By default, the linker places unassigned sections using the following criteria:

If more than one .ANY selector is present in a scatter file, the linker takes the unassigned section with the largest size and assigns the section to the most specific .ANY execution region that has enough free space. For example, .ANY(.text) is judged to be more specific than .ANY(+RO).

If several execution regions are equally specific, then the section is assigned to the execution region with the most available remaining space.

For example:

You can give a priority ordering if you have multiple .ANY sections with the .ANYnum selector, where num is a positive integer from zero upwards. The highest priority is given to the selector with the highest integer.

The following example shows how to use .ANYnum:

lr1 0x8000 1024
{
    er1 +0 512
    {
        .ANY1(+RO) ; evenly distributed with er3
    }
    er2 +0 256
    {
        .ANY2(+RO) ; Highest priority, so filled first
    }
    er3 +0 256
    {
        .ANY1(+RO) ; evenly distributed with er1
    }
}

You can modify how the linker places unassigned input sections when using multiple .ANY selectors by using a different placement algorithm or a different sort order. The following command-line options are available:

Use first_fit when you want to fill regions in order.

Use best_fit when you want to fill regions to their maximum.

Use worst_fit when you want to fill regions evenly. With equal sized regions and sections worst_fit fills regions cyclically.

Use next_fit when you need a more deterministic fill pattern.

If the linker attempts to fill a region to its limit, as it does with first_fit and best_fit, it might overfill the region. This is because linker-generated content such as padding and veneers are not known until sections have been assigned to .ANY selectors. If this occurs you might see the following error:

Error: L6220E: Execution region regionname size (size bytes) exceeds limit (limit bytes).

The --any_contingency option prevents the linker from filling the region up to its maximum. It reserves a portion of the region's size for linker-generated content and fills this contingency area only if no other regions have space. It is enabled by default for the first_fit and best_fit algorithms, because they are most likely to exhibit this behavior.

The execution region attribute ANY_SIZE max_size enables you to specify the maximum size in a region that armlink can fill with unassigned sections.

Be aware of the following restrictions when using this keyword:

When ANY_SIZE is present, armlink:

ANY_SIZE does not require --any_contingency to be specified. However, when --any_contingency is specified and ANY_SIZE is not, armlink attempts to adjust contingencies. The aims are to:

If you specify --any_contingency on the command line, it is ignored for regions that have ANY_SIZE specified. It is used as normal for regions that do not have ANY_SIZE specified.

The following example shows how to use ANY_SIZE:

LOAD_REGION 0x0 0x3000
{
   ER_1 0x0 ANY_SIZE 0xF00 0x1000
   {
      .ANY
   }
   ER_2 0x0 ANY_SIZE 0xFB0 0x1000
   {
      .ANY
   }
   ER_3 0x0 ANY_SIZE 0x1000 0x1000
   {
      .ANY
   }
}

In this example: