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change check_word to check_byte, 256 values is fine... remove overkill NULL check

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This commit is contained in:
graham sanderson 2023-01-25 18:38:53 -06:00
parent b9953fa3b7
commit a6c593062d
1 changed files with 6 additions and 8 deletions
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14
src/rp2_common/pico_rand/rand.c
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@ -252,9 +252,9 @@ uint64_t get_rand_64(void) {
initialise_rand();
}
static volatile uint16_t check_word;
static volatile uint16_t check_byte;
rng_128_t local_rng_state = rng_state;
uint16_t local_check_word = check_word;
uint8_t local_check_byte = check_byte;
// Modify PRNG state with the two run-time entropy sources,
// hashed to reduce correlation with previous modifications.
uint which = 0;
@ -278,7 +278,7 @@ uint64_t get_rand_64(void) {
spin_lock_t *lock = spin_lock_instance(PICO_SPINLOCK_ID_RAND);
uint32_t save = spin_lock_blocking(lock);
if (local_check_word != check_word) {
if (local_check_byte != check_byte) {
// someone got a random number in the interim, so mix it in
local_rng_state.r[0] ^= rng_state.r[0];
local_rng_state.r[1] ^= rng_state.r[1];
@ -287,17 +287,15 @@ uint64_t get_rand_64(void) {
// Note: This also "churns" the 128-bit state for next time.
uint64_t rand64 = xoroshiro128ss(&local_rng_state);
rng_state = local_rng_state;
check_word++;
check_byte++;
spin_unlock(lock, save);
return rand64;
}
void get_rand_128(rng_128_t *ptr128) {
if (ptr128 != NULL) {
ptr128->r[0] = get_rand_64();
ptr128->r[1] = get_rand_64();
}
ptr128->r[0] = get_rand_64();
ptr128->r[1] = get_rand_64();
}
uint32_t get_rand_32(void) {