2008/4/5, Brian Dessent <brian@xxxxxxxxxxx>: > Dennis Wassel wrote: > > > I've been trying to compile the ATLAS library on an 32-bit Linux > > system with my self-compiled gcc 4.3.0, but this fails. > > It boils down to the ATLAS config utility noticing that I have a > > 64-bit processor and trying to compile some low-level stuff with -m64, > > which doesn't work because I have not compiled in 64-bit support. [I > > could force 32-bit mode, but I feel that 64-bit mode surely improves > > performance, which is what ATLAS is for in the first place] > > > You could build a cross compiler, but what would be the point? You're > running a 32 bit operating system which means you can't run 64 bit > binaries, even if you have a processor capable of doing so. The > resulting output would be totally useless. As Andrew said it only works > in the other direction. > > It is also possible to build a native gcc that supports -m64 on a 32 bit > host. To do so requires first installing the 64 bit libc headers and > libraries in the appropriate places (normally done through your distro's > package manager) as well as an x86_64 binutils in the same prefix and > then using --enable-targets=all when configuring. If you're not root > this will likely be impossible since you can't write to /usr/lib64 or > whatever, so you'll have to go with the cross-compiler method. But > again, simply switching to a 64 bit operating system is what is actually > required here since then gcc will generate 64 bit binaries by default, > and you'll actually be able to run the resulting binary. > > > Brian > I've had a feeling that a cross-compiler is what I need -- you confirm that, thanks a lot! What strikes me about this is the fact that ATLAS' configure (all by itself, no options given) thinks that using -m64 on a 32-bit system might be a good idea (not to actually link something executable, probably just some low-level assembler-ish stuff, no clue), since I'm using a 64-bit compiler - am I up to something here, or do you think it's just One Of Those Things? Dennis
