I'm trying to build the VxWorks kernel using gcc 7.3. It builds and boots, but I'm having a problem with use of fpr f0 from interrupt context. An ISR ends up calling a function taking an unsigned long long, which is passed on to another function; the assembly code for shuffling that argument around is 153698: c8 01 00 68 lfd f0,104(r1) 15369c: d8 01 00 18 stfd f0,24(r1) and the first instruction triggers an exception. This is apparently gcc being clever and using just two instructions for loading/storing 64 bits. It seems I can avoid the generation of these instructions with -msoft-float, but that's somewhat of a big hammer, as I do want to use the FPU for the stuff running in task context. I suppose I could try to apply -msoft-float just to the TUs that might be called from interrupts, but what I'm looking for is a switch to avoid using FPRs for integers (i.e., it's fine to use the FPU when the source code actually works on floats or doubles). Is there such a switch I'm overlooking? Thanks, Rasmus
