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 _ U N S I G N E D _ 1 6 --
9 -- Copyright (C) 2002-2009, 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 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. --
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. --
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/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 with System.Address_Operations; use System.Address_Operations;
34 with Ada.Unchecked_Conversion;
36 package body System.Compare_Array_Unsigned_16 is
38 type Word is mod 2 ** 32;
39 -- Used to process operands by words
41 type Half is mod 2 ** 16;
43 -- Used to process operands by half words
45 type Uhalf is new Half;
46 for Uhalf'Alignment use 1;
47 -- Used to process operands when unaligned
49 type WP is access Word;
50 type HP is access Half;
51 type UP is access Uhalf;
53 function W is new Ada.Unchecked_Conversion (Address, WP);
54 function H is new Ada.Unchecked_Conversion (Address, HP);
55 function U is new Ada.Unchecked_Conversion (Address, UP);
57 -----------------------
58 -- Compare_Array_U16 --
59 -----------------------
61 function Compare_Array_U16
62 (Left : System.Address;
63 Right : System.Address;
65 Right_Len : Natural) return Integer
67 Clen : Natural := Natural'Min (Left_Len, Right_Len);
68 -- Number of elements left to compare
72 -- Pointers to next elements to compare
75 -- Go by words if possible
77 if ModA (OrA (Left, Right), 4) = 0 then
79 and then W (L).all = W (R).all
87 -- Case of going by aligned half words
89 if ModA (OrA (Left, Right), 2) = 0 then
91 if H (L).all /= H (R).all then
92 if H (L).all > H (R).all then
104 -- Case of going by unaligned half words
108 if U (L).all /= U (R).all then
109 if U (L).all > U (R).all then
122 -- Here if common section equal, result decided by lengths
124 if Left_Len = Right_Len then
126 elsif Left_Len > Right_Len then
131 end Compare_Array_U16;
133 end System.Compare_Array_Unsigned_16;