Faqs >> Its about 32-bit Applications into 64-bit Application Compilling...solaris OS... UltaSparc processors...

(1) How can I tell which OS is running?

Use the isalist command to determine whether the machine is running the 32-bit or 64-bit operating system. If you are running the 64-bit operating system on an UltraSPARC machine, then isalist will list sparcv9 first:
% isalist
sparcv9+vis sparcv9 sparcv8plus+vis sparcv8plus sparcv8 sparcv8-fsmuld
sparcv7 sparc
If you are running the 32-bit operating system on a SPARC machine, then isalist will list sparcv7 or sparcv8 first:
% isalist
sparcv8plus+vis sparcv8plus sparcv8 sparcv8-fsmuld sparcv7 sparc

(2) Which option should I provide the compiler to generate 64-bit code? What is the difference between -xarch=v9, -xarch=v9a, and -xarch=v9b?

Using the Forte (WorkShop) C compiler, you specify the instruction set architecture (ISA) using -xarch.

• -xarch=v9 will generate 64-bit code.

• -xarch=v9a adds the Visual Instruction Set (VIS) and extensions specific to UltraSPARC processors to the SPARC-V9 ISA, and enables the compiler to generate code for good performance on the V9 SPARC architecture.

• -xarch=v9b adds UltraSPARC-III extensions and VIS version 2.0 to the V9a version of the SPARC-V9 ISA. Compiling with this option uses the best instruction set for good performance in a Solaris UltraSPARC-III environment.

Consult the Forte (WorkShop) documentation for detailed information.

Warning: Code compiled with -xarch=v9b will generate instructions unique to the UltraSPARC-III platform and thus cause errors on the UltraSPARCII platform. The

recommended option for generation of a 64-bit driver is -xarch=v9.

(3) Converter 32-bit Applications into 64-bit Applications : Things to Consider http://developers.sun.com/solaris/articles/ILP32toLP64Issues.html
(Developers Home > Sun Studio > Documentation > Sun Studio - Technical Articles & Tips )

(4) Selecting the Best Compiler Options
By Darryl Gove, Senior Performance Engineer, Sun Micro systems.
(SDN Home > Sun Studio > Documentation > Sun Studio - Technical Articles & Tips
http://developers.sun.com/solaris/articles/options.html