libdieharder-dev 3.31.1-7build1 / usr / include / dieharder / rgb_persist.h

/*
 * diehard_rgb_persist test header.  This test needs to just go
 * away...
 */

/*
 * function prototype
 */
typedef struct {
  unsigned int nbits;
  unsigned int and_mask;
  unsigned int cumulative_mask;
} Rgb_Persist;
int rgb_persist(Test **test, Rgb_Persist *persist);

static Dtest rgb_persist_dtest __attribute__((unused)) = {
  "RGB Bit Persistence Test",
  "rgb_persist", 
  "\n\
#========================================================================\n\
#                   RGB Bit Persistence Test\n\
# This test generates 256 sequential samples of an random unsigned\n\
# integer from the given rng.  Successive integers are logically\n\
# processed to extract a mask with 1's whereever bits do not\n\
# change.  Since bits will NOT change when filling e.g. unsigned\n\
# ints with 16 bit ints, this mask logically &'d with the maximum\n\
# random number returned by the rng.  All the remaining 1's in the\n\
# resulting mask are therefore significant -- they represent bits\n\
# that never change over the length of the test.  These bits are\n\
# very likely the reason that certain rng's fail the monobit\n\
# test -- extra persistent e.g. 1's or 0's inevitably bias the\n\
# total bitcount.  In many cases the particular bits repeated\n\
# appear to depend on the seed.  If the -i flag is given, the\n\
# entire test is repeated with the rng reseeded to generate a mask\n\
# and the extracted mask cumulated to show all the possible bit\n\
# positions that might be repeated for different seeds.\n\
",
  1,
  256,
  1,
  rgb_persist,
  0
};

unsigned int *rgb_persist_rand_uint;