CCS/TMS320F28069: Problem on inline assembly

Yash Shah

Part Number: TMS320F28069

Tool/software: Code Composer Studio

Hey,

Now suppose we have three unsigned int global variable and access using its address available in MAP file during a run time like this

But our problem on 4th line this asm(" MOVL ACC,*XAR6); one its content load ok but original content available in AH (accumulator high) part so how to extract the AH part in Full ACC we do not require an AL(accumulator LOW )part. I have already tried the shifting by 16 but not working can you suggest me proper shifting in inline assembly or another method?

asm(" MOVW DP,#_a"); // load page address
asm(" MOVL ACC,@_a); // load the value in ACC available in a
asm(" MOVL XAR6,ACC);
asm(" MOVL ACC,*XAR6); // Variable value using indirect addressing mode

asm(" MOVW DP,#_b);
asm(" MOVL @_b,ACC); // Transfer the value ACC in another variable

Regards

Yash shah

over 5 years ago

0 Richard Poley over 5 years ago

TI__Mastermind 27200 points

Yash shah,

Just from the assembly perspective, I believe you could do this by adding the following after the 4th line:

asm(" MOV AL, @AH");
asm(" MOV AH, #0");

There are some general guidelines for inserting inline assembly into C files on p.164 of the C compiler User's Guide, here:

http://www.ti.com/lit/ug/spru514s/spru514s.pdf

In general, for lengthy sections of assembly code, particularly those which modify C variables, it's safer to write and call an assembly function.

Regards,

Richard

0 Yash Shah over 5 years ago in reply to Richard Poley

Intellectual 585 points

Hey,

We are resolve the problem using the new develop few line of inline assembly code. Another thing is any way to check the that code is disturb our C or C++ environment?

Regards

Yash Shah

0 Richard Poley over 5 years ago in reply to Yash Shah

TI__Mastermind 27200 points

Aside from the general recommendations in the user's guide there isn't anything I know of. Keep in mind that the C optimizer will not rearrange code lines around your inline assembly.

One thing I forgot to mention is to be careful about relying on the offsets from the .map file for assigning variable addresses. As your program grows the linker may move variables around to optimize memory use so the symbols may not always be where you expect.

Regards,

Richard

0 Yash Shah over 5 years ago in reply to Richard Poley

Intellectual 585 points

Hey,

Yes, but we can access the variable using its name not using its address. In naming accessing create that type of problem?

Regards

Yash shah

0 Richard Poley over 5 years ago in reply to Yash Shah

TI__Mastermind 27200 points

Yes, that's correct. If you are using symbols to load the addresses then it should be fine.

Regards,

Richard

0 Yash Shah over 5 years ago in reply to Richard Poley

Intellectual 585 points

Hey,

Thanks, for support Now finally we can access all types of variables during run time.

Regards

Yash shah

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CCS/TMS320F28069: Problem on inline assembly