FIX and flags

[alexrp]

I don't really understand the flag settings of the FIX instruction. Is the manual wrong or does it really set the flags based on a floating point interpretation of the *fixed point* result in RD? If it does, that seems quite pointless.

[alexrp]

Similarly, FLOAT appears to compare an input fixed point value to NaN, which would also appear to make little sense.

[aolofsson]

Thanks for catching this!

The FIX instruction checks if the RN input is NAN and sets the BI flag accordingly. (was there something else?)

The FLOAT instruction documentation was a "copy/paste" mistake that needs to get fixed (no checking for NAN there of course)

[alexrp]

What about other flags like BN, BZ, BV, BVS, BUS? Does FIX touch those?

[notzed]

It's a real bummer these don't take the number of bits to fix to/from.

[alexrp]

@aolofsson - ping :)