- 64bit
root@Lab1 # file testmem
testmem: PA-RISC2.0 shared executable dynamically linked -not stripped
- 32bit
root@Lab1 # file /usr/bin/ls
/usr/bin/ls: PA-RISC1.1 shared executable dynamically linked

PA2.0 can support 64 bit and 32bit mode. an a.out can be as a 32 bit binary in PA2.0, if you complie it with +DA2.0 option.

If you complie with +DA2.0W then the a.out will be as 64bit binary in PA2.0

Summary compile options as
+DA1.1 - 32bit in PA1.1
+DA2.0 - 32bit in PA2.0
+DA2.0W - 64bit in PA2.0
===================================================
compile時的差異

- 64 bit
$ cc +DA2.0W a.c
$ file a.out
a.out: ELF-64 executable object file - PA-RISC 2.0 (LP64)

- 32 bit
$ cc +DA2.0 a.c
$ file a.out
a.out: PA-RISC2.0 shared executable dynamically linked -not stripped
$ cc +DA1.1 a.c
$ file a.out
a.out: PA-RISC1.1 shared executable dynamically linked -not stripped

參考資料：HP IT資源中心論壇