gcc/ada/s-memcop.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                   S Y S T E M . M E M O R Y _ C O P Y                    --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2001-2005 Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- This specification is derived from the Ada Reference Manual for use with --
  12 -- GNAT. The copyright notice above, and the license provisions that follow --
  13 -- apply solely to the  contents of the part following the private keyword. --
  14 --                                                                          --
  15 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  16 -- terms of the  GNU General Public License as published  by the Free Soft- --
  17 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  18 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  19 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  20 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  21 -- for  more details.  You should have  received  a copy of the GNU General --
  22 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  23 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  24 -- Boston, MA 02110-1301, USA.                                              --
  25 --                                                                          --
  26 -- As a special exception,  if other files  instantiate  generics from this --
  27 -- unit, or you link  this unit with other files  to produce an executable, --
  28 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  29 -- covered  by the  GNU  General  Public  License.  This exception does not --
  30 -- however invalidate  any other reasons why  the executable file  might be --
  31 -- covered by the  GNU Public License.                                      --
  32 --                                                                          --
  33 -- GNAT was originally developed  by the GNAT team at  New York University. --
  34 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  35 --                                                                          --
  36 ------------------------------------------------------------------------------
  37
  38 --  This package provides general block copy mechanisms analogous to those
  39 --  provided by the C routines memcpy and memmove allowing for copies with
  40 --  and without possible overlap of the operands.
  41
  42 --  The idea is to allow a configurable run-time to provide this capability
  43 --  for use by the compiler without dragging in C-run time routines.
  44
  45 with System.CRTL;
  46 --  The above with is contrary to the intent ???
  47
  48 package System.Memory_Copy is
  49    pragma Preelaborate;
  50
  51    procedure memcpy (S1 : Address; S2 : Address; N : System.CRTL.size_t)
  52      renames System.CRTL.memcpy;
  53    --  Copies N storage units from area starting at S2 to area starting
  54    --  at S1 without any check for buffer overflow. The memory areas
  55    --  must not overlap, or the result of this call is undefined.
  56
  57    procedure memmove (S1 : Address; S2 : Address; N : System.CRTL.size_t)
  58       renames System.CRTL.memmove;
  59    --  Copies N storage units from area starting at S2 to area starting
  60    --  at S1 without any check for buffer overflow. The difference between
  61    --  this memmove and memcpy is that with memmove, the storage areas may
  62    --  overlap (forwards or backwards) and the result is correct (i.e. it
  63    --  is as if S2 is first moved to a temporary area, and then this area
  64    --  is copied to S1 in a separate step).
  65
  66    --  In the standard library, these are just interfaced to the C routines.
  67    --  But in the HI-E (high integrity version) they may be reprogrammed to
  68    --  meet certification requirements (and marked High_Integrity).
  69
  70    --  Note that in high integrity mode these routines are by default not
  71    --  available, and the HI-E compiler will as a result generate implicit
  72    --  loops (which will violate the restriction No_Implicit_Loops).
  73
  74 end System.Memory_Copy;