topic Problem returning double from a function. in CodeWarrior for MCU

Problem returning double from a function.

leccy — Wed, 29 Jun 2016 08:46:33 GMT

I am migrating an existing CW10.4 project to include USB with bootloader on a product.

Starting with the existing project, i have copied in P&E components, .lcf files etc from another product which already has USB working. This is now working as expected.

However, the new project is not returning a double correctly, whereas the existing project does.

As far as i can tell, all the project settings are the same, both use Codewarrior ARM C compiler etc.

I have attached screenshots showing a difference in assembler between the two projects where the double is returned from a function. These functions are identical in source code.

There must be a setting somewhere i have missed...

I've seen on non-kinetis CW that you can specify if double is 32bit or 64bit, but can't find this for kinetis. Could it be related to this?

Thanks

Alex

Re: Problem returning double from a function.

leccy — Wed, 29 Jun 2016 12:45:17 GMT

In "Double return fails.png",

the line bl $T (0x1d26c)

is the address of "(FP_fastI_Thumb_LE_v7M.a _d_itod.o )"

So it would appear be calling a library integer to double function.

Re: Problem returning double from a function.

leccy — Thu, 30 Jun 2016 10:28:54 GMT

Fixed this issue.

I had left out an include file which contained the function which was returning double in the file where the function was being called.

This did not produce an error on compilation.

Introducing the include file changes the assembler produced to correctly return double.