------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- G N A T . M B B S _ F L O A T _ R A N D O M -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2024, Free Software Foundation, Inc. -- -- -- -- This specification is derived from the Ada Reference Manual for use with -- -- GNAT. The copyright notice above, and the license provisions that follow -- -- apply solely to the contents of the part following the private keyword. -- -- -- -- 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. -- -- -- ------------------------------------------------------------------------------ -- The implementation used in this package was contributed by -- Robert Eachus. It is based on the work of L. Blum, M. Blum, and -- M. Shub, SIAM Journal of Computing, Vol 15. No 2, May 1986. The -- particular choices for P and Q chosen here guarantee a period of -- 562,085,314,430,582 (about 2**49), and the generated sequence has -- excellent randomness properties. For further details, see the -- paper "Fast Generation of Trustworthy Random Numbers", by Robert -- Eachus, which describes both the algorithm and the efficient -- implementation approach used here. -- Formerly, this package was Ada.Numerics.Float_Random. It is retained -- here in part to allow users to reconstruct number sequences generated -- by previous versions. with Interfaces; package GNAT.MBBS_Float_Random is -- Basic facilities type Generator is limited private; subtype Uniformly_Distributed is Float range 0.0 .. 1.0; function Random (Gen : Generator) return Uniformly_Distributed; procedure Reset (Gen : Generator); procedure Reset (Gen : Generator; Initiator : Integer); -- Advanced facilities type State is private; procedure Save (Gen : Generator; To_State : out State); procedure Reset (Gen : Generator; From_State : State); Max_Image_Width : constant := 80; function Image (Of_State : State) return String; function Value (Coded_State : String) return State; private type Int is new Interfaces.Integer_32; -- We prefer to use 14 digits for Flt, but some targets are more limited type Flt is digits Positive'Min (14, Long_Long_Float'Digits); K1 : constant := 94_833_359; K1F : constant := 94_833_359.0; K2 : constant := 47_416_679; K2F : constant := 47_416_679.0; Scal : constant := 1.0 / (K1F * K2F); type State is record X1 : Int := 2999 ** 2; -- Square mod p X2 : Int := 1439 ** 2; -- Square mod q P : Int := K1; Q : Int := K2; X : Int := 1; Scl : Flt := Scal; end record; type Generator is limited record Gen_State : State; end record; end GNAT.MBBS_Float_Random;