On Tue, Aug 23, 2005 at 07:16:02PM +0200, Jan Hudec wrote: > On Tue, Aug 23, 2005 at 18:23:23 +0200, Garcia Jérémie wrote: > > So how do I have to compile the module file (.c) and the assembler file (.S) : separatly or not? with what compile options? > > Cause if I declare in my "module.c" the assembler function as "extern" how the link is done? > > Please give some clues cause I do not have much time to achieve this... > > Gcc compiles C to assembly. From which point they are both treated the same. > > Now each assembly is assembled to object separately. It is always the case, > even if you call gcc with multiple source arguments. So there is no question > there. > > The options are the same as when compiling C. Some options could be omitted, > as they apply to the compilation proper, but gcc will ignore them if you pass > them, so you can just pass the same options to all sources. > > As they are different sources, you need to declare symbols you need from the > other as extern. Note, that extern on function declaration has no effect, as > function declarations are extern by default. > > There is a bunch of assembly sources in kernel sources, in the arch > directory, so have a look how the kernel Makefile handles them and how the > symbols from them are accessed. Also note that using assembly in drivers is a *very* bad idea cause it makes the code non-portable. Until two years ago you could blissfully ignore this and think "all the world is a 386", but with the number of x86_64 machines growing every day this is no longer true. Face it, Athlon64 machines are a reality. Right now there are exactly *four* drivers that have an assembly part, but all those drivers are for hardware that's intimately tied to a certain architecture. Unless the OP has such hardware, there's no reason to write a (part of a) driver in assembly. Erik -- Erik Mouw J.A.K.Mouw@xxxxxxxxxxxxxx mouw@xxxxxxxxxxxx
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