Machine language on the iSeries has always been a bit of a mystery. And rightfully so for OS/400 users, who have no direct access to machine language or the machine language compiler, called assembly language, through normal development tools.
However, Linux users do sometimes need to dig into machine language and have an understanding of the assembly language syntax and tools that Linux uses internally to translate C programs into executable form. IBM software developer Hollis Blanchard fills the gap with the excellent tutorial "Introduction to Assembly on the PowerPC."
The tutorial provides an overview of PowerPC architecture, the Application Binary Interface, and examples of situations requiring machine language programming (such as the need to access machine registers or to implement I/O drivers). Blanchard includes example programs and a valuable list of pointers to more detailed machine programming information.
The tutorial is online at IBM's developerWorks Web site: