1  /* Macros for copying by pages; used in memcpy, memmove.
       2     Copyright (C) 1995-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  /* The macro PAGE_COPY_FWD_MAYBE defined in memcopy.h is used in memmove if the
      20     PAGE_COPY_THRESHOLD macro is set to a non-zero value.  The default is 0,
      21     that is copying by pages is not implemented.
      22  
      23     System-specific pagecopy.h files that want to support page copying should
      24     define these macros:
      25  
      26     PAGE_COPY_THRESHOLD
      27     -- A non-zero minimum size for which virtual copying by pages is worthwhile.
      28  
      29     PAGE_SIZE
      30     -- Size of a page.
      31  
      32     PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes)
      33     -- Macro to perform the virtual copy operation.
      34     The pointers will be aligned to PAGE_SIZE bytes.
      35  */
      36  
      37  #define PAGE_COPY_THRESHOLD 0