| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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; |
