MSP430F5529: Avoid use of mspabi optimisation code

Michele Grisafi

Part Number: MSP430F5529

Hello everyone, I'm writing a custom code instrumentation tool which requires to have the source code of all of the application binary. Basically my problem is that the application, whose source code is available, when compiled automatically generates some additional code which is used for optimisation. This code, however, does not correspond to any source file which is one of my requirements.

As a consequence I need to do one of the following three things:

Access the source or assembly code of this optimisation code
Prevent mspgcc from including and using it, thus forsaking the optimisation
Include my own version of the optimisation (already instrumented)

The optimisation code I'm talking about is the one referred to as "__mspabi...", such as "__mspabi_srll_8", or "__mspabi_slll_1" and so on. This code allows the application to use the same piece of code when doing multiple shift operations, jumping to these labels whenever necessary.

IS anybody able to help me? Thank you

I'm using mspgcc 9.2.

over 5 years ago

0 Aaron Barrera over 5 years ago

TI__Mastermind 26046 points

Hi Michele,

We are looking into this and will get you a reply by the end of the day.

Have you reviewed Section 3 of the MSP430 Optimizing C Compiler User's Guide?

0 David Schultz over 5 years ago

Guru 25955 points

The compiler will always use code from behind the curtains to do certain things even without optimization. Integer multiplication and division for example. The code is available in the compiler source. Looking at some old mspgcc code (what I have) it is in: gcc-4.6.3/gcc/config/msp430

0 Aaron Barrera over 5 years ago in reply to David Schultz

TI__Mastermind 26046 points

Hi Michele,

Here are some more resources that can help you:

MSP430 Embedded Application Binary Interface: https://www.ti.com/lit/pdf/slaa534

MSP430 GCC Toolchain User's Guide: https://www.ti.com/lit/pdf/slau646

The User's Guide will have the optimizations & the settings to turn off the mspabi_srll type of operations (pg. 15). You can use Optimization Level O0 to disable all optimizations and generate unoptimized linear assembly language code.

0 Michele Grisafi over 5 years ago in reply to Aaron Barrera

Prodigy 120 points

Thank you for the reply, however the use of such code is independent of the optimisation flag used. Using -O0 will still output code with mspabi invocations. I will probably need to compile my own libgcc.a library in order to instrument that code. It's not going to be easy but I think it is the only solution.

Thanks again

0 Jozef_Lawrynowicz over 5 years ago in reply to Michele Grisafi

Expert 2410 points

The -mmax-inline-shift option should solve your problem.

Try -mmax-inline-shift=64 so that GCC will always emit code for shifts instead of branching to a helper function.

Regards,

0 Michele Grisafi over 5 years ago in reply to Jozef_Lawrynowicz

Prodigy 120 points

Thanks for the suggestion. Although that directive definitively seems like a legit solution it doesn't work. The code produced with that option enabled still contains the calls to the helper functions.

0 Jozef_Lawrynowicz over 5 years ago in reply to Michele Grisafi

Expert 2410 points

It works for me. Please post a reproducible test case for when it's not working.

Thanks,

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

MSP430F5529: Avoid use of mspabi optimisation code