Solution : https://service.sap.com/sap/support/notes/308375 (SAP Service marketplace login required)
Key words : 
64-bit-capable hardwarea basic requirement, 64-bit sap systemthe operating system upgrade, 64-bit software requires 64-bit-capable hardware, 32-bit sap kernel prepare   unpacks, directly access shared memory segments, 64-bit sap kernel ordatabase software, hp-ux operating system kernel, database upgrade guide describes, requires 64-bit itanium processors, installation tool r3setup isdelivered
Related Notes : 
       
| 1112627 | SAP on HP-UX: Recommendations for swap and pseudo swap | 
| 1075118 | SAP on HP-UX: FAQ | 
| 595304 | DB6: Availability of the 32bit kernel for Release 6.20 | 
| 548845 | Internal modes uses more than 2 GB | 
| 177724 | System copy with 64-bit R/3 kernel 4.5B (ORACLE) | 
| 172747 | SAP on HP-UX: OS kernel parameter recommendations | 
| 155355 | Installation SAP R/3 4.5B-64bit kernel | 
| 146289 | Parameter Recommendations for 64-Bit SAP Kernel | 
| 146248 | Installation SAP R/3 4.0B-64bit kernel | 
| 21960 | Several instances/systems on one UNIX computer |