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Diffstat (limited to 'gcc/ada/s-casi16.adb')
| -rw-r--r-- | gcc/ada/s-casi16.adb | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/gcc/ada/s-casi16.adb b/gcc/ada/s-casi16.adb new file mode 100644 index 00000000000..dc417e3884d --- /dev/null +++ b/gcc/ada/s-casi16.adb @@ -0,0 +1,137 @@ +------------------------------------------------------------------------------ +-- -- +-- GNU ADA RUNTIME LIBRARY COMPONENTS -- +-- -- +-- 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 -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 2002 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 2, 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. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING. If not, write -- +-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- +-- MA 02111-1307, USA. -- +-- -- +-- As a special exception, if other files instantiate generics from this -- +-- unit, or you link this unit with other files to produce an executable, -- +-- this unit does not by itself cause the resulting executable to be -- +-- covered by the GNU General Public License. This exception does not -- +-- however invalidate any other reasons why the executable file might be -- +-- covered by the GNU Public License. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Unchecked_Conversion; + +package body System.Compare_Array_Signed_16 is + + type Word is mod 2 ** 32; + -- Used to process operands by words + + type Half is range -(2 ** 15) .. (2 ** 15) - 1; + for Half'Size use 16; + -- Used to process operands by half words + + type Uhalf is record + H : Half; + end record; + pragma Pack (Uhalf); + 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 Unchecked_Conversion (Address, WP); + function H is new Unchecked_Conversion (Address, HP); + function U is new Unchecked_Conversion (Address, UP); + + ----------------------- + -- Compare_Array_S16 -- + ----------------------- + + function Compare_Array_S16 + (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 ((Left or Right) and (4 - 1)) = 0 then + while Clen > 1 + and then W (L).all = W (R).all + loop + Clen := Clen - 2; + L := L + 4; + R := R + 4; + end loop; + end if; + + -- Case of going by aligned half words + + if ((Left or Right) and (2 - 1)) = 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 := L + 2; + R := R + 2; + end loop; + + -- Case of going by unaligned half words + + else + while Clen /= 0 loop + if U (L).H /= U (R).H then + if U (L).H > U (R).H then + return +1; + else + return -1; + end if; + end if; + + Clen := Clen - 1; + L := L + 2; + R := 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_S16; + +end System.Compare_Array_Signed_16; |