Parameter Alignment

Beginner

Intellectual 2471 points

Hi all,

I try to declare four parameter like the following in CCS.

char fCmdStore[3]; (3 bytes)

char fReserve13; (1 bytes)

char fCmdDataCnt[3]; (3 bytes)

char fReserved17; (1 bytes)

After complire finished, I check the map file and show as below:

20003f59 fCmdDataCnt;

20003f54 fCmdStore;

20003f58 fReserve13;

20003f5d fReserved17;

The parameter in RAM address is not my expecation.

I think it should be word alignment, is it ? By word alignment,

I think the variable address as below:

20003f50 fCmdDataCnt;

20003f53 fCmdStore;

20003f54 fReserve13;

20003f57 fReserved17;

over 13 years ago

Archaeologist over 13 years ago

TI__Guru* 84285 points

Because those identifiers have been assigned addresses, I know that these are global variables.

The address of fCmdDataCnt, fReserve13, and fReserved17 are identical; is this a cut-and-paste error in your forum post?

What ISA are you using?

Beginner over 13 years ago in reply to Archaeologist

TI__Intellectual 2471 points

Thanks. Some error in the address number and I have been modified.

With a 32-bit MCU, CCS v.5.2 is used to complier.

Archaeologist over 13 years ago in reply to Beginner

TI__Guru* 84285 points

You said you are using MCU. Can you be more specific about the ISA? Are you using ARM, MSP430, or C2000?

Beginner over 13 years ago in reply to Archaeologist

TI__Intellectual 2471 points

Dear Sir,

I am using LM4F232.

Archaeologist over 13 years ago in reply to Beginner

TI__Guru* 84285 points

LM4F232 is an ARM Cortex-M4F device.

For ARM, I see nothing wrong with the addresses of the variables you describe. What exactly do you believe is in error? Do you believe that these variables should be 32-bit aligned, or do you believe they should be in a different order in memory?

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Parameter Alignment