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mt_prng                 1  -- Ada implementation of the Mersenne Twister Pseudo-Random number generator
mt_prng                 2  -- S.MG, 2018
mt_prng                 3 
mt_prng                 4 with Interfaces; use Interfaces;
mt_prng                 5 
mt_prng                 6 package MT is
mt_prng                 7   -- Interfaces.Unsigned_32 in GNAT is mod 2**32 and has bitwise shifts defined
mt_prng                 8   subtype U32 is Interfaces.Unsigned_32;
mt_prng                 9 
mt_prng                10   -- period parameters
mt_prng                11   N          : constant := 624;
mt_prng                12   M          : constant := 397;
mt_prng                13   MATRIX_MASK: constant U32 := 16#9908_b0df#;
mt_prng                14   UPPER_MASK : constant U32 := 16#8000_0000#;
mt_prng                15   LOWER_MASK : constant U32 := 16#7fff_ffff#;
mt_prng                16 
mt_prng                17   -- array type for storing the state vector of the generator
mt_prng                18   type State_Type is Array( 0 .. N-1 ) of U32;
mt_prng                19 
mt_prng                20   -- array type for initialization by array - change key len here if needed
mt_prng                21   KEY_LEN    : constant := 4;
mt_prng                22   type Init_Array_Type is Array( 0 .. KEY_LEN - 1 ) of U32;
mt_prng                23 
mt_prng                24   -- exception raised by a call to generator before initializing it
mt_prng                25   No_Init_Exception : exception;
mt_prng                26 
mt_prng                27   -- initialize the generator with a seed (number)
mt_prng                28   procedure Init_Genrand(Seed : in U32);
mt_prng                29 
mt_prng                30   -- initialize the generator with array of 8-octets elements
mt_prng                31   procedure Init_Genrand(Seed : in Init_Array_Type);
mt_prng                32 
mt_prng                33   -- generate the next pseudo-random 32 bits number in the sequence
mt_prng                34   function Gen_U32 return U32;
mt_prng                35 
mt_prng                36   -- for testing
mt_prng                37   function Get_State return State_Type;
mt_prng                38 
mt_prng                39   -- internals of the generator, NOT for direct access
mt_prng                40 private
mt_prng                41   -- actual state of the generator
mt_prng                42   State      : State_Type;
mt_prng                43 
mt_prng                44   -- flag for generator routine
mt_prng                45   Mti_Flag : U32 := N + 1;  -- default value -> state(N) is not initialised
mt_prng                46 
mt_prng                47 end MT;