------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . S H A R E D _ B I G N U M S --
-- --
-- S p e c --
-- --
-- Copyright (C) 2012-2023, 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 package provides declarations shared across all instantiations of
-- System.Generic_Bignums.
with Ada.Unchecked_Conversion;
with Interfaces;
package System.Shared_Bignums is
pragma Preelaborate;
pragma Assert (Long_Long_Integer'Size = 64);
-- This package assumes that Long_Long_Integer size is 64 bit (i.e. that it
-- has a range of -2**63 to 2**63-1). The front end ensures that the mode
-- ELIMINATED is not allowed for overflow checking if this is not the case.
subtype Length is Natural range 0 .. 2 ** 23 - 1;
-- Represent number of words in Digit_Vector
Base : constant := 2 ** 32;
-- Digit vectors use this base
subtype SD is Interfaces.Unsigned_32;
-- Single length digit
type Digit_Vector is array (Length range <>) of SD;
-- Represent digits of a number (most significant digit first)
type Bignum_Data (Len : Length) is record
Neg : Boolean;
-- Set if value is negative, never set for zero
D : Digit_Vector (1 .. Len);
-- Digits of number, most significant first, represented in base
-- 2**Base. No leading zeroes are stored, and the value of zero is
-- represented using an empty vector for D.
end record;
for Bignum_Data use record
Len at 0 range 0 .. 23;
Neg at 3 range 0 .. 7;
end record;
type Bignum is access all Bignum_Data;
function To_Bignum is new Ada.Unchecked_Conversion (System.Address, Bignum);
function To_Address is new
Ada.Unchecked_Conversion (Bignum, System.Address);
end System.Shared_Bignums;