TMS320F280049: Calling Device_cal safely from optimised code

Gareth Hanahoe

I've had some problems with Device_cal() changing the state of CPU registers (specifically XAR3) which the compiler is using to store automatic variables. From looking at the disassembly for Device_cal(), it doesn't appear to push CPU registers onto the stack. I'm calling it from in an initialisation function, so before interrupts are enabled.

My optimisation settings are O2 with optimise for speed = 2. The flags excluding include paths etc are: v28 -ml -mt --cla_support=cla2 --float_support=fpu32 --tmu_support=tmu0 --vcu_support=vcu0 -O2.

Do you have any recommendations on how to ensure that Device_cal() can be called safely from optimised code?

over 7 years ago

0 Whitney Dewey over 7 years ago

TI__Guru 54345 points

Hello,

I'm guessing you're calling Device_cal() in your code as a temporary measure until we get it added to the GEL file?

Yeah, it looks like Device_cal() is not following the "save on entry" convention. I think you'll need to do the save and restore yourself. See if doing it with __asm() works.

Whitney

0 Gareth Hanahoe over 7 years ago in reply to Whitney Dewey

Prodigy 30 points

Yes that's correct.
I'll try writing some __asm() statements. It looks like I'll need to store XAR0, XAR2 and XAR3 to be safe.

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TMS320F280049: Calling Device_cal safely from optimised code