On Tue, Mar 31, 2009 at 09:50:49PM -0500, Steve M. Robbins wrote: > Goswin, > > Thanks very much for the succinct lesson on biarch and multiarch. > > > On Wed, Mar 18, 2009 at 07:31:18PM +0100, Goswin von Brederlow wrote: > > > If you want to support 64bit (and n32) gmp on ppc, s390, sparc, mips > > and mipsel NOW then look at zlib as an example. > > Great. So I've gone through the zlib example in some detail, along > with the solutions provided by Matthias K. and Bill A. Inspired by > zlib, I figured I might as well build lib32xxx and lib64xxx wherever > possible, rather than just on amd64 and ppc, respectively. > > I'd greatly appreciate it if interested parties would have a look > at what I've done [1] and offer constructive criticism. > > I've run into a roadblock, however, in that the header gmp.h is > generated by configure. It has some parameters (size of a limb) that > depend on whether compiled for 32 or 64 bits. So on amd64, for > example, I have two incompatible gmp.h files. Matthias provided a > gmp.h wrapper from Redhat that selects between architecture variants > based on preprocessor symbols, e.g. > > #if defined(__i386__) > #include "gmp-i386.h" > #elif defined(__ia64__) > #include "gmp-ia64.h" > ...
I am surprised that I did not hit problems while using them. I suppose I always used long instead of mp_limb_t > However, in the case at hand it is the same architecture. Onqe > variant is compiled with -m32 and the other with -m64. Is there a > symbol that can distinguish the two so that I can use the Redhat > trick? Other solutions? Maybe gcc -m32 should be configured to look at /emul/ia32-linux/usr/include before /usr/include on amd64, so you could put the 32bit include files their. This seems the cleanest solution. > Incidentally, the zlib debian/rules uses "gcc -m64" on architectures > s390, sparc, i386, and powerpc. The info page on compiler options for > gcc 4.3, however, says: > > These `-m' switches are supported in addition to the above on AMD > x86-64 processors in 64-bit environments. > > `-m32' > `-m64' > Generate code for a 32-bit or 64-bit environment. The 32-bit > environment sets int, long and pointer to 32 bits and > generates code that runs on any i386 system. The 64-bit > environment sets int to 32 bits and long and pointer to 64 > bits and generates code for AMD's x86-64 architecture. For > darwin only the -m64 option turns off the `-fno-pic' and > `-mdynamic-no-pic' options. > > Does it really work to use -m64 on an i386? Does amd64 code result? Yes, though you might need to build-depend on gcc-multilib. Cheers, -- Bill. <[email protected]> Imagine a large red swirl here. -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
