85 lines
4.6 KiB
Ada
85 lines
4.6 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . A R I T H _ 6 4 --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This unit provides software routines for doing arithmetic on 64-bit
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-- signed integer values in cases where either overflow checking is
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-- required, or intermediate results are longer than 64 bits.
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pragma Restrictions (No_Elaboration_Code);
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-- Allow direct call from gigi generated code
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with Interfaces;
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package System.Arith_64 is
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pragma Pure;
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subtype Int64 is Interfaces.Integer_64;
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function Add_With_Ovflo_Check (X, Y : Int64) return Int64;
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-- Raises Constraint_Error if sum of operands overflows 64 bits,
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-- otherwise returns the 64-bit signed integer sum.
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function Subtract_With_Ovflo_Check (X, Y : Int64) return Int64;
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-- Raises Constraint_Error if difference of operands overflows 64
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-- bits, otherwise returns the 64-bit signed integer difference.
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function Multiply_With_Ovflo_Check (X, Y : Int64) return Int64;
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pragma Export (C, Multiply_With_Ovflo_Check, "__gnat_mulv64");
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-- Raises Constraint_Error if product of operands overflows 64
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-- bits, otherwise returns the 64-bit signed integer product.
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-- GIGI may also call this routine directly.
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procedure Scaled_Divide
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(X, Y, Z : Int64;
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Q, R : out Int64;
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Round : Boolean);
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-- Performs the division of (X * Y) / Z, storing the quotient in Q
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-- and the remainder in R. Constraint_Error is raised if Z is zero,
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-- or if the quotient does not fit in 64-bits. Round indicates if
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-- the result should be rounded. If Round is False, then Q, R are
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-- the normal quotient and remainder from a truncating division.
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-- If Round is True, then Q is the rounded quotient. The remainder
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-- R is not affected by the setting of the Round flag.
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procedure Double_Divide
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(X, Y, Z : Int64;
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Q, R : out Int64;
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Round : Boolean);
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-- Performs the division X / (Y * Z), storing the quotient in Q and
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-- the remainder in R. Constraint_Error is raised if Y or Z is zero,
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-- or if the quotient does not fit in 64-bits. Round indicates if the
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-- result should be rounded. If Round is False, then Q, R are the normal
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-- quotient and remainder from a truncating division. If Round is True,
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-- then Q is the rounded quotient. The remainder R is not affected by the
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-- setting of the Round flag.
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end System.Arith_64;
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