30 lines
789 B
C++
30 lines
789 B
C++
#include <Arduino.h>
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#include "maths.h"
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//Generates a random number from 1 to 100 (inclusive).
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//The initial seed used is always based on micros(), though this is unlikely to cause an issue as the first run is nearly random itself
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//Function requires 4 bytes to store state and seed, but operates very quickly (around 4uS per call)
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static uint8_t a, x, y, z;
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uint8_t random1to100()
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{
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//Check if this is the first time being run. If so, seed the random number generator with micros()
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if( (a == 0U) && (x == 0U) && (y == 0U) && (z == 0U) )
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{
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x = micros() >> 24U;
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y = micros() >> 16U;
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z = micros() >> 8U;
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a = micros();
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}
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do
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{
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unsigned char t = x ^ (x << 4);
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x=y;
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y=z;
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z=a;
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a = z ^ t ^ ( z >> 1) ^ (t << 1);
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}
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while(a >= 100U);
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return (a+1U);
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}
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