On Tue, Apr 18, 2023 at 12:29:40PM -0500, Dinh Nguyen wrote: > On 4/17/2023 4:51 PM, Guenter Roeck wrote: > > On 4/17/23 13:55, Dinh Nguyen wrote: ... > > ... and this contradict each other. If bit 31 indicates an error, > > this can not be a signed 32-bit value. > > > You're right! I've re-read the spec and should have the the code look for > the specific error values: > > 0x80000000 - inactive > 0x80000001 - old value > 0x80000002 - invalid channel > 0x80000003 - corrupted. No, they are not hex. Probably you need to define an error space with it, but at least just use signed _decimal_ values. Instead of BIT(31) this should go as #define ..._ERR_BASE INT_MIN // or equivalent if the type is not int #define ..._ERR_MAX ... // or whatever name is better Then in your code if (value >= _ERR_MAX) return 0; err = _ERR_MAX - value; switch (err) { ... } P.S. I asked during internal review if the values are bit fielded when errors. AFAIU that time they are, now it seems different. -- With Best Regards, Andy Shevchenko