ARM Compiler toolchain Using the Linker - ARM Information Center

Using scatter files
RAM 0x200000 (0x1FF00-0x2000) ; RW & ZI data to be placed at 0x200000
{
*(+RW, +ZI)
}
ARM_LIB_STACK 0x800000 EMPTY -0x10000
{
}
ARM_LIB_HEAP +0 EMPTY 0x10000
{
}
}
The ARM_LIB_STACK and ARM_LIB_HEAP regions are required because the program is being
linked with the semihosting libraries.
4. Compile and link the sources:
armcc -c -g function.c
armcc -c -g main.c
armlink --map --scatter=scatter.scat function.o main.o -o squared.axf
The --map option displays the memory map of the image. Also, --autoat is the default.
In this example, __attribute__((section("foo"))) specifies that the global variable gSquared is
to be placed in a section called foo. The scatter file specifies that the section foo is to be placed
in the ER3 execution region.
The memory map shows:
Load Region LR1 (Base: 0x00000000, Size: 0x00001778, Max: 0x00020000, ABSOLUTE)
...
Execution Region ER3 (Base: 0x00010000, Size: 0x00000004, Max: 0x00002000, ABSOLUTE)
Base Addr Size Type Attr Idx E Section Name Object
0x00010000 0x00000004 Data RW 15 foo main.o
...
Note
If you omit *(foo) from the scatter file, the section is placed in the region of the same type. That
is RAM in this example.
8.11.3 Example of placing a variable at a specific address with scatter-loading
This example shows how to modify your source code to place code and data at a specific address
using a scatter file:
1. Create the source file main.c containing the following code:
#include
extern int sqr(int n1);
// Place at address 0x10000
const int gValue __attribute__((section(".ARM.__at_0x10000"))) = 3;
int main()
{
int squared;
squared=sqr(gValue);
printf("Value squared is: %d\n", squared);
}
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