ARM Compiler toolchain Using the Linker - ARM Information Center

Using scatter files
armcc -c -g function.c
armcc -c -g main.c
armlink --map 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__((at(0x5000))) specifies that the global variable gSquared is to be
placed at the absolute address 0x20000. gSquared is placed in the execution region
ER$$.ARM.__AT_0x00005000 and load region LR$$.ARM.__AT_0x00005000.
The memory map shows:
...
Load Region LR$$.ARM.__AT_0x00005000 (Base: 0x00005000, Size: 0x00000000, Max: 0x00000004, ABSOLUTE)
Execution Region ER$$.ARM.__AT_0x00005000 (Base: 0x00005000, Size: 0x00000004, Max: 0x00000004, ABSOLUTE,
UNINIT)
Base Addr Size Type Attr Idx E Section Name Object
0x00005000 0x00000004 Zero RW 15 .ARM.__AT_0x00005000 main.o
8.11.2 Example of placing a variable in a named section with scatter-loading
This example shows how to modify your source code to place code and data in a specific section
using a scatter file:
1. Create the source file main.c containing the following code:
#include
extern int sqr(int n1);
int gSquared __attribute__((section("foo"))); // Place in section foo
int main()
{
gSquared=sqr(3);
printf("Value squared is: %d\n", gSquared);
}
2. Create the source file function.c containing the following code:
int sqr(int n1)
{
return n1*n1;
}
3. Create the scatter file scatter.scat containing the following load region:
LR1 0x0000 0x20000
{
ER1 0x0 0x2000
{
*(+RO) ; rest of code and read-only data
}
ER2 0x8000 0x2000
{
main.o
}
ER3 0x10000 0x2000
{
function.o
*(foo) ; Place gSquared in ER3
}
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