1------------------------------------------------------------------------------ 2-- -- 3-- GNU ADA RUNTIME LIBRARY COMPONENTS -- 4-- -- 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 -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2002 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 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. -- 21-- -- 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. -- 28-- -- 29-- GNAT was originally developed by the GNAT team at New York University. -- 30-- Extensive contributions were provided by Ada Core Technologies Inc. -- 31-- -- 32------------------------------------------------------------------------------ 33 34with Unchecked_Conversion; 35 36package body System.Compare_Array_Signed_8 is 37 38 type Word is mod 2 ** 32; 39 -- Used to process operands by words 40 41 type Big_Words is array (Natural) of Word; 42 type Big_Words_Ptr is access Big_Words; 43 -- Array type used to access by words 44 45 type Byte is range -128 .. +127; 46 for Byte'Size use 8; 47 -- Used to process operands by bytes 48 49 type Big_Bytes is array (Natural) of Byte; 50 type Big_Bytes_Ptr is access Big_Bytes; 51 -- Array type used to access by bytes 52 53 function To_Big_Words is new 54 Unchecked_Conversion (System.Address, Big_Words_Ptr); 55 56 function To_Big_Bytes is new 57 Unchecked_Conversion (System.Address, Big_Bytes_Ptr); 58 59 ---------------------- 60 -- Compare_Array_S8 -- 61 ---------------------- 62 63 function Compare_Array_S8 64 (Left : System.Address; 65 Right : System.Address; 66 Left_Len : Natural; 67 Right_Len : Natural) 68 return Integer 69 is 70 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len); 71 72 begin 73 -- If operands are non-aligned, or length is too short, go by bytes 74 75 if (((Left or Right) and 2#11#) /= 0) or else Compare_Len < 4 then 76 return Compare_Array_S8_Unaligned (Left, Right, Left_Len, Right_Len); 77 end if; 78 79 -- Here we can go by words 80 81 declare 82 LeftP : constant Big_Words_Ptr := To_Big_Words (Left); 83 RightP : constant Big_Words_Ptr := To_Big_Words (Right); 84 Clen4 : constant Natural := Compare_Len / 4 - 1; 85 Clen4F : constant Natural := Clen4 * 4; 86 87 begin 88 for J in 0 .. Clen4 loop 89 if LeftP (J) /= RightP (J) then 90 return Compare_Array_S8_Unaligned 91 (Left + Address (4 * J), 92 Right + Address (4 * J), 93 4, 4); 94 end if; 95 end loop; 96 97 return Compare_Array_S8_Unaligned 98 (Left + Address (Clen4F), 99 Right + Address (Clen4F), 100 Left_Len - Clen4F, 101 Right_Len - Clen4F); 102 end; 103 end Compare_Array_S8; 104 105 -------------------------------- 106 -- Compare_Array_S8_Unaligned -- 107 -------------------------------- 108 109 function Compare_Array_S8_Unaligned 110 (Left : System.Address; 111 Right : System.Address; 112 Left_Len : Natural; 113 Right_Len : Natural) 114 return Integer 115 is 116 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len); 117 118 LeftP : constant Big_Bytes_Ptr := To_Big_Bytes (Left); 119 RightP : constant Big_Bytes_Ptr := To_Big_Bytes (Right); 120 121 begin 122 for J in 0 .. Compare_Len - 1 loop 123 if LeftP (J) /= RightP (J) then 124 if LeftP (J) > RightP (J) then 125 return +1; 126 else 127 return -1; 128 end if; 129 end if; 130 end loop; 131 132 if Left_Len = Right_Len then 133 return 0; 134 elsif Left_Len > Right_Len then 135 return +1; 136 else 137 return -1; 138 end if; 139 end Compare_Array_S8_Unaligned; 140 141end System.Compare_Array_Signed_8; 142