by default printf and all flavor (aka vsprintf etc..) come without support for float on the std lib ther’s may be some some option or over lib that enabel or add float support

Hello all,

Looking at this problem, we just discover it was probably due to a small glitch in the linker script provided by ST. There was, near the beginning of the fine a line that reads

_estack = 0x2000FFFF;    /* end of RAM */

This should be, in fact, a byte higher, just after the end of the RAM area, that is:

_estack = 0x20010000;    /* end of RAM */

The problem is that the original setup creates a stack pointer that is not 8-byte aligned, thus causing problems when storing double values in the stack or passing them as parameters.

Editing the linker script shoul correct the problem, so keep us informed. Anyway the correction will be in the next update, due beginning of August.

Bernard

Hello Bernard,

Thanks for the help. I have suspected that there’s an error in the linker directive earlier, but I do not have enough knowledge to modify it.

I got the printfs working for the floats if I used the supplied GCC’s linker scripts and initialization code ones, but I have to set up the tool chain manually. Luckily there is the OpenSTM32, so I can develop the firmware easier.

By the way, could you add the “Enable float for printf” and the “Enable Semihosting” and/or “Enable SWO” checkboxes in the “Project Options”? This allows the programmer to decide whether he/she wants to enable these in the project.

How did you make the printf work ? Did you use the Liviu Ionescu trace library ?

I cannot get sprintf to work with floats either.

I checked the linker script and the _estack is fine

_estack = 0x20020000; /* end of RAM */

I am using an M4 and have the Hard FPU selected.

How do I enable printf with float?

Hi all,

I am also having issues with printf and sprintf. The codebase which I am using was generated using cubemx for the MCU STM32F103VET. When I use printf in my code Execution is jumping to hard fault handler. Also seeing some weird memory overflow kind of behavior with sprintf.

But these two functions are working well in the firmware (generated by using cubemx) for STM32F103RB.

Are there any issues in the linker script of the STM32F103VET project?