RealView Compilation Tools Compiler Reference Guide - ARM ...

Compiler-specific Features
In particular, variables explicitly initialized to zero are placed in RW not ZI. Such
variables are not candidates for the ZI-to-RW optimization of the compiler.
• Uninitialized variables are placed in a section with type ZI.
Note
This variable attribute is not supported by GNU compilers.
Syntax
__attribute__((at(address)))
Where:
address
is the desired address of the variable.
The keyword __at comes immediately after the variable name.
Restrictions
The linker is not always able to place sections produced by the at variable attribute.
Errors
The linker gives an error message if it is not possible to place a section at a specified
address.
Example
const int x1 __attribute__((at(0x10000))) = 10; /* RO */
int x2 __attribute__((at(0x12000))) = 10; /* RW */
int x3 __attribute__((at(0x14000))) = 0; /* RW, not ZI */
int x4 __attribute__((at(0x16000))); /* ZI */
See also
• Using __at sections to place sections at a specific address on page 5-37 in the
Linker Guide.
4.5.3 __attribute__((aligned))
The aligned variable attribute specifies a minimum alignment for the variable or
structure field, measured in bytes.
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