topic Re: DATA_SEG doesnt work as written in Classic/Legacy CodeWarrior

DATA_SEG doesnt work as written

sureshkumar — Fri, 01 Jun 2007 15:13:41 GMT

Hi Experts,

I have problem in placing a variable in zeropage to use in direct addressing mode. But, when compile and debug in full chip mode, I found all my variable are still in RAM( need to use exended mode to access this) which i dont prefer for timing reason. My codes are;

#pragma DATA_SEG directPAGE

char var1;

int var2;

#pragma DATA_SEG DEFAULT

char others[20];

In PRM file, I have this:

SEGMENTS

ROM = READ_ONLY 0x8000 TO 0xFDFF;

RAM = READ_WRITE 0x100 TO 0x34F;

Z_RAM = READ_WRITE 0x0050 TO 0x00FF;

END

PLACEMENT
    DEFAULT_RAM                                                               INTO RAM;
    DEFAULT_ROM, ROM_VAR, STRINGS                        INTO ROM;
    directPAGE                                                                      INTO Z_RAM;

END

I also confirm that all my directPAGE variable doesnt exceed the allocation.

Thanks

Re: DATA_SEG doesnt work as written

CompilerGuru — Sat, 02 Jun 2007 01:11:03 GMT

Are the variables in directPAGE actually allocated in the zero page?

I see a problem in your code that the #pragma DATA_SEG does not have a SHORT_SEG qualifier. Placing any variables in the prm file into the zero page works, but it wont cause that the compiler is using direct addressing unless you allow the compiler to do that with an explicit SHORT_SEG qualifier.
So please try this pragma instead:

#pragma DATA_SEG SHORT_SEG directPAGE

Daniel

Re: DATA_SEG doesnt work as written

sureshkumar — Sun, 10 Jun 2007 14:13:19 GMT

Thanks, Its work now. Its that possible if you can explain a further what is SHORT_SEG means in pragma means. Thanks again.

Suresh

Re: DATA_SEG doesnt work as written

CrasyCat — Mon, 11 Jun 2007 16:52:07 GMT

Hello

I assume you are using CodeWarrior for HC08 V5.1 or V5.0.

Please take a look at {Install}\Help\PDF\Compiler_HC08.pdf,

Chapter "Using the Compiler", section "Compiler Pragmas" -> "Pragma Details" -> "#pragma DATA_SEG: Data Segment definition" provides you with more information on what _SHORT_SEG is doing.

Chapter "Using the Compiler", section "HC(S)08 Backend" -> "Call Protocol and calling Convention" -> "Segmentation" provides additional information around that.

I hope it helps.

CrasyCat

Re: DATA_SEG doesnt work as written

sureshkumar — Thu, 14 Jun 2007 12:51:58 GMT

Thanks Crasy. I will browse it.