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How to link const vars not referenced in source code, without modifying PRM file?

Question asked by Luciano Navarro on May 20, 2009
Latest reply on May 20, 2009 by Daniel Lundin

* Codewarrior 6.1 for microcontrollers

* S08AW60

* PRM file:  

SEGMENTS Z_RAM  =  READ_WRITE   0x0070 TO 0x00FF; RAM_A  =  READ_WRITE   0x0100 TO 0x025F; RAM_B  =  READ_WRITE   0x0260 TO 0x086F; ROM_A  =  READ_ONLY    0x1A00 TO 0x21FF; ROM_B  =  READ_ONLY    0x2200 TO 0xFFAF; ROM_C  =  READ_ONLY    0xFFC0 TO 0xFFCB; END PLACEMENT NVRAM           INTO  RAM_A; NVROM           INTO  ROM_A; DEFAULT_RAM     INTO  RAM_B; _PRESTART, ... DEFAULT_ROM     INTO  ROM_B; ...END

 

*C Source code:


unsigned char RAMVar1 @"NVRAM";unsigned char ROMVar1 @"NVROM"=0;unsigned char RAMVar2 @"NVRAM";unsigned char ROMVar2 @"NVROM"=245;...unsigned char RAMVar200 @"NVRAM";unsigned char ROMVar200 @"NVROM"=27;void InitNonVolatileVars(void){ unsigned char *pRAM; unsigned char *pROM; unsigned char n; n=__SEG_SIZE_NVRAM; pRAM=__SEG_START_NVRAM; pROM=__SEG_START_NVROM+LastCopyAddress(); do{*pRAM++=*pROM++;}while(--n);}void MyFunc(void)   { RAMVar1=RAMVar2;  ... }void SynchroRAM2ROM(void){...}

 

* Problem: ROMVars are not linked because they are not referenced in source code.

* Undesired solution: modify PRM file like this:

ENTRIES   ROMVar1   ROMVar2   ...   ROMVar200END

 

* Desired solution: modify source code like this:


unsigned char RAMVar1 @"NVRAM";__root unsigned char ROMVar1 @"NVROM"=0;unsigned char RAMVar2 @"NVRAM";__root unsigned char ROMVar2 @"NVROM"=245;...

 

I use "__root" for Atmel ATmega compiler, but I'd like the same code to run in Freescale's AW60:


#define __root __AlwaysLinkFreescale

How to do it?, is there a reserved word to tell the compiler and linker not to remove non referenced const vars?.

 

 

Thanks in advance

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