ARM gas ld question

Strip the problem to minimal sources showing the effect, post the sources, link map and objdump result.

OK, I'll shrink the sources and post. One other bit of information is that the branch instructions do work for the ARM instruction set, just not for the thumb. i.e. replacing code 16 with code 32 in the assembler sources, and removing the -thumb when assembling with gas.

Maybe you're missing .thumb_func from the targets.

For an example, see the code generated by ARM GCC with -mthumb -S.

Thanks for the response.

I did not have the .thumb_func directives in my sources. I have just put them in, now if I use 'bl' instructions, then the dissassembly shows correct branch addresses. However, 'b' instructions still behave as before. As it happens I can use 'bl' to get my code working for now so at least I can get on with what I'm doing - thanks for the tip Tauno.

It would be nice to know how to get the 'b' instruction working, I guess there is another directive missing. I have done a google search looking for an example of using the thumb instruction set with GNU tools but haven't found anything - that's what I could really do with.

I have looked at the output of gcc and have tried the '.type function_name,function' directive, but this doesn't sort the branch problem. This directive is not needed for the 'bl' instruction. All that was required here was the .thumb_func directive just before the label of the function being branched to.

Thx

Note: bl and b have different possible branch distances in Thumb. Maybe the branch and the destination are too far from each other ? (The linker should report an error, but maybe there is a bug !?)