ACPI_USEC_PER_MSEC
usleep (10 * ACPI_USEC_PER_MSEC); /* ten milliseconds */
usleep (ACPI_USEC_PER_MSEC); /* one millisecond */
usleep ((milliseconds % ACPI_MSEC_PER_SEC) * ACPI_USEC_PER_MSEC);
if ((MicroSeconds - (MilliSeconds * ACPI_USEC_PER_MSEC)) >= 500)
AcpiOsStall (ACPI_USEC_PER_MSEC);
AcpiOsStall (ACPI_USEC_PER_MSEC);