HPPA / PA-RISC Architecture Documentation

The Hewlett Packard Precision Architecture is used in all systems running the HP-UX operating system. It was developed in the 1980'ies by Hewlett Packard and is the result of extensive research in the field of RISC microprocessors. Later the HP labs have branched their work on RISC processors and worked together with Intel to create the EPIC based IA64 architecture. Over the long run HP-UX and HPPA will be replaced using IA64 based systems, but nowadays a lot servers and workstations especially in the educational, military and government sector still run systems of this type. A few years ago Linux and NetBSD have been ported to HPPA and provide the only free operating systems beside HP-UX. Nobody would want to run anything but HP-UX on such a beast anyway.

File	Size	Description	Source
HPUX 10.20 Runtime Architecture Document v3.0 (pdf)	1085 kb	ABI and other low level HP-UX related information (for HP-UX 10.20)	Hewlett Packard
HPUX 11.0 Runtime Architecture Document v1.0 (pdf)	559 kb	ABI and other low level HP-UX related information (for HP-UX 11.0)	Hewlett Packard
HP Assembler Reference Manual HP9000 9th Edition (pdf)	329 kb	Assembler directives and options, also covers helpful low level info about HP-UX default memory layout	Hewlett Packard
PA-RISC 1.1 Architecture and Instruction Set Reference Manual 3rd_Edition (pdf)	1347 kb	PA-RISC CPU reference and instruction set	Hewlett Packard

There is plenty of additional information available. The PA-RISC Linux Documentations are a nice compilation of documents. Another good resource where the documents above have been taken from is the Hewlett Packard Documentation server. I wanted to include the PA-RISC 2.0 specifications in here, too, but HP only offers them online, so if you need them, take a look here.