ARM-CGT: Release build removes code from TCM

Nilabh Anand

Part Number: ARM-CGT
Other Parts Discussed in Thread: MCU-PLUS-SDK-AM263PX, MCU-PLUS-SDK-AM261X

Tool/software:

Hi Experts,

I am trying to compile an example where I am placing the function code in TCM memory location:

static __attribute__((__section__(".text.armiqmath")))_iq24 _IQ24mpy1(_iq24 A, _iq24 B)
{
_iq24 result;
__asm__ volatile(
"smull r2, r3, %1, %2\n"
"lsr r2, r2, #24\n"
"lsr r3, r3, #8\n"
"add %0, r2, r3\n"
: "=r" (result)
: "r" (A), "r" (B)
: "r2", "r3", "cc"
);
return result;
}

//GLobal variables:

volatile _iq24 a ;
volatile _iq24 b ;

//main function

void main(void *args)
{

Drivers_open();
Board_driversOpen();
volatile _iq24 result;

result = _IQ24mpy1(a,b);
{

---do processing based on variable result

}

The behavior I see is that in debug build the code is present in TCM location but when I am trying to build in release mode the TCM location is empty(observations are based on generated map file)

Below is release build map file

This is debug build.

Why is this behaviour seen?

Regards

Nilabh A.

10 months ago

0 Nilabh Anand 10 months ago

TI__Mastermind 44364 points

I am using the TI-ARM clang compiler 4.0 LTS version with MCU PLUS SDK AM263Px

0 George Mock 10 months ago

TI__Guru**** 249175 points

I need to see the details of how you implement ...

Nilabh Anand said:
placing the function code in TCM memory location

Please attach the linker command file to your next post. So it is accepted, please add the file extension .txt.

Thanks and regards,

-George

0 Nilabh Anand 9 months ago in reply to George Mock

TI__Mastermind 44364 points

Hi George,

Sharing the whole project with linker /cfs-file/__key/communityserver-discussions-components-files/908/code_5F00_placement_5F00_TCMA.zip

+1 George Mock 9 months ago in reply to Nilabh Anand

TI__Guru**** 249175 points

Thank you for ...

Nilabh Anand said:
Sharing the whole project with linker

It does not use MCU-PLUS-SDK-AM263PX. It uses MCU-PLUS-SDK-AM261X. I am unable to find that SDK, thus I am unable to build the project as sent. However, I did work through it enough to find the likely cause of the problem.

The function _IQ24mpy1 is static, and called one time in the source file. The compiler inlines this one call, and never generates code for the function. Thus the code for the function ends up in the same section as the function which calls it, and not in the desired section .text.armiqmath. One solution is to add the noline attribute, with code similar to ...

__attribute__((__section__(".text.armiqmath"), noinline))

Thanks and regards,

-George

0 zhou nanyi 9 months ago in reply to George Mock

Prodigy 135 points

Hi George,

I am attempting to port a large project from DSP (28375) to ARM (AM261X) to improve computational speed. Therefore, I need to port the math library. Due to the large workload, I will not convert the entire project's calculations to floating-point for now. Since the IQmath on DSP is not suitable for ARM, I need to use assembly to implement fixed-point calculations similar to IQmath. Because the AM261X has a TCM module that can enhance computational speed, I would like to know whether placing mathematical computations in TCM (iqmpy, iqdiv, iqsqrt, iqsin, iqcos, etc.) and then calling them from OCM RAM is faster than doing all calculations in RAM.

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ARM-CGT: Release build removes code from TCM