--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ada/libgnat/s-arit64.ads	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,84 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT COMPILER COMPONENTS                         --
+--                                                                          --
+--                      S Y S T E M . A R I T H _ 6 4                       --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--          Copyright (C) 1992-2017, 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    --
+-- <http://www.gnu.org/licenses/>.                                          --
+--                                                                          --
+-- GNAT was originally developed  by the GNAT team at  New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc.      --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  This unit provides software routines for doing arithmetic on 64-bit
+--  signed integer values in cases where either overflow checking is
+--  required, or intermediate results are longer than 64 bits.
+
+pragma Restrictions (No_Elaboration_Code);
+--  Allow direct call from gigi generated code
+
+with Interfaces;
+
+package System.Arith_64 is
+   pragma Pure;
+
+   subtype Int64 is Interfaces.Integer_64;
+
+   function Add_With_Ovflo_Check (X, Y : Int64) return Int64;
+   --  Raises Constraint_Error if sum of operands overflows 64 bits,
+   --  otherwise returns the 64-bit signed integer sum.
+
+   function Subtract_With_Ovflo_Check (X, Y : Int64) return Int64;
+   --  Raises Constraint_Error if difference of operands overflows 64
+   --  bits, otherwise returns the 64-bit signed integer difference.
+
+   function Multiply_With_Ovflo_Check (X, Y : Int64) return Int64;
+   pragma Export (C, Multiply_With_Ovflo_Check, "__gnat_mulv64");
+   --  Raises Constraint_Error if product of operands overflows 64
+   --  bits, otherwise returns the 64-bit signed integer product.
+   --  GIGI may also call this routine directly.
+
+   procedure Scaled_Divide
+     (X, Y, Z : Int64;
+      Q, R    : out Int64;
+      Round   : Boolean);
+   --  Performs the division of (X * Y) / Z, storing the quotient in Q
+   --  and the remainder in R. Constraint_Error is raised if Z is zero,
+   --  or if the quotient does not fit in 64-bits. Round indicates if
+   --  the result should be rounded. If Round is False, then Q, R are
+   --  the normal quotient and remainder from a truncating division.
+   --  If Round is True, then Q is the rounded quotient. The remainder
+   --  R is not affected by the setting of the Round flag.
+
+   procedure Double_Divide
+     (X, Y, Z : Int64;
+      Q, R    : out Int64;
+      Round   : Boolean);
+   --  Performs the division X / (Y * Z), storing the quotient in Q and
+   --  the remainder in R. Constraint_Error is raised if Y or Z is zero,
+   --  or if the quotient does not fit in 64-bits. Round indicates if the
+   --  result should be rounded. If Round is False, then Q, R are the normal
+   --  quotient and remainder from a truncating division. If Round is True,
+   --  then Q is the rounded quotient. The remainder R is not affected by the
+   --  setting of the Round flag.
+
+end System.Arith_64;