| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . A R I T H _ 6 4 -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1994,1995,1996 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. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- 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. |
| |
| with Interfaces; |
| |
| package System.Arith_64 is |
| pragma Pure (Arith_64); |
| |
| 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; |
| -- Raises Constraint_Error if product of operands overflows 64 |
| -- bits, otherwise returns the 64-bit signed integer difference. |
| |
| 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. |
| -- 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. The |
| -- result is known to be in range except for the noted possibility of |
| -- Y or Z being zero, so no other overflow checks are required. |
| |
| end System.Arith_64; |
