ARM Compiler toolchain Using the Linker - ARM Information Center

8.13 Placing unassigned sections with the .ANY module selector
Using scatter files
The linker attempts to place input sections into specific execution regions. For any input
sections that cannot be resolved, and when the placement of those sections is not important, you
can use the .ANY module selector in the scatter file.
In most cases, using a single .ANY selector is equivalent to using the * module selector. However,
unlike *, you can specify .ANY in multiple execution regions.
8.13.1 Default rules for placing unassigned sections
By default, the linker places unassigned sections using the following criteria:
• Place an unassigned section in the execution region that currently has the most free space.
You can specify a maximum amount of space to use for unassigned sections with the
exection region attribute ANY_SIZE.
• Sort sections in descending size order.
8.13.2 Placement rules when using multiple .ANY selectors
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:
8.13.3 Prioritizing .ANY sections
• If you have two equally specific execution regions where one has a size limit of 0x2000
and the other has no limit, then all the sections are assigned to the second unbounded .ANY
region.
• If you have two equally specific execution regions where one has a size limit of 0x2000
and the other has a size limit of 0x3000, then the first sections to be placed are assigned to
the second .ANY region of size limit 0x3000 until the remaining size of the second .ANY is
reduced to 0x2000. From this point, sections are assigned alternately between both .ANY
execution regions.
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
{
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