CY, Axiom was ported to the Zaurus handheld using cross-compilation. Camm does it in the Debian setup.
There are two methods generally used, CROSS-COMPILATION and CROSS-MOUNTING. CROSS-COMPILATION involves two systems, B -- the build system and T -- the target system. You compile on B but tell GCC that the target is T. GCC is designed in layers. The source code eventually gets compiled to RTL (Register Transfer Language) which is a target independent lisp-like assembler language. Since this is system-independent you can use the RTL anywhere. The final stage of GCC compiles RTL to the target platform. GCC currently targets about 20 platforms. This is useful for targets like the Zaurus (an ARM (i386-ish) processor) that do not have the horsepower to be a compile platform. It is also useful for embedded systems. CROSS-MOUNTING is easier if the target system has the tools and horsepower to host GCC. For instance, to build on a Sun system it is easier to use NFS (Network File System). Here we talk about S -- the source system and T -- the target system. On S, which contains the source tree, you 'export' the filesystem using NFS. This allows anyone to mount the filesystem remotely. On T you NFS-mount the sources. They now appear to be on the target system and you can just type 'make' Axiom can use this system. First you build on S so that you have a full build tree (SRC, INT, OBJ, MNT). Notice that these are defined as SRC -- Human created, read-only INT -- Machine-generated, Machine-independent OBJ -- Machine-generated, Machine-dependent MNT -- Final distribution tree SRC contains the source tree. NFS export on B it so it can be mounted on T. INT contains a 'cache' of extracted code that is system-independent so it also can be NFS exported on B and NFS-mounted on T. This saves having to redo a lot of work. On B you export SRC & INT. On T you NFS-mount SRC & INT. On T you set the AXIOM variable to the local machine (e.g. export AXIOM=`pwd`/mnt/sun) On T you type 'make' and it builds a Sun version. In parallel, other systems can also do NFS-mount and make. The only change is the AXIOM variable (e.g. `pwd`/mnt/macox) The advantage of CROSS-COMPILATION is that you can build for systems that don't support a build environment. The disadvantage is that you need a cross-compiled environment (e.g. libraries need to be cross compiled, .h files need to reflect the target, etc.). Since Axiom needs the X11 libraries for a full build you need to have X11 libraries that are cross-compiled for the target (e.g. Zaurus) The advantage of CROSS-MOUNTING is that you are building on the final target and can use all of the libraries, includes, and tools. The disadvantage is that you can't do this if the target does not have the horsepower. Which method you use is determined by the resources of the target. t _______________________________________________ Axiom-developer mailing list Axiom-developer@nongnu.org http://lists.nongnu.org/mailman/listinfo/axiom-developer
