Beispiel #1
0
/*
 * Generate, and munge a 32bit number.
 */
unsigned int rand32(void)
{
	unsigned long r = 0;

	r = __rand32();

	if (rand_bool()) {
		unsigned int i;
		unsigned int rounds;

		/* mangle it. */
		rounds = rand() % 3;
		for (i = 0; i < rounds; i++) {
			if (rand_bool())
				r |= __rand32();
			else
				r ^= __rand32();
		}
	}

	/* Sometimes deduct it from INT_MAX */
	if (rand_bool())
		r = INT_MAX - r;

	/* Sometimes flip sign */
	if (rand_bool())
		r |= (1L << 31);

	/* we might get lucky if something is counting ints/longs etc. */
	if (rand() % 100 < 25) {
		int _div = 1 << rand_range(1, 4);	/* 2,4,8 or 16 */
		r /= _div;
	}

	/* limit the size */
	switch (rand() % 5) {
	case 0: r &= 0xff;
		break;
	case 1: r &= 0xffff;
		break;
	case 2: r &= PAGE_MASK;
		break;
	case 3: r &= 0xffffff;
		break;
	case 4:	// do nothing
		break;
	}

	return r;
}
Beispiel #2
0
unsigned int rand32(void)
{
	unsigned long r = 0;

	r = __rand32();

	if (rand_bool()) {
		unsigned int i;
		unsigned int rounds;

		/* mangle it. */
		rounds = rand() % 3;
		for (i = 0; i < rounds; i++) {
			switch (rand_bool()) {
			case 0: r |= __rand32();
				break;
			case 1: r ^= __rand32();
				break;
			default:
				break;
			}
		}
	}

	if (rand_bool())
		r = INT_MAX - r;

	if (rand_bool())
		r |= (1L << 31);

	/* limit the size */
	switch (rand() % 4) {
	case 0: r &= 0xff;
		break;
	case 1: r &= 0xffff;
		break;
	case 2: r &= 0xffffff;
		break;
	default:
		break;
	}

	return r;
}
Beispiel #3
0
Datei: rand.c Projekt: chjs/fio
static void __init_rand32(struct taus88_state *state, unsigned int seed)
{
    int cranks = 6;

#define LCG(x, seed)  ((x) * 69069 ^ (seed))

    state->s1 = __seed(LCG((2^31) + (2^17) + (2^7), seed), 1);
    state->s2 = __seed(LCG(state->s1, seed), 7);
    state->s3 = __seed(LCG(state->s2, seed), 15);

    while (cranks--)
        __rand32(state);
}