On Mon, May 26, 2014 at 4:38 PM, Philip Guenther <[email protected]> wrote:
> On Mon, May 26, 2014 at 12:46 PM, sven falempin > <[email protected]>wrote: > >> documentation about this are ... sparse >> > > Intentionally. As far as the project is concerned, cross-compiling is for > bringing up a new platform, and that's about it. > > > >> # GENERIC.MP#315 amd64 >> TARGET_ARCH=i386 >> TARGET_CPU=geode >> TARGET=i386 >> # vi ./Makefile.cross >> # make -f ./Makefile.cross cross-distrib >> host and target have different size longs >> >> But gcc is able to target 32bit cpu from 64bit , so why this restriction ? >> Apparently the makefile even build the libc and everything so ... >> > > We experienced real cases where building when target and host had > different sizes resulted in bad code and lots of time wasted trying to > figure out what was wrong in the code, when the compiler was the problem. > Since there are fast archs for both 32 and 64, simply banning the mismatch > was a way to guarantee a known safe setup and stop developers from wasting > time on something gcc didn't support. > > To put it another way: let's say you disable that check and it all > *almost* works; if that build's problems resulted in other people wasting > time trying to figure out what went wrong, it would be a Very Bad Thing. > like those ? : https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31585 > > > I tried it because >> * qemu not so fast (still runing in background) >> * my i386 target very slow (and only 128mo ram) >> * do not want to install x86 on the build machine , currently thinking >> about dual boot >> x86/amd64 , i wonder if the amd64 boot could load a 32bit kernel... that >> would save the Active partition disk trick or the grub use. >> > > The i386 and amd64 boot blocks can load both types of kernel. I used to > do that until I accidentally toasted the second disk's install and switched > to building i386 on my old T60. > > > Philip Guenther > > Thank you, Is it possible to use this makefile to change the gcc version ? (for testing purpose) I read the makefile and saw static path to cc building a CROSSGCC , (i d like to use gcc 4.8) . -- --------------------------------------------------------------------------------------------------------------------- () ascii ribbon campaign - against html e-mail /\
