ACPI_TIMER24_MASK
counter = _acpi_get_timer() & (uint32_t)ACPI_TIMER24_MASK;
if (counter < (last_counter & ACPI_TIMER24_MASK))
counter &= (uint32_t)ACPI_TIMER24_MASK;
if (counter < (last_counter & ACPI_TIMER24_MASK))
#define ACPI_TIMER24_HIBITS (~ACPI_TIMER24_MASK)