APPLICATION REGISTER SET AND APPLICATION REGISTER STATE

The Itanium architecture provides a set of for programmers to use in their applications. With this large number of internal registers available, several computations can be performed at the same time without having to frequently store (write) and load (read) intermediate results to or from memory. This is an important asset of the architecture and contributes to the high level of software performance achieved by the architecture.

Figure 3.1 shows the processor s register files. They include 128 general registers, the instruction pointer, 128 floating-point registers, 64 predicate registers, 8 branch registers, a current frame marker register, user mask register, processor identifier registers, performance monitoring data registers, and up to 128 special purpose registers called the application registers. This chapter examines all but the floating-point registers. Chapter 9 covers the floating-point resources of the application architecture.

Figure 3.1: Application Register Set

The application register state of the Itanium architecture represents the current contents of the registers that are affected by the execution of an application. The values in these registers can be saved, read, or modified by the programmer using instructions. The application register state does...