IDSR_BUSY
if (idsr & IDSR_BUSY) {
} while (idsr & IDSR_BUSY);
busymask = IDSR_BUSY;
if (idsr & IDSR_BUSY) {
else if (idsr & IDSR_BUSY)
busymask = IDSR_BUSY;
busymask = IDSR_BUSY;
#define IDSR_BUSY_BIT(i) ((uint64_t)IDSR_BUSY << (2 * (i)))