How do BLE IoT devices usually generate their private MAC addresses?

Are there any common ways for a BLE IoT device to generate its resolvable/non-resolvable private device addresses?

For example, it seems that in BR/EDR (classic Bluetooth) the spec demands the use of FIPS PRNGs, but I don't see the recommended/compulsory/popular ways to generate the 24-bit prand in resolvable private device addresses on Bluetooth Low Energy peripheral devices.

I wonder if resource constraints would stop IoT devices from using FIPS PRNGs. The results I found so far on MAC randomization are all about BLE on mobile devices...