Nios II freezes when printing double values/ does not print float values

Altera_Forum · ‎11-18-2015

Hi there,

I´m using the MAX10 Eval Board with a 10M08SAE144C8GES FPGA and an Nios II/f processor.

But when i try to print a float value the JTAG output just skips the value.

I´m using the Hallo_world_Small template:

# include <stdio.h># include "system.h"# include "sys/types.h"# include "altera_nios_custom_instr_floating_point_2.h"

int main ( void ) {

__uint64_t PI = 3.1415926535;

if(PI > 3.141592653) printf ("True\n");

printf("PI: %f" ,PI);

printf("Hello_World\n");

printf("Sizeof(PI) %d",sizeof(PI));

printf("Goodbye\n");

printf("\n");

}

OUTPUT:

PI: Hello_World

Sizeof(PI)

Seems that the processor freezes.

Any ideas on that?

Thank you very much!

Altera_Forum · ‎11-20-2015

Is your Nios CPU compiled with the floating point custom instructions? If not you need to use software emulation. I think there is a compiler flag for it.

Second, __uint64_t sounds more like a integer type, and using it with a %f in printf may lead to undefined behaviour.

Altera_Forum · ‎12-16-2015

Maybe can refer to this procedure.

https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/tt/tt_floating_point_custom_instructions.pdf