Converting my legacy code for FPU

Ted Lee57324

Prodigy 180 points

Other Parts Discussed in Thread: CONTROLSUITE

Hi there!

I'm currently planning a project based on TMS320F28335.

At this moment, from my boss, I've gotten legacy project(SW) that is generated for TMS320C2812.

And he'd like to re-use those source codes for my new project.

Also he'd like to minimize the code change because those codes could be re-used for Fixed Point machine.

However! His legacy codes were implemented by Qmath(not by IQmath) like this!

/* All variables are defined as "int" type */

        /* Let's say Vas_ref, Vbs_ref, Vcs_ref, Vsn is Q5 */
      Van_ref = Vas_ref + Vsn;
        Vbn_ref = Vbs_ref + Vsn;
      Vcn_ref = Vcs_ref + Vsn;

        /* Let's say INV_Vdc is Q23 */
      Ta = 0x2000 - ((long)Van_ref*(long)INV_Vdc >> 14); // Q(5 + 23 - 14)
        Tb = 0x2000 - ((long)Vbn_ref*(long)INV_Vdc >> 14); // Q(5 + 23 - 14)
      Tc = 0x2000 - ((long)Vcn_ref*(long)INV_Vdc >> 14); // Q(5 + 23 - 14)

Here is my query.

What's the best practice to minimize the change in my legacy code?

Is there any reference document for solving this prolem?

I'd like to fully utilize the FPU performance of 28335 !!!

That is, I'd like to define my variables as "float" type instead of "int" type!

I'm looking forward to your answer.

Thanks.

over 14 years ago

0 Charlie3036 over 14 years ago

TI__Intellectual 1615 points

Ted,

Take a look at this document http://focus.ti.com/lit/an/spraaq7b/spraaq7b.pdf It is the migration guide from the F2812 to the F28335. This should help with some of this. For the Q value variables you'll need to convert all of this to float if you want to take advantage of the FPU. Most of the FPU's advantages come from code designed for floating point, so to really see the benefits you might need to re-architect your algorithm to take advantage of the FPU.

Charlie

0 ChrisClearman over 14 years ago

TI__Guru** 119510 points

I think you should take the time to port your existing code first to IQMath, verify it works as expected, then make the few changes needed to take advantage of the FPU (and new peripherals on F2833x).

0 Charlie3036 over 14 years ago in reply to ChrisClearman

TI__Intellectual 1615 points

Chris has a good point. I would recommend downloading and installing controlSUITE and looking at IQMath. There are some very good examples and documents there. Open the controlSUITE program and look under libraries. I think you'll find lots of good information there. www.ti.com/controlsuite

Charlie

0 Ted Lee57324 over 14 years ago in reply to ChrisClearman

Prodigy 180 points

Chris, thanks for your kind advice!

Charlie, I'll check out controlSUITE examples right now.

I really appreciate your help.

Ted.

C2000™︎ microcontrollers

C2000 microcontrollers forum

Converting my legacy code for FPU