CCS/MSP430FR6922: CCS 7/MSP430FR6922 Optimization problems

user5163417

Prodigy 40 points

Part Number: MSP430FR6922

Tool/software: Code Composer Studio

Good morning,

I use msp430fr6922 with CCS 7.

I have problem with optimization - It is cut "if", I attached screens with code and disassembly.

If I set optimization to off(OPToff), code work fine.

If I set whole program opt to 0(OPTeveryto0), "while and if" are cut away.

If I set whole program opt to 1 (OPTeveryt1), "if" are cut away.

How shall I set optimization to work fine?

Thank you to response

over 5 years ago

0 Tomasz Kocon over 5 years ago

Guru 26200 points

Ahoj!

compiler sees that both AdrRegistersTx and Nack v are always equal to 0 and
it finds the conditions for "while" and "if" statements are always false.

Are AdrRegistersTx and Nack volatile or nonvolatile?

0 user5163417 over 5 years ago in reply to Tomasz Kocon

Prodigy 40 points

Ahoj Tomasz,

Variables are define like global char variables, I tryied write before "volatile" - but it doesn´t have any effect.

Variables values = 0 and in interrupt variables are modify. Is it wrong?

0 Tomasz Kocon over 5 years ago in reply to user5163417

Guru 26200 points

Do you have all your code in one source file.
What about extern volatile ...?

0 user5163417 over 5 years ago in reply to Tomasz Kocon

Prodigy 40 points

Now I have small changes in program, but for my question it will be suffice.

I attached two pic. First is pic with OPT off and second with OPT 0. Dissasembly code are the same except for the marked commands. Why? Can I get tip, where is basic overview of all disassembly comands? Why in disassembly some lines from C editor are cut?

These two code works same and good, but disassembly is different.

Petr Drábek

0 Tomasz Kocon over 5 years ago in reply to user5163417

Guru 26200 points

Hello,

user5163417 said:
Dissasembly code are the same except for the marked commands. Why?

Different optimization level.

user5163417 said:
Can I get tip, where is basic overview of all disassembly comands?

http://www.ti.com/lit/ug/slau367o/slau367o.pdf

user5163417 said:
Why in disassembly some lines from C editor are cut?

In this simple case we can discuss is this an error or not.
However, in some cases, optimization changes the code so much that statements and loops disappear.
Please refer to an example related to volatile key.

0 user5163417 over 5 years ago in reply to Tomasz Kocon

Prodigy 40 points

Good morning,

thank you to response.

For now that will have to be enough for me.

Best Regards

0 Tomasz Kocon over 5 years ago in reply to user5163417

Guru 26200 points

Good afternoon,
from Warsaw, GMT+1.
Glad you have a homework.

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CCS/MSP430FR6922: CCS 7/MSP430FR6922 Optimization problems