Which floating point operations generate quiet/signalling NaN?

I'm designing an FPU in a logic simulator and I need to know which operations generate the two kinds of NaNs (quiet: qNaN and signalling: sNaN)

edit: I've found out that arithmetic operations like 0*infinity always generate qNaNs (source: http://www.savrola.com/resources/NaN.html). What I still don't know however is if there are any other ways to get sNaNs beside setting a variable to sNaN's bit pattern.

Solution

I assume you have some sort of textbook or spec on whatever floating point spec you intend to simulate. Look in there for definitions.

For something more general, you can read: http://en.wikipedia.org/wiki/NaN

Here is what wikipedia says on sNaNs:

Signaling NaN
Signaling NaNs, or sNaNs, are special forms of a NaN that when consumed by most operations should raise an invalid exception and then, if appropriate, be "quieted" into a qNaN that may then propagate. They were introduced in IEEE 754. There have been several ideas for how these might be used

Filling uninitialized memory with signaling NaNs would produce an invalid exception if the data is used before it is initialized

Using an sNaN as a placeholder for a more complicated object, such as:

A representation of a number that has underflowed

A representation of a number that has overflowed

Number in a higher precision format

A complex number