------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S Y S T E M . A R I T H _ D O U B L E -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2020, 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. -- -- -- ------------------------------------------------------------------------------ -- This package provides software routines for doing arithmetic on "double" -- signed integer values in cases where either overflow checking is required, -- or intermediate results are longer than the result type. generic type Double_Int is range <>; type Double_Uns is mod <>; type Single_Uns is mod <>; with function Shift_Left (A : Double_Uns; B : Natural) return Double_Uns is <>; with function Shift_Right (A : Double_Uns; B : Natural) return Double_Uns is <>; with function Shift_Left (A : Single_Uns; B : Natural) return Single_Uns is <>; package System.Arith_Double is pragma Pure; function Add_With_Ovflo_Check (X, Y : Double_Int) return Double_Int; -- Raises Constraint_Error if sum of operands overflows Double_Int, -- otherwise returns the signed integer sum. function Subtract_With_Ovflo_Check (X, Y : Double_Int) return Double_Int; -- Raises Constraint_Error if difference of operands overflows Double_Int, -- otherwise returns the signed integer difference. function Multiply_With_Ovflo_Check (X, Y : Double_Int) return Double_Int; pragma Convention (C, Multiply_With_Ovflo_Check); -- Raises Constraint_Error if product of operands overflows Double_Int, -- otherwise returns the signed integer product. Gigi may also call this -- routine directly. procedure Scaled_Divide (X, Y, Z : Double_Int; Q, R : out Double_Int; 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 Double_Int. 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 : Double_Int; Q, R : out Double_Int; 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 Double_Int. 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_Double;