After you use MEMORY to specify the target system's memory model, you can use SECTIONS to allocate output sections into specific named memory ranges or into memory that has specific attributes. For example, you could allocate the .text and .data sections into the area named RAM1 and allocate the .ebss section into the area named PROG.

The SECTIONS directive controls your sections in the following ways:

• Describes how input sections are combined into output sections
• Defines output sections in the executable program
• Allows you to control where output sections are placed in memory in relation to each other and to the entire memory space (Note that the memory placement order is not simply the sequence in which sections occur in the SECTIONS directive.)
• Permits renaming of output sections

For more information, see Section 3.6, Section 3.8, and Section 3.5.6. Subsections allow you to manipulate sections with greater precision.

If you do not specify a SECTIONS directive, the linker uses a default algorithm for combining and allocating the sections. Section 9.8 describes this algorithm in detail.