1 ------------------------------------------------------------------------------
3 -- GNU ADA RUNTIME LIBRARY COMPONENTS --
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 _ 8 --
9 -- Copyright (C) 2002-2004 Free Software Foundation, Inc. --
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 2, 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with Unchecked_Conversion;
36 package body System.Compare_Array_Unsigned_8 is
38 function "+" (Left, Right : Address) return Address;
39 pragma Import (Intrinsic, "+");
40 -- Provide addition operation on type Address (this may not be directly
41 -- available if type System.Address is non-private and the operations on
42 -- the type are made abstract to hide them from public users of System.
44 type Word is mod 2 ** 32;
45 -- Used to process operands by words
47 type Big_Words is array (Natural) of Word;
48 type Big_Words_Ptr is access Big_Words;
49 -- Array type used to access by words
51 type Byte is mod 2 ** 8;
52 -- Used to process operands by bytes
54 type Big_Bytes is array (Natural) of Byte;
55 type Big_Bytes_Ptr is access Big_Bytes;
56 -- Array type used to access by bytes
58 function To_Big_Words is new
59 Unchecked_Conversion (System.Address, Big_Words_Ptr);
61 function To_Big_Bytes is new
62 Unchecked_Conversion (System.Address, Big_Bytes_Ptr);
64 ----------------------
65 -- Compare_Array_U8 --
66 ----------------------
68 function Compare_Array_U8
69 (Left : System.Address;
70 Right : System.Address;
75 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
78 -- If operands are non-aligned, or length is too short, go by bytes
80 if (((Left or Right) and 2#11#) /= 0) or else Compare_Len < 4 then
81 return Compare_Array_U8_Unaligned (Left, Right, Left_Len, Right_Len);
84 -- Here we can go by words
87 LeftP : constant Big_Words_Ptr := To_Big_Words (Left);
88 RightP : constant Big_Words_Ptr := To_Big_Words (Right);
89 Clen4 : constant Natural := Compare_Len / 4 - 1;
90 Clen4F : constant Natural := Clen4 * 4;
93 for J in 0 .. Clen4 loop
94 if LeftP (J) /= RightP (J) then
95 return Compare_Array_U8_Unaligned
96 (Left + Address (4 * J),
97 Right + Address (4 * J),
102 return Compare_Array_U8_Unaligned
103 (Left + Address (Clen4F),
104 Right + Address (Clen4F),
108 end Compare_Array_U8;
110 --------------------------------
111 -- Compare_Array_U8_Unaligned --
112 --------------------------------
114 function Compare_Array_U8_Unaligned
115 (Left : System.Address;
116 Right : System.Address;
121 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
123 LeftP : constant Big_Bytes_Ptr := To_Big_Bytes (Left);
124 RightP : constant Big_Bytes_Ptr := To_Big_Bytes (Right);
127 for J in 0 .. Compare_Len - 1 loop
128 if LeftP (J) /= RightP (J) then
129 if LeftP (J) > RightP (J) then
137 if Left_Len = Right_Len then
139 elsif Left_Len > Right_Len then
144 end Compare_Array_U8_Unaligned;
146 end System.Compare_Array_Unsigned_8;