1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--                         S Y S T E M . M E M O R Y                        --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2001-2013, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This package provides the low level memory allocation/deallocation
33--  mechanisms used by GNAT for VMS 64 bit.
34
35--  To provide an alternate implementation, simply recompile the modified
36--  body of this package with gnatmake -u -a -g s-memory.adb and make sure
37--  that the ali and object files for this unit are found in the object
38--  search path.
39
40--  This unit may be used directly from an application program by providing
41--  an appropriate WITH, and the interface can be expected to remain stable.
42
43pragma Compiler_Unit_Warning;
44
45package System.Memory is
46   pragma Elaborate_Body;
47
48   type size_t is mod 2 ** Standard'Address_Size;
49   --  Note: the reason we redefine this here instead of using the
50   --  definition in Interfaces.C is that we do not want to drag in
51   --  all of Interfaces.C just because System.Memory is used.
52
53   function Alloc (Size : size_t) return System.Address;
54   --  This is the low level allocation routine. Given a size in storage
55   --  units, it returns the address of a maximally aligned block of
56   --  memory. The implementation of this routine is guaranteed to be
57   --  task safe, and also aborts are deferred if necessary.
58   --
59   --  If size_t is set to size_t'Last on entry, then a Storage_Error
60   --  exception is raised with a message "object too large".
61   --
62   --  If size_t is set to zero on entry, then a minimal (but non-zero)
63   --  size block is allocated.
64   --
65   --  Note: this is roughly equivalent to the standard C malloc call
66   --  with the additional semantics as described above.
67
68   function Alloc32 (Size : size_t) return System.Address;
69   --  Equivalent to Alloc except on VMS 64 bit where it invokes
70   --  32 bit malloc.
71
72   procedure Free (Ptr : System.Address);
73   --  This is the low level free routine. It frees a block previously
74   --  allocated with a call to Alloc. As in the case of Alloc, this
75   --  call is guaranteed task safe, and aborts are deferred.
76   --
77   --  Note: this is roughly equivalent to the standard C free call
78   --  with the additional semantics as described above.
79
80   function Realloc
81     (Ptr  : System.Address;
82      Size : size_t) return System.Address;
83   --  This is the low level reallocation routine. It takes an existing
84   --  block address returned by a previous call to Alloc or Realloc,
85   --  and reallocates the block. The size can either be increased or
86   --  decreased. If possible the reallocation is done in place, so that
87   --  the returned result is the same as the value of Ptr on entry.
88   --  However, it may be necessary to relocate the block to another
89   --  address, in which case the information is copied to the new
90   --  block, and the old block is freed. The implementation of this
91   --  routine is guaranteed to be task safe, and also aborts are
92   --  deferred as necessary.
93   --
94   --  If size_t is set to size_t'Last on entry, then a Storage_Error
95   --  exception is raised with a message "object too large".
96   --
97   --  If size_t is set to zero on entry, then a minimal (but non-zero)
98   --  size block is allocated.
99   --
100   --  Note: this is roughly equivalent to the standard C realloc call
101   --  with the additional semantics as described above.
102
103   function Realloc32
104     (Ptr  : System.Address;
105      Size : size_t) return System.Address;
106   --  Equivalent to Realloc except on VMS 64 bit where it invokes
107   --  32 bit realloc.
108
109private
110
111   --  The following names are used from the generated compiler code
112
113   pragma Export (C, Alloc,   "__gnat_malloc");
114   pragma Export (C, Alloc32, "__gnat_malloc32");
115   pragma Export (C, Free,    "__gnat_free");
116   pragma Export (C, Realloc, "__gnat_realloc");
117   pragma Export (C, Realloc32, "__gnat_realloc32");
118
119   function C_malloc32 (Size : size_t) return System.Address;
120   pragma Import (C, C_malloc32, "_malloc32");
121   --  An alias for malloc for allocating 32bit memory on 64bit VMS
122
123   function C_realloc32
124     (Ptr  : System.Address;
125      Size : size_t) return System.Address;
126   pragma Import (C, C_realloc32, "_realloc32");
127   --  An alias for realloc for allocating 32bit memory on 64bit VMS
128
129end System.Memory;
130