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git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1011 bbd45198-f89e-11dd-88c7-29a3b14d5316
36 lines
600 B
C
36 lines
600 B
C
#include <stdlib.h>
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#include <sys/types.h>
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static unsigned int seed=1;
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/* Knuth's TAOCP section 3.6 */
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#define M ((1U<<31) -1)
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#define A 48271
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#define Q 44488 // M/A
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#define R 3399 // M%A; R < Q !!!
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// FIXME: ISO C/SuS want a longer period
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int rand_r(unsigned int* seed)
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{ int32_t X;
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X = *seed;
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X = A*(X%Q) - R * (int32_t) (X/Q);
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if (X < 0)
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X += M;
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*seed = X;
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return X;
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}
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int rand(void) {
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return rand_r(&seed);
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}
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void srand(unsigned int i)
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{
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seed=i;
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}
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int random(void) __attribute__((alias("rand")));
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void srandom(unsigned int i) __attribute__((alias("srand")));
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