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Problem with IQmath in Cortex-M4

Ales Jelinek
Prodigy 20 points

Hello,

I have a problem with conversion functions of IQmath in CCS 5.3. I am trying Stellaris LaunchPad with LM4F120H5QR microprocessor. I am using IQmath version 9453 (file IQmathLib-cm4f.lib). When I want to use conversion function _IQ26toF, which conversions a type format iq26 to a type float, result of _IQ26toF isn’t correct.

I looked at disassembly window to assembler code and I found this thing:

Compiler expects result value of _IQ26toF function in register S0, but there isn’t used register S0 in _IQ26toF function (see next figure).

Result value in register R0 is correct, but result type of _IQ26toF function is type float, because compiler expects results value in register S0. It is my opinion.

Many thanks for your efforts!

Jiri Paar