MDagg

Both in fact. My point is that there is viable justification for why the 754 designers chose to put 0/0 in the class of invalid operations and not in the division by zero class.

It is worth knowing that from real analysis that 0/0 is a symbol and not a division at all. One could attempt a clever argument that lim 0/x as x-->0 means the same thing as lim 1/x as x-->0 but it does not. All indeterminate forms over the reals are symbols, not operations.

Sure.. I know but I have seen some try to use them to identify results and I didn't want anyone to take what I stated to try to identify indeterminate forms.

Indeed... they did that for making the distinction but I wouldn't suggest using NaN to identify indetermine forms as sqrt(-1) over the reals will get you NaN but its not an indetermine form.

That's only true is you are working in the complex field. Most computer algebra programs work in the complex field by default. In the real field 1/0 is undefined.

Note that 0/0 is an indeterminate form whereas 1/0 is undefined. This is the reason why the errors are different. The Intel FPU does recognize indeterminate forms.

In the embedded controls world, USB is used for maintenance interfaces, if used at all. USB NIC, CAN bus are unreliable as are USB RS232 and become even more unreliable if they are hubs and even though there are numerous expensive non-consumer models, they are rarely chosen. Consumer market hardware is never chosen for a controls design if there is significant liability and insurance companies involved, even if it is just display panel. On the Delphi front, control interfaces written in older versions of Delphi (5-6) were fairly common running under CE, XP embedded and you had a good chance of getting them verifed and insured but not now. Even for newer versions, the verification cost is very high and getting insured is not likely. In fact, I am unware of any insurer that will cover a Delphi-written control program even in in a system with a low-to-moderate hazard score.

It's a toy and in the professional world it's junk. No embedded designer would choose a device like this for a controls design because of liabilty. After all, we are talking about a device that has yet to be made available and from what I see, it has no characteristic operational parameters. Besides, I am not seeing a RJ45 for Ethernet connection, or RS232 serial which would definitely exclude it from PLC modbus use as a master sub module and that is key in embedded designs for controls and general SCADA. Again, it's a toy.