ROM Tables on PIC184550

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Three things about 'const' arrays:

1. The compiler examines the arrays and if they have identical elements,
only the data for one array will be stored in ROM. One set of data will be
used for both arrays.

2. If an array is not referenced in your code, the compiler will not insert
the data into ROM.

3. If the array is accessed with constant values for the array indexes
(instead of a variable), the compiler may use MOVLW statements to
to load the array values, instead of putting the array into a table in ROM.

This is all done as part of optimizing (reducing) the ROM usage.