Reference Guide

Chapter 3 51
HP-UX Architecture Conventions
Shared Libraries
Shared Libraries
The field selectors T', LT', and RT' are used to write
position-independent code in assembly language. When you use these
selectors and invoke the Assembler with the as command, you must use
the +z or +Z compiler option on the command line.
Any assembly code that is to be used with shared libraries must follow
the standard procedure call mechanism as defined in the runtime
architecture documents under the topic PA-RISC Architecture at URL:
http://www.software.hp.com/STK/. Any external procedures must be
exported as type ENTRY for the shared library interface to work correctly.
For more information on position-independent code and shared libraries,
refer to the HP-UX Linker and Libraries Online User Guide and the ELF
64 Object File Format, URL: http://www.software.hp.com/STK/.
Assembly Listing
The Assembler command-line option, -l, causes an assembly listing to
standard output. For each line of source code, the listing provides:
• line number
• the subspace offset
• the hexadecimal representation of the assembled code (possibly
flagged with an asterisk (*) to indicate address relocation)
• the source text
• any comments.
The following is a line of assembly language as it appears in the source
file:
SAVE LDO VAL(%r0),%r20 ;retain value
The above line would appear in the assembly listing as follows:
line no. offset hex representation label opcode operands comment
16 0000004c (341400A) SAVE LDO VAL(%r0),%r20 ;retain value