
  26     q += n;
  27     while ( n-- ) {
  28       *--q = *--p;
  29     }
  30   }
  31 #endif
  32
  33   return dst;
  34 }