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int persist(uint8_t slot, int64_t value);
int64_t retrieve(uint8_t slot);

double cool_val = 42.43;
int64_t* tmp = (int64_t*)&cool_val;
persist(0, *tmp);

int64_t tmp = retrieve(0);
double cool_val = *(double*)&tmp;

double cool_val = 42.43;
int64_t tmp = 0;
memcpy(&tmp, &cool_val, sizeof(tmp));
persist(0, tmp);

int64_t tmp = retrieve(0);
double cool_val = 0.0;
memcpy(&cool_val, &tmp, sizeof(cool_val));

double cool_val = 42.43;
persist(0, std::abc_defg<int64_t>(cool_val));

double cool_val = std::abc_defg<double>(retrieve(0));

double cool_val = 42.43;
persist(0, std::bit_cast<int64_t>(cool_val));

double cool_val = std::bit_cast<double>(retrieve(0));