I have a C program which I want to benchmark on an (old) custom embedded platform. The problem is that I only have the hardware but not the toolchain to compile programs for this platform. The CPU is an Atmel AT91SAM9260 (ARM) and runs an embedded Linux to which I have full access. I have downloaded a program from the embedded system and analyse its format with 'readelf -h ...':
ELF Header:
Magic: 7f 45 4c 46 01 01 01 61 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: ARM
ABI Version: 0
Type: EXEC (Executable file)
Machine: ARM
Version: 0x1
Entry point address: 0x8520
Start of program headers: 52 (bytes into file)
Start of section headers: 3772 (bytes into file)
Flags: 0x602, has entry point, GNU EABI, software FP, VFP
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 6
Size of section headers: 40 (bytes)
Number of section headers: 25
Section header string table index: 24
Then I have written the following test program:
#include <stdio.h>
int main() {
printf("Hello World!\n");
return(0);
}
If I use the standard ARM cross-compiler in Ubuntu 12.04 (arm-linux-gnueabi-gcc test.c -o test), the wrong EABI is chosen (Version5 EABI instead of GNU EABI) and it doesn't run on the embedded system (access rights etc. are correct).
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: ARM
Version: 0x1
Entry point address: 0x8881
Start of program headers: 52 (bytes into file)
Start of section headers: 372148 (bytes into file)
Flags: 0x5000002, has entry point, Version5 EABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 7
Size of section headers: 40 (bytes)
Number of section headers: 30
Section header string table index: 27
If I use a bare metal compiler like Sourcery CodeBench I get errors like "undefined reference to...". This is clear because the stdlib is missing. I have tried to solve it by copying all lib-files from the embedding platform to the host and compile it with "./arm-none-eabi-gcc test.c -o test -static -lc -L ./lib". I still get (the same) undefined reference errors.
What is best practise to compile a C program for an embedded system if the toolchain is unknown?
