------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME LIBRARY COMPONENTS -- -- -- -- 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 -- -- -- -- B o d y -- -- -- -- Copyright (C) 2002-2009, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with System.Address_Operations; use System.Address_Operations; with Ada.Unchecked_Conversion; package body System.Compare_Array_Unsigned_16 is type Word is mod 2 ** 32; -- Used to process operands by words type Half is mod 2 ** 16; for Half'Size use 16; -- Used to process operands by half words type Uhalf is new Half; for Uhalf'Alignment use 1; -- Used to process operands when unaligned type WP is access Word; type HP is access Half; type UP is access Uhalf; function W is new Ada.Unchecked_Conversion (Address, WP); function H is new Ada.Unchecked_Conversion (Address, HP); function U is new Ada.Unchecked_Conversion (Address, UP); ----------------------- -- Compare_Array_U16 -- ----------------------- function Compare_Array_U16 (Left : System.Address; Right : System.Address; Left_Len : Natural; Right_Len : Natural) return Integer is Clen : Natural := Natural'Min (Left_Len, Right_Len); -- Number of elements left to compare L : Address := Left; R : Address := Right; -- Pointers to next elements to compare begin -- Go by words if possible if ModA (OrA (Left, Right), 4) = 0 then while Clen > 1 and then W (L).all = W (R).all loop Clen := Clen - 2; L := AddA (L, 4); R := AddA (R, 4); end loop; end if; -- Case of going by aligned half words if ModA (OrA (Left, Right), 2) = 0 then while Clen /= 0 loop if H (L).all /= H (R).all then if H (L).all > H (R).all then return +1; else return -1; end if; end if; Clen := Clen - 1; L := AddA (L, 2); R := AddA (R, 2); end loop; -- Case of going by unaligned half words else while Clen /= 0 loop if U (L).all /= U (R).all then if U (L).all > U (R).all then return +1; else return -1; end if; end if; Clen := Clen - 1; L := AddA (L, 2); R := AddA (R, 2); end loop; end if; -- Here if common section equal, result decided by lengths if Left_Len = Right_Len then return 0; elsif Left_Len > Right_Len then return +1; else return -1; end if; end Compare_Array_U16; end System.Compare_Array_Unsigned_16;