How to use a math instruction from FPU instruction set?

Prakash Kumar Thulasi Kumar

Expert 2015 points

Hi Guys,

CCS v 6.2(compiler version = TI v15.12.3.LTS)

TMX320F28075 Control Card

control Suite v 3.4.1

I am going through the SPRUHS1A document. I need to use the absolute function (ABSF32). I called it as follows:

V_D_temp = __ABSF32(V_D_temp);

And I get an error. Please let me know how to call this function and other functions(Multiplying two float and adding two float) of the FPU Instruction Set.

Also please tell me if there is any Saturation function similar to _IQsat() in FPU or TMU.

over 9 years ago

0 Vishal_Coelho over 9 years ago

TI__Mastermind 20850 points

Hi Prakash,

There is no intrinsic for the ABSF32 instruction. You use the fabs() instead, if you have the fpu32 option turned on the compiler will use the ABSF32 instruction.

0 Prakash Kumar Thulasi Kumar over 9 years ago in reply to Vishal_Coelho

Expert 2015 points

Hi Vishal,
Thanks. Where can I find such functions for all those instructions mentioned in 1.5.2 in SPRUHS1A document?

0 Vishal_Coelho over 9 years ago in reply to Prakash Kumar Thulasi Kumar

TI__Mastermind 20850 points

Prakash,

Those are the assembly instructions - you will not find C intrinsics for all of them. But for the complete list of available intrinsics i'd refer you to the compiler guide (SPRU514), section 7.5.6, table 7-6. For the floating point intrinsics see Table 7-7

0 Prakash Kumar Thulasi Kumar over 9 years ago in reply to Vishal_Coelho

Expert 2015 points

Thank You Vishal :)
I have been searching for this document.

0 Prakash Kumar Thulasi Kumar over 9 years ago in reply to Vishal_Coelho

Expert 2015 points

Vishal,
One more question. Is there any intrinsic function in FPU or TMU to roll within 0 and 2PI?

0 Vishal_Coelho over 9 years ago in reply to Prakash Kumar Thulasi Kumar

TI__Mastermind 20850 points

Prakash Kumar Thulasi Kumar said:
Is there any intrinsic function in FPU or TMU to roll within 0 and 2PI?

Not sure i understand Prakash, could you give me the pseudo code for the operation you are looking for?

0 Prakash Kumar Thulasi Kumar over 9 years ago in reply to Vishal_Coelho

Expert 2015 points

								
	if (angle < 0)												
		angle += 6.283185307179586476925286766559;				
	else if (angle >= 6.283185307179586476925286766559)			
		angle -= 6.283185307179586476925286766559;

To roll the angle in radians within 0 and 2pi.

0 Vishal_Coelho over 9 years ago in reply to Prakash Kumar Thulasi Kumar

TI__Mastermind 20850 points

Prakash,

I dont think any of the FPU or TMU intrinsics can do this. I think you will have to write this in C, or C-callable assembly function.

0 Prakash Kumar Thulasi Kumar over 9 years ago in reply to Vishal_Coelho

Expert 2015 points

Thanks Vishal :)

C2000™︎ microcontrollers

C2000 microcontrollers forum

How to use a math instruction from FPU instruction set?