Variable initialization.

Michael Morgan

Prodigy 180 points

int y = 0;

int y1;

void f1(void)

{

y = 2;

y1 = 2;

}

When I reset the processor y gets reset to 0 and y1 remains at 2. Most C compiler I have used will also reset y1 to 0. I know this is not define in the C standard. Is there an easy method of clear ALL the RAM before use?

over 12 years ago

0 Bill Finger over 12 years ago

Genius 3735 points

In your linker command file, specify a fill value for the .bss section.

So you may have:

SECTIONS

{

.bss > DARAM

}

Change it to:

SECTIONS

{

.bss > DARAM, fill = 0

}

Note this will greatly increase the size of your program image.

0 George Mock over 12 years ago in reply to Bill Finger

TI__Guru**** 251490 points

The previous post is correct. More explanation can be found in this wiki article.

Thanks and regards,

-George

0 Michael Morgan over 12 years ago in reply to Bill Finger

Prodigy 180 points

Bill,

This does work but only the first time the code in loaded into the CCS Debugger. How can I initial all the data to 0 without have to re launch the debugger each time?

Michael.

0 Bill Finger over 12 years ago in reply to Michael Morgan

Genius 3735 points

You will have to reimplement _auto_init, so that it zeros the .bss section every time it runs. It sounds scary, but it should be pretty easy. Find the function in the real time library source, and before it copies data from .cinit to the initialized sections of .bss, zero every word in .bss. It will give you some practice in C55x assembly. :^)

0 Michael Morgan over 12 years ago in reply to Bill Finger

Prodigy 180 points

I had already written the asm but could not workout how to call it before the standard init code. Have got it know. Thanks.

Michael.

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Variable initialization.