floating point operations with and without Custom instruction floating point hardware

You'll need to pass in compiler flags so that it knows that the hardware is present. To determine if it's working I normally look at the objdump file to see if software libraries are being replaced with the 'custom' mnemonic. Here is an old FPU custom instruction you can take a look at to see how to make the compiler aware of the hardware: http://www.nioswiki.com/custom_floating_point_unit