256kB RAM am Mega128??

#define EXT_PAR_BEG  0x7100
//Beginn of the parameter memory
#define EXT_PAR_MEM(address) (EXT_PAR_BEG + address)

int msg_rd_no_org        @EXT_PAR_MEM(0x00);
char rd_off_ptr_org      @EXT_PAR_MEM(0x02);
unsigned int rd_ptr_org  @EXT_PAR_MEM(0x03);

Geht auch eleganter, aber fuer meinen Zweck OK

Geht natuerlich auch per pointer

unsigned char *par_ram_ptr;
unsigned char test;
unsigned char test1;

par_ram_ptr = (unsigned char*)EXT_PAR_BEG;
                            test = *par_ram_ptr;

par_ram_ptr++;
test1 = *par_ram_ptr;