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(ld.info)MEMORY

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MEMORY command
==============

   The linker's default configuration permits allocation of all
available memory.  You can override this by using the `MEMORY' command.

   The `MEMORY' command describes the location and size of blocks of
memory in the target.  You can use it to describe which memory regions
may be used by the linker, and which memory regions it must avoid.  You
can then assign sections to particular memory regions.  The linker will
set section addresses based on the memory regions, and will warn about
regions that become too full.  The linker will not shuffle sections
around to fit into the available regions.

   A linker script may contain at most one use of the `MEMORY' command.
However, you can define as many blocks of memory within it as you
wish.  The syntax is:
     MEMORY
       {
         NAME [(ATTR)] : ORIGIN = ORIGIN, LENGTH = LEN
         ...
       }

   The NAME is a name used in the linker script to refer to the region.
The region name has no meaning outside of the linker script.  Region
names are stored in a separate name space, and will not conflict with
symbol names, file names, or section names.  Each memory region must
have a distinct name.

   The ATTR string is an optional list of attributes that specify
whether to use a particular memory region for an input section which is
not explicitly mapped in the linker script.  As described in Note:
SECTIONS, if you do not specify an output section for some input
section, the linker will create an output section with the same name as
the input section.  If you define region attributes, the linker will use
them to select the memory region for the output section that it creates.

   The ATTR string must consist only of the following characters:
`R'
     Read-only section

`W'
     Read/write section

`X'
     Executable section

`A'
     Allocatable section

`I'
     Initialized section

`L'
     Same as `I'

`!'
     Invert the sense of any of the preceding attributes

   If a unmapped section matches any of the listed attributes other than
`!', it will be placed in the memory region.  The `!' attribute
reverses this test, so that an unmapped section will be placed in the
memory region only if it does not match any of the listed attributes.

   The ORIGIN is an expression for the start address of the memory
region.  The expression must evaluate to a constant before memory
allocation is performed, which means that you may not use any section
relative symbols.  The keyword `ORIGIN' may be abbreviated to `org' or
`o' (but not, for example, `ORG').

   The LEN is an expression for the size in bytes of the memory region.
As with the ORIGIN expression, the expression must evaluate to a
constant before memory allocation is performed.  The keyword `LENGTH'
may be abbreviated to `len' or `l'.

   In the following example, we specify that there are two memory
regions available for allocation: one starting at `0' for 256 kilobytes,
and the other starting at `0x40000000' for four megabytes.  The linker
will place into the `rom' memory region every section which is not
explicitly mapped into a memory region, and is either read-only or
executable.  The linker will place other sections which are not
explicitly mapped into a memory region into the `ram' memory region.

     MEMORY
       {
         rom (rx)  : ORIGIN = 0, LENGTH = 256K
         ram (!rx) : org = 0x40000000, l = 4M
       }

   Once you define a memory region, you can direct the linker to place
specific output sections into that memory region by using the `>REGION'
output section attribute.  For example, if you have a memory region
named `mem', you would use `>mem' in the output section definition.
Note: Output Section Region.  If no address was specified for the
output section, the linker will set the address to the next available
address within the memory region.  If the combined output sections
directed to a memory region are too large for the region, the linker
will issue an error message.