Mercurial > hg > CbC > CbC_gcc
comparison gcc/ada/libgnat/g-mbdira.ads @ 111:04ced10e8804
gcc 7
| author | kono |
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| date | Fri, 27 Oct 2017 22:46:09 +0900 |
| parents | |
| children | 84e7813d76e9 |
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| 68:561a7518be6b | 111:04ced10e8804 |
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| 1 ------------------------------------------------------------------------------ | |
| 2 -- -- | |
| 3 -- GNAT RUN-TIME COMPONENTS -- | |
| 4 -- -- | |
| 5 -- G N A T . M B B S _ D I S C R E T E _ R A N D O M -- | |
| 6 -- -- | |
| 7 -- S p e c -- | |
| 8 -- -- | |
| 9 -- Copyright (C) 1992-2017, Free Software Foundation, Inc. -- | |
| 10 -- -- | |
| 11 -- This specification is derived from the Ada Reference Manual for use with -- | |
| 12 -- GNAT. The copyright notice above, and the license provisions that follow -- | |
| 13 -- apply solely to the contents of the part following the private keyword. -- | |
| 14 -- -- | |
| 15 -- GNAT is free software; you can redistribute it and/or modify it under -- | |
| 16 -- terms of the GNU General Public License as published by the Free Soft- -- | |
| 17 -- ware Foundation; either version 3, or (at your option) any later ver- -- | |
| 18 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- | |
| 19 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
| 20 -- or FITNESS FOR A PARTICULAR PURPOSE. -- | |
| 21 -- -- | |
| 22 -- As a special exception under Section 7 of GPL version 3, you are granted -- | |
| 23 -- additional permissions described in the GCC Runtime Library Exception, -- | |
| 24 -- version 3.1, as published by the Free Software Foundation. -- | |
| 25 -- -- | |
| 26 -- You should have received a copy of the GNU General Public License and -- | |
| 27 -- a copy of the GCC Runtime Library Exception along with this program; -- | |
| 28 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- | |
| 29 -- <http://www.gnu.org/licenses/>. -- | |
| 30 -- -- | |
| 31 -- GNAT was originally developed by the GNAT team at New York University. -- | |
| 32 -- Extensive contributions were provided by Ada Core Technologies Inc. -- | |
| 33 -- -- | |
| 34 ------------------------------------------------------------------------------ | |
| 35 | |
| 36 -- The implementation used in this package was contributed by Robert | |
| 37 -- Eachus. It is based on the work of L. Blum, M. Blum, and M. Shub, SIAM | |
| 38 -- Journal of Computing, Vol 15. No 2, May 1986. The particular choices for P | |
| 39 -- and Q chosen here guarantee a period of 562,085,314,430,582 (about 2**49), | |
| 40 -- and the generated sequence has excellent randomness properties. For further | |
| 41 -- details, see the paper "Fast Generation of Trustworthy Random Numbers", by | |
| 42 -- Robert Eachus, which describes both the algorithm and the efficient | |
| 43 -- implementation approach used here. | |
| 44 | |
| 45 -- Formerly, this package was Ada.Numerics.Discrete_Random. It is retained | |
| 46 -- here in part to allow users to reconstruct number sequences generated | |
| 47 -- by previous versions. | |
| 48 | |
| 49 with Interfaces; | |
| 50 | |
| 51 generic | |
| 52 type Result_Subtype is (<>); | |
| 53 | |
| 54 package GNAT.MBBS_Discrete_Random is | |
| 55 | |
| 56 -- The algorithm used here is reliable from a required statistical point of | |
| 57 -- view only up to 48 bits. We try to behave reasonably in the case of | |
| 58 -- larger types, but we can't guarantee the required properties. So | |
| 59 -- generate a warning for these (slightly) dubious cases. | |
| 60 | |
| 61 pragma Compile_Time_Warning | |
| 62 (Result_Subtype'Size > 48, | |
| 63 "statistical properties not guaranteed for size > 48"); | |
| 64 | |
| 65 -- Basic facilities | |
| 66 | |
| 67 type Generator is limited private; | |
| 68 | |
| 69 function Random (Gen : Generator) return Result_Subtype; | |
| 70 | |
| 71 procedure Reset (Gen : Generator); | |
| 72 procedure Reset (Gen : Generator; Initiator : Integer); | |
| 73 | |
| 74 -- Advanced facilities | |
| 75 | |
| 76 type State is private; | |
| 77 | |
| 78 procedure Save (Gen : Generator; To_State : out State); | |
| 79 procedure Reset (Gen : Generator; From_State : State); | |
| 80 | |
| 81 Max_Image_Width : constant := 80; | |
| 82 | |
| 83 function Image (Of_State : State) return String; | |
| 84 function Value (Coded_State : String) return State; | |
| 85 | |
| 86 private | |
| 87 subtype Int is Interfaces.Integer_32; | |
| 88 subtype Rst is Result_Subtype; | |
| 89 | |
| 90 -- We prefer to use 14 digits for Flt, but some targets are more limited | |
| 91 | |
| 92 type Flt is digits Positive'Min (14, Long_Long_Float'Digits); | |
| 93 | |
| 94 RstF : constant Flt := Flt (Rst'Pos (Rst'First)); | |
| 95 RstL : constant Flt := Flt (Rst'Pos (Rst'Last)); | |
| 96 | |
| 97 Offs : constant Flt := RstF - 0.5; | |
| 98 | |
| 99 K1 : constant := 94_833_359; | |
| 100 K1F : constant := 94_833_359.0; | |
| 101 K2 : constant := 47_416_679; | |
| 102 K2F : constant := 47_416_679.0; | |
| 103 Scal : constant Flt := (RstL - RstF + 1.0) / (K1F * K2F); | |
| 104 | |
| 105 type State is record | |
| 106 X1 : Int := Int (2999 ** 2); | |
| 107 X2 : Int := Int (1439 ** 2); | |
| 108 P : Int := K1; | |
| 109 Q : Int := K2; | |
| 110 FP : Flt := K1F; | |
| 111 Scl : Flt := Scal; | |
| 112 end record; | |
| 113 | |
| 114 type Writable_Access (Self : access Generator) is limited null record; | |
| 115 -- Auxiliary type to make Generator a self-referential type | |
| 116 | |
| 117 type Generator is limited record | |
| 118 Writable : Writable_Access (Generator'Access); | |
| 119 -- This self reference allows functions to modify Generator arguments | |
| 120 Gen_State : State; | |
| 121 end record; | |
| 122 | |
| 123 end GNAT.MBBS_Discrete_Random; |