File : 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) 2001-2014, 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 3, 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. --
21 -- --
22 -- --
23 -- --
24 -- --
25 -- --
26 -- You should have received a copy of the GNU General Public License and --
27 -- a copy of the GCC Runtime Library Exception along with this program; --
28 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
29 -- <http://www.gnu.org/licenses/>. --
30 -- --
31 -- GNAT was originally developed by the GNAT team at New York University. --
32 -- Extensive contributions were provided by Ada Core Technologies Inc. --
33 -- --
34 ------------------------------------------------------------------------------
35
36 -- This package provides general block copy mechanisms analogous to those
37 -- provided by the C routines memcpy and memmove allowing for copies with
38 -- and without possible overlap of the operands.
39
40 -- The idea is to allow a configurable run-time to provide this capability
41 -- for use by the compiler without dragging in C-run time routines.
42
43 with System.CRTL;
44 -- The above with is contrary to the intent ???
45
46 package System.Memory_Copy is
47 pragma Preelaborate;
48
49 procedure memcpy (S1 : Address; S2 : Address; N : System.CRTL.size_t)
50 renames System.CRTL.memcpy;
51 -- Copies N storage units from area starting at S2 to area starting
52 -- at S1 without any check for buffer overflow. The memory areas
53 -- must not overlap, or the result of this call is undefined.
54
55 procedure memmove (S1 : Address; S2 : Address; N : System.CRTL.size_t)
56 renames System.CRTL.memmove;
57 -- Copies N storage units from area starting at S2 to area starting
58 -- at S1 without any check for buffer overflow. The difference between
59 -- this memmove and memcpy is that with memmove, the storage areas may
60 -- overlap (forwards or backwards) and the result is correct (i.e. it
61 -- is as if S2 is first moved to a temporary area, and then this area
62 -- is copied to S1 in a separate step).
63
64 -- In the standard library, these are just interfaced to the C routines.
65 -- But in the HI-E (high integrity version) they may be reprogrammed to
66 -- meet certification requirements (and marked High_Integrity).
67
68 -- Note that in high integrity mode these routines are by default not
69 -- available, and the HI-E compiler will as a result generate implicit
70 -- loops (which will violate the restriction No_Implicit_Loops).
71
72 end System.Memory_Copy;