The 64-bit environment addresses an increasing demand for larger storage requirements and greater processing power. AIX Version 4 Release 3 provides an environment that allows you to develop and execute programs that exploit 64-bit processors through the use of 64-bit pointers and 64-bit integers. AIX 4.3 and above is required to load 64-bit object modules.
To support larger executables that can be fit within a 64-bit address space, a new object format has been created to meet the requirements of 64-bit executables. The binder binds 64-bit objects to create 64-bit executables. Note that objects that are bound together, statically or shared, must all be of the same object format. The following scenarios are not permitted, and will fail to load or execute or both:
On both 64-bit and 32-bit platforms, 32-bit executables will continue to run as they currently do on a 32-bit platform.
The XL Fortran compiler mainly provides 64-bit mode support through the compiler option -q64, in conjunction with the compiler option -qarch. This combination determines the bit mode and instruction set for the target architecture. The -q32 and -q64 options take precedence over the setting of the -qarch option. Conflicts between the -q32 and -q64 options are resolved by the "last option wins" rule. Setting -qarch=com will ensure future compatability for applications, whereas the rs64a, rs64b, pwr3, and auto settings will be more system-dependent.