On page 241 of the VR4300 User Manual here is Q to the power -1:
8.2.4 Divide-by-Zero Exception (Z)
The Division-by-Zero exception occurs if the divisor is zero and the dividend is a
finite nonzero number. This exception occurs due to other operations that produce
a signed infinity, such as ln(0), sec(pi/2) or Q^-1.
What does Q to the power -1 mean?
(Edit: updated to note that it’s the User’s Manual which says this. For reference, here’s the datasheet.)
Q could be a mistaken zero, especially one with a slash through it.
Yes, good thought, it’s a zero - see here for example
I found a different (later) version of that datasheet which definitely says Q^-1: https://hack64.net/docs/VR43XX.pdf. So, definitely should be O^-1, and also definitely isn’t, in the later version of the datasheet.
Q also means the set of rational numbers, but that doesn’t make much sense.
Could be a warning not to create a floating point number with 0 in the significand and -1 in the exponent. You’d think you’d want a way to catch that kind of mistake.
I suspect it could also have gotten confused with Quiet Not a Number (Q-NaN) which is also mentioned in that manual.
