ALPHA 21164 PC Alpha 21164 PC Highperformance alternative

ALPHA 21164 PC

Alpha 21164 PC High-performance alternative to a Windows NT Personal Computer

21164 Alpha Chip • One of the highest performing microprocessor • speeds topping one billion instructions per second • quad-issue and superscalar in architecture

Advantages • speed factor • manufacturing systems with greater simplicity • manufacturing systems with lower cost • run at a low voltage rate of 3. 3 volts • runs on various platforms such as both UNIX and windows

Advanced Structure • virtual instruction caching • seven-bit address space numbers • on chip dual read ported data cache out of order instruction completion • on chip three way set instruction completion • third level cache parameters

Some Design Goals • • reduced cost higher performance reduced power time to market

Reduction Factors • Required two elements – die size reduction – remove processing steps

Layout conversion strategy • Thirty percent linear shrink was not feasible • to compensate 25% linear shrinkage was used

Speed How fast do you want to go today? 400 Mhz, 466 mhz, or 533 Mhz

Speed Design • based upon a single-wire two phase clocking plan • 14 gates per cycle including the latches • single global clock grid (global clock skew<90 ps, local clock skew<25 ps)

Initial Conversion Problems • most programs had to be converted before they could be run on an alpha system • This was because the alpha processor was designed as a 64 bit system when it came out, and all of the other systems on the market were still 32 bit • This caused a problem with running the ‘standard’ 32 bit programs on a 64 bit processor

Conversion Solution • had to come up with software that could covert a 32 bit program to run on a 64 bit machine. • used a program called FX!32

The Chip • • • 0. 5 micrometer CMOS process Operation frequency of 300 MHz 5 functional units 3 cache memory 9. 3 Million transistors VLSI - Very Large Scale Integration

Registers • Standard Registers • Program Counter • Stack Pointer • Process Status • Unique to the alpha 21164 • floating point register

The Cache Memory on the Chip

Cache Memory • Instruction Cache – 8 KB of first level cache • Data Cache – 8 KB of first level cache • Set-Associative Cache – 96 KB of second level cache – holds both instructions and data

The Five Functional Units on the Chip:

The Instruction Unit • Contains an 8 KB, direct-mapped instruction cache, an instruction prefetcher and associated refill buffer, branch prediction logic, and an instruction translation buffer (ITB). • The instructional unit retrieves commands from the cache, distributes them to the appropriate functional units, after resolving any conflicts. • It controls all program flow, interrupt handling, and controls all data bypasses and register file writes. • The cache consists of 32 byte blocks that contain virtual address information.

Integer Unit • Used to execute all of the operation instructions that are to be performed on integers. • They receive their instructions from the instruction unit and direct their information to the appropriate pipelines.

The Floating-Point Unit • Used to execute all of the operation instructions that are to be performed on floating-point numbers. • They also receive all of their instructions from the instruction unit and send the correct information to the appropriate pipelines.

The Memory Unit • Contains a fully associative 64 -entry, data translation buffer, a direct mapped primary cache, the miss address file, and a write buffer. • Allows the system to store and access information

The Bus Interface Unit • This unit contains and manages the second level setassociative cache. • Allows the system interface to access the I/O and the memory.

Alpha 21164 PC 64 -bit Processor RISC

Alpha 21164 PC Superpipelined Superscalar

Alpha 21164 PC Other Technologies

ALPHA 21164 PC

Why Businesses Use Alpha Systems • • Exceptional internet services high-performance technical applications accomplish more work in less time greatly reduce their costs in man hours

Role in the Market Place Compaq Windows NT 5. 0 Outperforms TWO Pentium II’s Costs Less