On Mon, Oct 3, 2011 at 4:47 PM, Michael LIAO <michael.hliao@xxxxxxxxx> wrote: > On Mon, Oct 3, 2011 at 4:03 PM, Mike Frysinger <vapier@xxxxxxxxxx> wrote: >> On Monday, October 03, 2011 18:57:28 Michael LIAO wrote: >> >> please don't top post >> > > sorry, it's my first post on mailing. > >>> Most examples would be related to tools generating code. >>> >>> Suppose you have a software package with several hard-coded fully >>> optimized assembly file for different targets. Your build system need >>> to know the current target as well as target ABI to select the correct >>> assembly file to build it. It even desirable if it includes a simple >>> script to help generate assembly code (like the one in OpenSSL), you'd >>> better know the target ABI to prepare proper glue code without >>> breaking ABI. >> >> hjlu posted examples to the x32 site as to handle this. the only difference >> between x86_64 and x32 is the size of the pointers. >> > > Besides the pointer size, there are other differences like indirect > branch which need different code sequence on x32 and x64. Indirect > branch would be used in assembly code (yeah, concrete example would > valuable here but indirect branch should be used potentially and > possibly in assembly code.) If the assembly code use indirect branch, > it needs to know the target ABI and generate/use difference code path. > In assembly codes, most, if not all, of x86-64 indirect branch work fine for x32 -- H.J. _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx https://lists.gnu.org/mailman/listinfo/autoconf
