CCS/TMS320F280025: Division operation cannot run in fastRTS

Linda Zhang84708

Part Number: TMS320F280025
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

Hello Champs,

In "epwm_ex1_trip_zone" project in "C:\ti\c2000\C2000Ware_3_02_00_00\driverlib\f28002x\examples\epwm", below configuration has been set for using fastRTS:

Then add below definition in "epwm_ex1_trip_zone.c":

float X1 = 5.0;

float X2 = 15.0;

float X3,X4;

and add below sentences at beginning of main():

X3 = X2/X1;

X4 = sinf(X1);

After compiling it can be found out in ".map" file that "sinf" operation has been located into "rts2800_fpu32_fast_supplement_eabi.lib":

0000ad24 00000034 rts2800_fpu32_fast_supplement_eabi.lib : sin_f32.obj (.text)

But the "/" operation is always in "rts2800_fpu32_eabi.lib" and cannot be located into "FS$$DIV" in "rts2800_fpu32_fast_supplement_eabi.lib" as described in fastRTS manual:

0000aa53 00000088 rts2800_fpu32_eabi.lib : fs_div28.asm.obj (.text)

The "rts2800_fpu32_fast_supplement_eabi.lib" used is from "C:\ti\c2000\C2000Ware_3_02_00_00\libraries\math\FPUfastRTS\c28\lib". CCS version is 10.0.0.00010, compiler version is v19.6.0.STS.

Would you please kindly help? Thanks!

Best Regards,

Linda

over 5 years ago

0 Linda Zhang84708 over 5 years ago

TI__Expert 6620 points

add another configuration picture:

0 Sira Rao80 over 5 years ago in reply to Linda Zhang84708

TI__Mastermind 26320 points

Linda,

Let me explore this for you (why sinf invokes the FPUFastRTS library but / does not), but on the F28002x you should be doing both Trig and / operations on the TMU (--tmu_support = tmu1). Why aren't you doing that? That will be 10 times faster than the FPUFastRTS library.

Thanks,

Sira

0 Linda Zhang84708 over 5 years ago in reply to Sira Rao80

TI__Expert 6620 points

Hello Sira,

Would you please kindly help on this FPUfastRTS issue? Thanks!

Best Regards,

Linda

0 Sira Rao80 over 5 years ago in reply to Linda Zhang84708

TI__Mastermind 26320 points

Linda,

OK, I'll get back to you in a day or so.

Thanks,

Sira

0 Sira Rao80 over 5 years ago in reply to Sira Rao80

TI__Mastermind 26320 points

Linda, I looked at the generated .asm and I see the call to c28xabi_divf, which is in the RTS library. In fact, even the FastRTS division example seems to exhibit the same issue. I will continue looking into this and will get back to you.

Thanks,

Sira

0 Sira Rao80 over 5 years ago in reply to Sira Rao80

TI__Mastermind 26320 points

Linda,

My colleague Himanshu looked into this issue and found the potential bug.

in the div_f32.asm file of the FPUFastRTS library, the global directive for FS$$DIV is called before the .asg directive to __c28xabi_divf, which is why it does not get resolved to the fastRTS lib. Can you make the change, rebuild the library, use it in the project, and see if it resolves the issue?

Please let me know.

Thanks,

Sira

0 Sira Rao80 over 5 years ago in reply to Sira Rao80

TI__Mastermind 26320 points

I confirmed with my tests that this fixes the issue. I will file a JIRA to have this fixed in the next C2000Ware release. You can use the fix at your end.

0 Linda Zhang84708 over 5 years ago in reply to Sira Rao80

TI__Expert 6620 points

Hello Sira,

Thank you for your kind help.

There are still questions listed below:

1) How to modify "div_f32.asm" file? Can you explain it in detail?

2) There is a project named "rts2800_fpu32_fast_supplement" in the folder “C:\ti\C2000Ware_3_02_00_00\libraries\math\FPUfastRTS\c28\ccs\fpu32”, after being compiled, it will generate "rts2800_fpu32_fast_supplement_coff.lib" in the folder "C:\ti\c2000\C2000Ware_3_02_00_00\libraries\math\FPUfastRTS\c28\lib", but cannot find the source file to generate "rts2800_fpu32_fast_supplement_eabi.lib".

Would you please kindly help? Thanks!

Best Regards,

Linda

0 Sira Rao80 over 5 years ago in reply to Linda Zhang84708

TI__Mastermind 26320 points

Linda,

I have pasted below the corrected portion of div_f32.asm. This is at the beginning of the file itself. You can paste this into the file.

.page
.text
.if __TI_EABI__
.asg __c28xabi_divf, FS$$DIV
.endif
.global FS$$DIV

Also, you are looking at the COFF version of the project. You will want the EABI build configuration (ISA_C28FPU32_EABI). That will build the new _eabi.lib.

I am attaching the new file for your referencerts2800_fpu32_fast_supplement_eabi.lib.

Thanks,

Sira

0 Linda Zhang84708 over 5 years ago in reply to Sira Rao80

TI__Expert 6620 points

Hello Sira,

Now the issue has been solved. Thank you so much for your kind help.

Best Regards,

Linda

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CCS/TMS320F280025: Division operation cannot run in fastRTS