The optimizing linkage editor (Optlnk) used by the CC-RX provides the start option, which allows two or more sections defined in a program to be allocated to a single address. Sections that have been allocated in this way are called overlay sections.

This section describes how to set up the "overlay-section selection facility" for overlay sections in a load module.

When the program is executed, only one of the sections allocated to the same address in the load module is executed.

The debug tool provides the "overlay-section selection facility" to select a particular overlay section to be debugged preferentially (hereafter referred to as the priority section).

With the priority section selected before execution of the program, debugging of that section is simple because debugging information of other sections is hidden.

An example of using Optlnk's start option to define overlay sections is given below.

start = Psect01/1000,Psect02/2000,Psect03/3000,ram01:ram02:ram03/5000

rom = Psect01=ram01,Psect02=ram02,Psect03=ram03

The rom option reserves section "ramXX", which is as large as the "PsectXX" section, and relocates the symbols defined in the "PsectXX" section to the corresponding addresses in the "ramXX" section (XX: 01, 02, or 03 in this example).