[elektro] Véletlen az álvéletlennel

[Horvath Janos]

Ez a híres négyzet-közép-összeg...valami rémlik, ha az.
Az eredeti felállásban nekem olyan álvéletlenre volt szükségem,
ami garantálja a ciklikusságot 12-14-16-biten, de véletlen.
Ezt azért elteszem, köszi!
JAni

> //X ABC Algorithm Random Number Generator for 8-Bit Devices:
> //This is a small PRNG, experimentally verified to have at least a 50
> million byte period
> //by generating 50 million bytes and observing that there were no
> overapping sequences and repeats.
> //This generator passes serial correlation, entropy , Monte Carlo Pi value,
> arithmetic mean,
> //And many other statistical tests. This generator may have a period of up
> to 2^32, but this has
> //not been verified.
> //
> // By XORing 3 bytes into the a,b, and c registers, you can add in entropy
> from
> //an external source easily.
> //
> //This generator is free to use, but is not suitable for cryptography due
> to its short period(by //cryptographic standards) and simple construction.
> No attempt was made to make this generator
> // suitable for cryptographic use.
> //
> //Due to the use of a constant counter, the generator should be resistant
> to latching up.
> //A significant performance gain is had in that the x variable is nly ever
> incremented.
> //
> //Only 4 bytes of ram are needed for the internal state, and generating a
> byte requires 3 XORs , //2 ADDs, one bit shift right , and one increment.
> Difficult or slow operations like multiply, etc
> //were avoided for maximum speed on ultra low power devices.
>
>
> init_rng(s1,s2,s3) //Can also be used to seed the rng with more entropy
> during use.
> {
> //XOR new entropy into key state
> a ^=s1;
> b ^=s2;
> c ^=s3;
>
> x++;
> a = (a^c^x);
> b = (b+a);
> c = (c+(b>>1)^a);
> }
>
> unsigned char randomize()
> {
> x++;               //x is incremented every round and is not affected by
> any other variable
> a = (a^c^x);       //note the mix of addition and XOR
> b = (b+a);         //And the use of very few instructions
> c = (c+(b>>1)^a);  //the right shift is to ensure that high-order bits from
> b can affect
> return(c)          //low order bits of other variables
> }
>
> 2016. március 14. 21:09 Horvath Janos írta, <winnerbt at fibermail.hu>:
>
>> Sziasztok!
>> Random módon beleszaladtam egy álvéletlen problémába.
>> Van olyan uC amiben HW módon van a hétköznapi
>> shiftregiszteres+visszacsatolásos álvéletlen generátor?
>> Persze egy komparátor nem ártana még mellé.
>> A kimenet analóg lenne a végén.
>> (O.k. SW-ből meg tudom csinálni, de az lassú.)
>> JAni
>> 21:08
>>
>> -----------------------------------------
>>           elektro[-flame|-etc]
>>
>
>
>