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Diffstat (limited to 'gcc-4.7/gcc/ada/g-mbdira.adb')
| -rw-r--r-- | gcc-4.7/gcc/ada/g-mbdira.adb | 282 |
1 files changed, 0 insertions, 282 deletions
diff --git a/gcc-4.7/gcc/ada/g-mbdira.adb b/gcc-4.7/gcc/ada/g-mbdira.adb deleted file mode 100644 index 44937f9d6..000000000 --- a/gcc-4.7/gcc/ada/g-mbdira.adb +++ /dev/null @@ -1,282 +0,0 @@ ------------------------------------------------------------------------------- --- -- --- GNAT RUN-TIME COMPONENTS -- --- -- --- G N A T . M B B S _ D I S C R E T E _ R A N D O M -- --- -- --- B o d y -- --- -- --- Copyright (C) 1992-2010, 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. -- --- -- ------------------------------------------------------------------------------- - -with Ada.Calendar; - -with Interfaces; use Interfaces; - -package body GNAT.MBBS_Discrete_Random is - - package Calendar renames Ada.Calendar; - - Fits_In_32_Bits : constant Boolean := - Rst'Size < 31 - or else (Rst'Size = 31 - and then Rst'Pos (Rst'First) < 0); - -- This is set True if we do not need more than 32 bits in the result. If - -- we need 64-bits, we will only use the meaningful 48 bits of any 64-bit - -- number generated, since if more than 48 bits are required, we split the - -- computation into two separate parts, since the algorithm does not behave - -- above 48 bits. - - -- The way this expression works is that obviously if the size is 31 bits, - -- it fits in 32 bits. In the 32-bit case, it fits in 32-bit signed if the - -- range has negative values. It is too conservative in the case that the - -- programmer has set a size greater than the default, e.g. a size of 33 - -- for an integer type with a range of 1..10, but an over-conservative - -- result is OK. The important thing is that the value is only True if - -- we know the result will fit in 32-bits signed. If the value is False - -- when it could be True, the behavior will be correct, just a bit less - -- efficient than it could have been in some unusual cases. - -- - -- One might assume that we could get a more accurate result by testing - -- the lower and upper bounds of the type Rst against the bounds of 32-bit - -- Integer. However, there is no easy way to do that. Why? Because in the - -- relatively rare case where this expression has to be evaluated at run - -- time rather than compile time (when the bounds are dynamic), we need a - -- type to use for the computation. But the possible range of upper bound - -- values for Rst (remembering the possibility of 64-bit modular types) is - -- from -2**63 to 2**64-1, and no run-time type has a big enough range. - - ----------------------- - -- Local Subprograms -- - ----------------------- - - function Square_Mod_N (X, N : Int) return Int; - pragma Inline (Square_Mod_N); - -- Computes X**2 mod N avoiding intermediate overflow - - ----------- - -- Image -- - ----------- - - function Image (Of_State : State) return String is - begin - return Int'Image (Of_State.X1) & - ',' & - Int'Image (Of_State.X2) & - ',' & - Int'Image (Of_State.Q); - end Image; - - ------------ - -- Random -- - ------------ - - function Random (Gen : Generator) return Rst is - S : State renames Gen.Writable.Self.Gen_State; - Temp : Int; - TF : Flt; - - begin - -- Check for flat range here, since we are typically run with checks - -- off, note that in practice, this condition will usually be static - -- so we will not actually generate any code for the normal case. - - if Rst'Last < Rst'First then - raise Constraint_Error; - end if; - - -- Continue with computation if non-flat range - - S.X1 := Square_Mod_N (S.X1, S.P); - S.X2 := Square_Mod_N (S.X2, S.Q); - Temp := S.X2 - S.X1; - - -- Following duplication is not an error, it is a loop unwinding! - - if Temp < 0 then - Temp := Temp + S.Q; - end if; - - if Temp < 0 then - Temp := Temp + S.Q; - end if; - - TF := Offs + (Flt (Temp) * Flt (S.P) + Flt (S.X1)) * S.Scl; - - -- Pathological, but there do exist cases where the rounding implicit - -- in calculating the scale factor will cause rounding to 'Last + 1. - -- In those cases, returning 'First results in the least bias. - - if TF >= Flt (Rst'Pos (Rst'Last)) + 0.5 then - return Rst'First; - - elsif not Fits_In_32_Bits then - return Rst'Val (Interfaces.Integer_64 (TF)); - - else - return Rst'Val (Int (TF)); - end if; - end Random; - - ----------- - -- Reset -- - ----------- - - procedure Reset (Gen : Generator; Initiator : Integer) is - S : State renames Gen.Writable.Self.Gen_State; - X1, X2 : Int; - - begin - X1 := 2 + Int (Initiator) mod (K1 - 3); - X2 := 2 + Int (Initiator) mod (K2 - 3); - - for J in 1 .. 5 loop - X1 := Square_Mod_N (X1, K1); - X2 := Square_Mod_N (X2, K2); - end loop; - - -- Eliminate effects of small Initiators - - S := - (X1 => X1, - X2 => X2, - P => K1, - Q => K2, - FP => K1F, - Scl => Scal); - end Reset; - - ----------- - -- Reset -- - ----------- - - procedure Reset (Gen : Generator) is - S : State renames Gen.Writable.Self.Gen_State; - Now : constant Calendar.Time := Calendar.Clock; - X1 : Int; - X2 : Int; - - begin - X1 := Int (Calendar.Year (Now)) * 12 * 31 + - Int (Calendar.Month (Now) * 31) + - Int (Calendar.Day (Now)); - - X2 := Int (Calendar.Seconds (Now) * Duration (1000.0)); - - X1 := 2 + X1 mod (K1 - 3); - X2 := 2 + X2 mod (K2 - 3); - - -- Eliminate visible effects of same day starts - - for J in 1 .. 5 loop - X1 := Square_Mod_N (X1, K1); - X2 := Square_Mod_N (X2, K2); - end loop; - - S := - (X1 => X1, - X2 => X2, - P => K1, - Q => K2, - FP => K1F, - Scl => Scal); - - end Reset; - - ----------- - -- Reset -- - ----------- - - procedure Reset (Gen : Generator; From_State : State) is - begin - Gen.Writable.Self.Gen_State := From_State; - end Reset; - - ---------- - -- Save -- - ---------- - - procedure Save (Gen : Generator; To_State : out State) is - begin - To_State := Gen.Gen_State; - end Save; - - ------------------ - -- Square_Mod_N -- - ------------------ - - function Square_Mod_N (X, N : Int) return Int is - begin - return Int ((Integer_64 (X) ** 2) mod (Integer_64 (N))); - end Square_Mod_N; - - ----------- - -- Value -- - ----------- - - function Value (Coded_State : String) return State is - Last : constant Natural := Coded_State'Last; - Start : Positive := Coded_State'First; - Stop : Positive := Coded_State'First; - Outs : State; - - begin - while Stop <= Last and then Coded_State (Stop) /= ',' loop - Stop := Stop + 1; - end loop; - - if Stop > Last then - raise Constraint_Error; - end if; - - Outs.X1 := Int'Value (Coded_State (Start .. Stop - 1)); - Start := Stop + 1; - - loop - Stop := Stop + 1; - exit when Stop > Last or else Coded_State (Stop) = ','; - end loop; - - if Stop > Last then - raise Constraint_Error; - end if; - - Outs.X2 := Int'Value (Coded_State (Start .. Stop - 1)); - Outs.Q := Int'Value (Coded_State (Stop + 1 .. Last)); - Outs.P := Outs.Q * 2 + 1; - Outs.FP := Flt (Outs.P); - Outs.Scl := (RstL - RstF + 1.0) / (Flt (Outs.P) * Flt (Outs.Q)); - - -- Now do *some* sanity checks - - if Outs.Q < 31 - or else Outs.X1 not in 2 .. Outs.P - 1 - or else Outs.X2 not in 2 .. Outs.Q - 1 - then - raise Constraint_Error; - end if; - - return Outs; - end Value; - -end GNAT.MBBS_Discrete_Random; |