mips_sys

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/* MIPS I system
 * Copyright 2011-2012 Stefan Schuermans <stefan@blinkenarea.org>
 * Copyleft GNU public license V2 or later
 *          http://www.gnu.org/copyleft/gpl.html
 */
#include "random.h"
// FIXME: this random number generator is most likely not very good
/// state of the linear feedback shift register (LFSR)
static unsigned long random_lfsr = 1;
/// step LFSR
static void random_step(void)
{
  random_lfsr = (random_lfsr >> 1) ^ (-(random_lfsr & 1U) & 0xD0000001U);
}
/**
 * @brief provide entropy
 * @param[in] ptr pointer to buffer containing entropy
 * @param[in] sz size of buffer
 */
void random_provide_entropy(const void *ptr, unsigned int sz)
{
  const unsigned char *src = ptr;
  unsigned char val;
  unsigned int bit;
  for ( ; sz > 0; --sz) {
    val = *src++;
    for (bit = 0; bit < 8; ++bit) {
      if (val & 1)
        random_step();
      val >>= 1;
    }
  }
}
/**
 * @brief get random data
 * @param[in] ptr pointer to buffer to fill with random data
 * @param[in] sz size of buffer to fill
 */
void random_get_data(void *ptr, unsigned int sz)
{
  unsigned char *dest = ptr;
  unsigned char val;
  unsigned int bit;
 
 
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