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 _ 16 --
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_16 is
40 type Word is mod 2 ** 32;
41 -- Used to process operands by words
43 type Half is range -(2 ** 15) .. (2 ** 15) - 1;
45 -- Used to process operands by half words
51 for Uhalf'Alignment use 1;
52 -- Used to process operands when unaligned
54 type WP is access Word;
55 type HP is access Half;
56 type UP is access Uhalf;
58 function W is new Ada.Unchecked_Conversion (Address, WP);
59 function H is new Ada.Unchecked_Conversion (Address, HP);
60 function U is new Ada.Unchecked_Conversion (Address, UP);
62 -----------------------
63 -- Compare_Array_S16 --
64 -----------------------
66 function Compare_Array_S16
67 (Left : System.Address;
68 Right : System.Address;
70 Right_Len : Natural) return Integer
72 Clen : Natural := Natural'Min (Left_Len, Right_Len);
73 -- Number of elements left to compare
77 -- Pointers to next elements to compare
80 -- Go by words if possible
82 if ModA (OrA (Left, Right), 4) = 0 then
84 and then W (L).all = W (R).all
92 -- Case of going by aligned half words
94 if ModA (OrA (Left, Right), 2) = 0 then
96 if H (L).all /= H (R).all then
97 if H (L).all > H (R).all then
109 -- Case of going by unaligned half words
113 if U (L).H /= U (R).H then
114 if U (L).H > U (R).H then
127 -- Here if common section equal, result decided by lengths
129 if Left_Len = Right_Len then
131 elsif Left_Len > Right_Len then
136 end Compare_Array_S16;
138 end System.Compare_Array_Signed_16;