1------------------------------------------------------------------------------
2--                                                                          --
3--                    GNAT RUN-TIME LIBRARY COMPONENTS                      --
4--                                                                          --
5--      S Y S T E M . C O M P A R E _ A R R A Y _ U N S I G N E D _ 3 2     --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 2002-2009, 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
32with System.Address_Operations; use System.Address_Operations;
33
34with Ada.Unchecked_Conversion;
35
36package body System.Compare_Array_Unsigned_32 is
37
38   type Word is mod 2 ** 32;
39   for Word'Size use 32;
40   --  Used to process operands by words
41
42   type Uword is new Word;
43   for Uword'Alignment use 1;
44   --  Used to process operands when unaligned
45
46   type WP is access Word;
47   type UP is access Uword;
48
49   function W is new Ada.Unchecked_Conversion (Address, WP);
50   function U is new Ada.Unchecked_Conversion (Address, UP);
51
52   -----------------------
53   -- Compare_Array_U32 --
54   -----------------------
55
56   function Compare_Array_U32
57     (Left      : System.Address;
58      Right     : System.Address;
59      Left_Len  : Natural;
60      Right_Len : Natural) return Integer
61   is
62      Clen : Natural := Natural'Min (Left_Len, Right_Len);
63      --  Number of elements left to compare
64
65      L : Address := Left;
66      R : Address := Right;
67      --  Pointers to next elements to compare
68
69   begin
70      --  Case of going by aligned words
71
72      if ModA (OrA (Left, Right), 4) = 0 then
73         while Clen /= 0 loop
74            if W (L).all /= W (R).all then
75               if W (L).all > W (R).all then
76                  return +1;
77               else
78                  return -1;
79               end if;
80            end if;
81
82            Clen := Clen - 1;
83            L := AddA (L, 4);
84            R := AddA (R, 4);
85         end loop;
86
87      --  Case of going by unaligned words
88
89      else
90         while Clen /= 0 loop
91            if U (L).all /= U (R).all then
92               if U (L).all > U (R).all then
93                  return +1;
94               else
95                  return -1;
96               end if;
97            end if;
98
99            Clen := Clen - 1;
100            L := AddA (L, 4);
101            R := AddA (R, 4);
102         end loop;
103      end if;
104
105      --  Here if common section equal, result decided by lengths
106
107      if Left_Len = Right_Len then
108         return 0;
109      elsif Left_Len > Right_Len then
110         return +1;
111      else
112         return -1;
113      end if;
114   end Compare_Array_U32;
115
116end System.Compare_Array_Unsigned_32;
117