1. IA-64
Vincent D. Capaccio

2. IA-64 Overview Hewlett-Packard and Intel
EPIC - Explicitly Parallel Instruction Computing
64-bit width
Superscalar (Functional Units)
Predication (Pre-computing branches)
Speculation (Memory Hoisting)
X86 is the ISA for Pentium… IA-64 is the ISA for the Itanium.
Superscalar (parallel processing-functional units)
Predication – Predicting the outcome of a conditional statement. Load both and get both answers. Then choose which path to take depending on the answer.

3. EPIC Explicitly Parallel Instruction Computing
Smaller instruction set then RISC.
Room on chip for more functional units and registers.
Relies on Compiler to extract parallelism.

4. Functional Units (Superscalar)
Computations completed in Parallel
6 Arithmetic Logic Units (ALU’s)
6 Specialized Multimedia Functional Units
1 Floating-Point Functional Units

6. Registers 128 64-bit General Purpose Registers
r0-r31 are Static, r32-r127 are Dynamic
bit floating-Point Registers
f0-f31 are Static, f32-f127 are Dynamic
64 1-bit Predicate Registers
8 Branch Registers
At least 5 CUPID Registers

7. Predication (Pre-computing branches)
With x86 ISA - 20%-30% process performance is wasted on guessing which branch to take.
IA-64 takes BOTH paths (NO guessing)
Predicate registers are used to know which answer to throw away.

8. Speculation (Memory Hoisting)
Speculation is used to try to eliminate memory latency
IA-64 looks ahead in code are loads data before it is needed.

9. Questions?