ARM Compiler toolchain Using the Linker - ARM Information Center

8.19 Using __at sections to place sections at a specific address
8.19.1 See also
Using scatter files
You can give a section a special name that encodes the address where it must be placed. You
specify the name as follows:
.ARM.__at_address
Where:
address is the required address of the section. You can specify this in hexadecimal or
decimal. Sections in the form of .ARM.__at_address are referred to by the
abbreviation __at.
In the compiler, you can assign variables to __at sections by:
• explicitly naming the section using the __attribute__((section(”name”)))
• using the attribute __at that sets up the name of the section for you.
; place variable1 in a section called .ARM.__at_0x00008000
int variable1 __attribute__((at(0x8000))) = 10;
Example 8-10 Assigning variables to __at sections
; place variable2 in a section called .ARM.__at_0x8000
int variable2 __attribute__((section(".ARM.__at_0x8000"))) = 10;
Note
When using __attribute__((at(address))), the part of the __at section name representing
address is normalized to an 8 digit hexadecimal number. The name of the section is only
significant if you are trying to match the section by name in a scatter file. The linker
automatically assigns __at sections when you use the --autoat command-line option. This
option is the default.
Concepts
• Placing functions and data at specific addresses on page 8-18
• Using __attribute__((section("name"))) on page 8-35
• Restrictions on placing __at sections on page 8-38
• Automatic placement of __at sections on page 8-39
• Manual placement of __at sections on page 8-41
• Placing a key in flash memory using __at on page 8-42
• Placing a structure over a peripheral register using __at on page 8-43.
Reference
Linker Reference:
• --autoat, --no_autoat on page 2-17.
Compiler Reference:
• __attribute__((section("name"))) function attribute on page 5-53
• __attribute__((at(address))) variable attribute on page 5-67
• __attribute__((section("name"))) variable attribute on page 5-72.
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