Florent DEFAY <spira.inhabitant@xxxxxxxxx> writes: > First, there are 2 libgcc : libgcc1 and libgcc2. What is the difference ? libgcc1 exists primarily conceptually. It is the basic set of operations which can not be reasonably implemented using other operations. In the good old days libgcc1 was built using the other compiler on your system. Since these days there is generally no other compiler, most targets provide assembler code to perform the operations. For example, see config/arm/lib1funcs.asm. libgcc2, conversely, is the set of operations which can be implemented reasonably. For example, if you have a 32-bit add instruction, it's easy to use it to implement 64-bit addition. This code appears in gcc/libgcc2.c. On many processors it is possible to optimize using instructions which are not avaliable in C, such as add-with-carry; those optimizations are written in gcc/longlong.h. > When reading GCC Internals, I found information about libgcc2 and I > tried to insert the following line in the t-target : > > LIB2FUNCS_EXTRA=mulhi3.S > > where mulhi3.S contains the assembler code for the function __mulhi3. mulhi3 would be in libgcc1, not libgcc2. You would normally set LIB1ASMSRC and LIB1ASMFUNCS. > When building GCC, no rule to compile mulhi3.S Well, no. You have to write it yourself. > Then I tried this (just like msp430) : > > LIB1ASMSRC = target/mulhi3.S > LIB1ASMFUNCS = __mulhi3 Looks right, assuming you've written mulhi3.S. > Moreover, when building GCC, it finishes with this error : > *** Configuration target-unknown-none not supported > make[1]: *** [configure-target-libgcc] Error 1 > make[1]: Leaving directory `/home/me/gcc/build_target' > make: *** [all] Error 2 This is why libgcc wasn't built. You need to patch gcc/config.gcc to support your target. Actually I don't know how you would have gotten this far without doing that, so there may besomething else you need to do. > I searched about this error. I found a reply. It says "sym-link newlib > into GCC sources". That's if you want a C library. You haven't gotten to that point. It won't help with this problem. > This is the same, I am not intrested in libstdc++, how to disable that? Run configure with --enable-languages=c. Ian
