Page 369 - Programming Microcontrollers in C

354 Chapter 7 Advanced Topics

Here the least significant byte of data is assigned to the smaller ad­
dress and the most significant byte goes to the larger address. Almost
all Motorola chips use big endian, and almost all Intel chips use little
endian. There can be some confusion when developing code to run
on one style of data storage on a machine with the opposite. This
problem is seen in the following program.
#include <stdio.h>

main()
{
unsigned array[25];
int i;

numbdup(“123456789098765”,array,25);
for(i=0;i<8;i++)
printf(“%x”,array[i]);
putchar(‘\n’);
}

Listing 7-2: Numeric Encode Test
If this program is compiled with a PC (Intel-based) compiler, the
result will not appear to be correct. However, if the program is com­
piled on an HC12, or 68HC16, or 683XX, or 68HC11, or 68HC05
compiler, it will seem to work correctly. In fact, both results are cor­
rect, only the numeric representation in memory is different.

Numeric Decoding
Once the numeric data are encoded and stored, they must be de­
coded to be used by other parts of the program. The decode routine
is called putbcd(). This function is shown below.

void putbcd(char *s,char *number)
{
int c,i=0;
char *sa;
sa=s;
while(*sa!=’\0')
{