AR refers to "armar" which is the ARM utility for creating libraries. FR refers to "fromelf" which is a tool for inspecting ELF objects and images, for converting them to other formats. I haven't got a copy of the example to hand, but I doubt it actually needs either.
Switch to GCC/GNU tools I foresee two problems. GAS (GNU assembler tool) and armasm (ARM's assembler tool) use different syntax. Which makes the .s files for one incompatible with the other. Meaning you'll have to port it. It's not too difficult (from limited past experience) but can be fiddly. Helps if you know one of the syntaxes well to start with.
THe other potential problem is libraries. The calls you make to set up and initialise the C library are different.
Many thanks for your helpful reply.
Great, I believe I can port the ARM .as files into the GNU .as files and I am aware of their major syntax differences.
Could you please provide more information about the issue of Libraries or route me to a helpful related document.
Thank you very much.
If you're lucky, you could use the C Pre-Processor in GNU as a wrapper around your ARM assembly files.
Say... You have foo.as and you want to assemble it using GAS; then wrap the C Pre-Processor aournd GAS for files ending in ".S"
To wrap GAS in the C Pre-Processor, use GCC with the '-x assembler-with-cpp' switch:
arm-none-eabi-gcc <some parameters> -x assembler-with-cpp <other parameters>
Make yourself an .S file like the following:
#define KEYWORD replacement
#define KEYWORDn replacement_n
... After all your #define macros, you can include your ARM-assembly file:
... or even ...
Of course, it will not handle all cases, so you may experience the need for modifying the .as files, so they will become "portable"
Also have a look at GAS's macros. They're quite powerful, and may be able to override keywords in your .as file too.