MPC5674F Standard Math Libraries are not working

[timias]

Any Suggestions?

building a project for mpc5674F in Codewarrior 10.2

Using Software floating point support and default options from project

I did add #define _EWL_FLOATING_POINT 1 in MPC5674F_INT_RAM.prefix otherwise it won't compile.

The following function should return 45 in test... instead it returns 0.737107076324373

#include "MPC5674F.h"

#include <stdio.h>

#include <math.h>

#define PI 3.14159265

double test;

int main(void) {

  volatile int i = 0;

  test = atan(1.0f) * 180 / PI;

  /* Loop forever */

  for (;;) {

    i++;

  }

}

[timias · Accepted solution]

Freescale support assisted me in with this defect. CW 10.2 libraries for MPC 5674F were defective- The #pragma work around fixed the issue, and CW10.3 beta 3 doesn't seem to exhibit the same problem.

[timias]

Update: There is a bug in the Freescale libraries, and a defect has been added. A temporary workaround has been offered

It’s a codegen bug, turn off inlining for the function that makes the call :

#pragma dont_inline on

int main(void) {

  volatile int i = 0;

testf = atanf(1.0f) * 4.0 / PI;

sqrtAnswer = sqrtf(4600.0f);

/* Loop forever */

for (;;) {

i++;

}

}

#pragma dont_inline reset

If the user adds the f suffix to all constants (4.0f and PI) then faster SPE codegen will happen but inlining need to be kept off.

[timias]

Well the libraries are more defective the more I investigate.

2 functions I am testing with

atanf

sqrtf

Software Floating Options = atanf works, but sqrtf crashes the processor

SPE-EPFU ( HW for Single precision)= atanf gives wrong answer, but sqrtf works.

This has all been done using brand new projects created with the bareboard wizard in CW 10.2

[timias]

I used SPE-EFPU Options for floating point support from the Bareboard Project wizard, if I select Software Floating point support it works.