Imagecraft c compiler and development environment for the atmel avr

ICCV8 for AVR – C Compiler for Atmel AVRLinker OperationsThe main purpose of the linker is to combine multiple object files into an output filesuitable to be loaded by a device programmer or target simulator. The linker can alsotake input from a “library,” which is basically a file containing multiple object files. Inproducing the output file, the linker resolves any references between the input files. Insome detail, the linking steps involve:1. Making the startup file be the first file to be linked. The startup file initializes theexecution environment for the C program to run.2. Appending any libraries that you explicitly requested (or in most cases, as wererequested by the IDE) to the list of files to be linked. Library modules that aredirectly or indirectly referenced will be linked in. All the user-specified object files(for example, your program files) are linked.3. Appending the standard C library libcavr.a to the end of the file list.4. Scanning the object files to find unresolved references. The linker marks theobject file (possibly in the library) that satisfies the references and adds to its list ofunresolved references. It repeats the process until there are no outstandingunresolved references.5. Combining “areas” in all marked object files into an output file and generating mapand listing files as needed.Lastly, if this is the ADVANCED or PROFESSIONAL version and if the CodeCompressor (tm) optimization option is on, then the Code Compressor is called.Memory AllocationAs the linker combines areas from the input object files, it assigns memory addressesto them based on the address ranges passed in from the command line (see LinkerArguments). These arguments in turn are normally passed down from the IDE basedon the specified device. That is, in the normal case, you do not need to do anythingand the IDE/compiler will do the correct memory allocation for you.If you use #pragma text / data / lit / abs_address to assign your ownmemory areas, you must manually ensure that their addresses do not overlap theones used by the linker. As an attempt to overlap allocation may or may not cause thelinker to generate an error, you should always check the .mp map file (use the IDEmenu selection View->Map File) for potential problems.191