1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY COMPONENTS --
5 -- S Y S T E M . C O M P A R E _ A R R A Y _ S I G N E D _ 8 --
9 -- Copyright (C) 2002-2007, 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, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, 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 System.Address_Operations; use System.Address_Operations;
36 with Ada.Unchecked_Conversion;
38 package body System.Compare_Array_Signed_8 is
40 type Word is mod 2 ** 32;
41 -- Used to process operands by words
43 type Big_Words is array (Natural) of Word;
44 type Big_Words_Ptr is access Big_Words;
45 -- Array type used to access by words
47 type Byte is range -128 .. +127;
49 -- Used to process operands by bytes
51 type Big_Bytes is array (Natural) of Byte;
52 type Big_Bytes_Ptr is access Big_Bytes;
53 -- Array type used to access by bytes
55 function To_Big_Words is new
56 Ada.Unchecked_Conversion (System.Address, Big_Words_Ptr);
58 function To_Big_Bytes is new
59 Ada.Unchecked_Conversion (System.Address, Big_Bytes_Ptr);
61 ----------------------
62 -- Compare_Array_S8 --
63 ----------------------
65 function Compare_Array_S8
66 (Left : System.Address;
67 Right : System.Address;
69 Right_Len : Natural) return Integer
71 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
74 -- If operands are non-aligned, or length is too short, go by bytes
76 if ModA (OrA (Left, Right), 4) /= 0 or else Compare_Len < 4 then
77 return Compare_Array_S8_Unaligned (Left, Right, Left_Len, Right_Len);
80 -- Here we can go by words
83 LeftP : constant Big_Words_Ptr :=
85 RightP : constant Big_Words_Ptr :=
87 Words_To_Compare : constant Natural := Compare_Len / 4;
88 Bytes_Compared_As_Words : constant Natural := Words_To_Compare * 4;
91 for J in 0 .. Words_To_Compare - 1 loop
92 if LeftP (J) /= RightP (J) then
93 return Compare_Array_S8_Unaligned
94 (AddA (Left, Address (4 * J)),
95 AddA (Right, Address (4 * J)),
100 return Compare_Array_S8_Unaligned
101 (AddA (Left, Address (Bytes_Compared_As_Words)),
102 AddA (Right, Address (Bytes_Compared_As_Words)),
103 Left_Len - Bytes_Compared_As_Words,
104 Right_Len - Bytes_Compared_As_Words);
106 end Compare_Array_S8;
108 --------------------------------
109 -- Compare_Array_S8_Unaligned --
110 --------------------------------
112 function Compare_Array_S8_Unaligned
113 (Left : System.Address;
114 Right : System.Address;
116 Right_Len : Natural) return Integer
118 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
120 LeftP : constant Big_Bytes_Ptr := To_Big_Bytes (Left);
121 RightP : constant Big_Bytes_Ptr := To_Big_Bytes (Right);
124 for J in 0 .. Compare_Len - 1 loop
125 if LeftP (J) /= RightP (J) then
126 if LeftP (J) > RightP (J) then
134 if Left_Len = Right_Len then
136 elsif Left_Len > Right_Len then
141 end Compare_Array_S8_Unaligned;
143 end System.Compare_Array_Signed_8;