text: /* Macros for copying by pages; used in memcpy, memmove.  Mach version.
     Copyright (C) 1995-2016 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, see
     <http://www.gnu.org/licenses/>.  */
  
  #include <mach.h>
  
  /* Threshold at which vm_copy is more efficient than well-optimized copying
     by words.  This parameter should be tuned as necessary.  */
  #define PAGE_THRESHOLD		(2 * PAGE_SIZE)	/* XXX ? */
  
  #define PAGE_SIZE		__vm_page_size
  #define PAGE_COPY_FWD(dstp, srcp, nbytes_left, nbytes)			      \
    ((nbytes_left) = ((nbytes) -						      \
  		    (__vm_copy (__mach_task_self (),			      \
  				(vm_address_t) srcp, trunc_page (nbytes),     \
  				(vm_address_t) dstp) == KERN_SUCCESS	      \
  		     ? trunc_page (nbytes)				      \
  		     : 0)))
  