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3 - Programming a microcontroller
03-link
3.1.2.4 The project builder/make utility
In the process introduced above, that relies on splitting-up the processing to save time, it is im-
portant to keep track of which sources have been altered, only re-assemble these and not the
others and then link all the object files. Forgetting to do this may waste a lot of time. For ex-
ample, after making a correction, if a program still shows the same incorrect behavior as pre-
viously, one is tempted to suspect another part of the code. Trying to identify which other part
of the program produced the problem will be a useless effort, if the real reason was that the file
containing the change had not been re-assembled and linked.
Thus, a tool that can guarantee that the programmer will never forget to reprocess his files is
an invaluable help. This tool is called Maker or Make utility.
The maker is a tool that works under the control of a file that gives the names of the source
files, the name of the output object file, the names of the tools needed to process a file to an-
other file (assembler, linker), and the dependency relationships between the files.
For example, the dependency relationships specify that the final object file is produced by ap-
plying the linker tool to the files named in the linker control file; that each of the individual ob-
ject files is produced by applying the assembler tool to the corresponding source file, etc.
The maker works as follows:
File2.obj
Relocatable object files
File.cod
or
File.abs
File.map
Absolute object file
Map file
Linker invocation
File1.obj
File3.obj
Linker
File.sym
Symbol table
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