A Short History of the PPC

Steve TerpeCS185C26 October 2011

PPC

Before 1991 PPC == Particle Projection Cannon

POWER PC ==

Performance Optimization With Enhanced RISC Performance Computing

MAD-5A Marauder II sporting 3 Extended Range PPCs

IBM's 601 circa 1992 first sported by Power Macintosh in 1994

Why bother? CISC vs. RISC

Early Computers kind of sucked... Programming done mostly in lower level

assembly languages...

Programming like thisIs very time consumingHow to make it more

Manageable?

A rich and extensive Instruction set!

What is a rich instruction set?

Have instructions that do as many things as possible at one time...

Consider the x86 add instruction: Usage: ADD dest,src Modifies flags: AF CF OF PF SF ZF Adds "src" to "dest" and replacing the original contents of "dest". Both operands are binary. Clocks Size Operands 808x 286 386 486 Bytes reg,reg 3 2 2 1 2 mem,reg 16+EA 7 7 3 2-4 (W88=24+EA) reg,mem 9+EA 7 6 2 2-4 (W88=13+EA) reg,immed 4 3 2 1 3-4 mem,immed 17+EA 7 7 3 3-6 (W88=23+EA) accum,immed 4 3 2 1 2-3

Problem...

Circa 1970's High level machine-

Compiled language have

Replaced assembly coding IBM's John Cocke >>

“father of RISC architecture” makes a key discovery...

All these compilers are really doing a dumb job.

Really dumb.

Machine compiled programs run inefficiently because the Computer doesn't know how to take best advantage of

suchA complex instruction set.

Cocke proposes what would become RISC architecture

My instruction Set is too

richfor you

You told the boss

my code sucks?

RISC

Reduced Instruction Set What is reduced exactly? —ambiguous language. What is not reduced is necessarily the

total number of instructions available to the machine.

What is reduced is the amount of work done by each instruction.

Reduced Instruction Sets

Sometimes called Load&Store because memory accesses are only allowed via specific Load & Store instructions.

X86 Instruction set allows you a lot of options when adding remember? A register or immediate value directly to memory address or another register or to the accumulator.

What does the add instruction look like on a RISC machine like a PPC?

RISC PPC Add

Add rD, rA, rB

RISC: So easy to choose even a cavemanCan do it.

Other Benefits

RISC instructions are smaller can be executed more quickly and are more easily pipelined.

This means that a RISC machine can perform more operations at a lower clock-speed while generating less heat than the comparably powered x86.

Marketing downside to this—consumers think PPCs are slow.

Origins of PPC

1991 AIM Alliance – founded on the principle of fighting the growing domination of Microsoft-Intel in the Personal Computer Industry.

IBM and Motorola will design a chip compatible with The IBM POWER architecture and also backwards compatible with the 68000 processor from Motorola.

The PPC will power the next generation of Macs

The Heyday of PPC

Initially everybody excited about the PPC

Even PPC architecture version of Windows..briefly.

In terms of general use personal computers PPC was used exclusively in Macintosh.

Not really picked up by any other computer manufacturers since intel cpu's cheaper.

Intel Strikes Back!Intel has tremendous resources and $$$ recognizes the performance threat the PPC represents and pours their funds into improving and enhancing x86 architecture performance.

Over a decade PPC designers are outspent by several orders of magnitude and PPC performance gains are gradually diminished.

Apple switches to Intel

2006 Apple announces that it will begin producing Macs with intel chips.

Macs will now be able to run windows. This signals the end of the PPC in the PC. Why do this? AIM partners repeatedly fail

to deliver the ppc & ppc64 cpus Apple wants in the quantities they need at the time they need them to go to market.

Also diminishing performance returns over the comparable x86 & x86_64

PPC switches to embedded systems & specialized

machines Apple switchover does not reflect a

difficiency in PPC architecture Due to high power pipelined processing

at low heat cost, PPC's are an architecture of choice in embedded systems.

For the same reasons it is also the architecture dujour for the current generation of video game consoles

TODO:

More research, more specifics about architecture, business side of PPC history.

More understanding of pipelining, other benefits of RISC architecture

Understand what Intel did to make x86 comparable...Moore's Law, faster cache...throw money at the problem

Interview SPARC researcher Robert B. Garner –this Friday.

Deliverables IEEE GHN article.... first-gen 60 GB PS3 “Fatty” that is still

running the version 3.15 Firmware and is OtherOS capable.

Running FedoraCore-12

for PPC-64. Will write some simple

assembly language Compare .o files for

simple c program?