To avoid confusion, GCC outputs object code (after internally using the assembler) using the ELF format. It's a common problem due to the inexact nature of human language itself. Such as in this case, and Ahmed was clarifying. Note that it is common to refer to the whole process as "compiling" (as in GCC's name itself), but that then causes confusion when the specifics are discussed, Which effectively turns an elf into a bin, but purely in memory, for the CPU to run. Then one for the linker (which combines several object files into a single ELF file), and finally, at runtime, there is the dynamic linker, One for the compiler (which technically outputs assembly), another one for the assembler (which outputs object code in the ELF format), The (dynamic) linker first has to sufficiently reverse that (and thus modify offsets back to the correct positions).īut there is no linker/OS on the MCU, hence you have to flash the bin instead.Ĭompiling and linking are separate stages the whole process is called "building", hence the GNU Compiler Collection has separate executables: bin files as well as debugging linker scripts and other things that can help to mess up your bin or elf output.īin is the final way that the memory looks before the CPU starts executing it.ĮLF is a cut-up/compressed version of that, which the CPU/MCU thus can't run directly. Helps to overcome gnu problems in general creating. I recommend everyone writes an elf parsing program to understand what is in there, dont bother with a library, it is quite simple to just use the information and structures in the spec. The elf file format is a standard, arm publishes its enhancements/variations on the standard. Tells you how much binary you have and how much bss data is there that wants to be initialised to zeros (gnu tools have problems creating bin files correctly). Allows for more than one chunk of binary data (when you dump one of these to a bin you get one big bin file with fill data to pad it to the next block). You can take this data and load it directly as is, you need to know what the base address is though as that is normally not in there.Īn elf file contains the bin information but it is surrounded by lots of other information, possible debug info, symbols, can distinguish code from data within the binary. A bin file is just the bits and bytes that go into the rom or a particular address from which you will run the program.
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