Over bij Thresh's FiringSquad hebben ze een guide in elkaar geflanst over de Intel Itanium IA-64 processor (voorheen Merced). Hieronder heb je vast een gedeelte, lees de rest van het verhaaltje hier.
One of the greatest complaints about Intel's 32-bit processors was a lack of registers. Intel calls IA-64 "Massively Resourced", which means they have finally brought their architecture to the level of resources offered by other modern CPU's. The Itaniums will ship with 128 Integer/Multimedia registers, 128 82-bit Floating Point registers, 64 predicate registers, and 8 Branch Registers. The large number of registers have allowed Intel to integrate a dynamic register stack engine, which should greatly increase the performance of multitasking applications.
All multitasking is performed by giving each program a slice of CPU time. When one programs slice is over and another one has begun, it is called a context switch. Most processors are forced to save their registers to memory before allowing the next program access; otherwise, the data used by the previous program will be overwritten. The IA-64 will instead dynamically allocate registers every time there is a context switch. The compiler will add an alloc (allocation) command to each program that asks for a number of registers to use. The CPU will rename a number of its registers and give them for that program to use. When its time for another program to use the processor, instead of saving data to memory, the Itanium renames its registers to offer the next program a clean set. When the first program switches back, the CPU renames the registers again the data is there for use; no slow memory accesses necessary.