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/** @file
*
* Random number generation
*
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdlib.h>
#include <gpxe/timer.h>
static int32_t rnd_seed = 0;
/**
* Seed the pseudo-random number generator
*
* @v seed Seed value
*/
void srandom ( unsigned int seed ) {
rnd_seed = seed;
}
/**
* Generate a pseudo-random number between 0 and 2147483647L or 2147483562?
*
* @ret rand Pseudo-random number
*/
long int random ( void ) {
int32_t q;
if ( ! rnd_seed ) /* Initialize linear congruential generator */
srandom ( currticks() );
/* simplified version of the LCG given in Bruce Schneier's
"Applied Cryptography" */
q = ( rnd_seed / 53668 );
rnd_seed = ( 40014 * ( rnd_seed - 53668 * q ) - 12211 * q );
if ( rnd_seed < 0 )
rnd_seed += 2147483563L;
return rnd_seed;
}
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