pineappledesign:

6502 is an 8-bit CPU of the MOS Technology. The 6502 was less famous than 8080/Z80 and 6800/6809 in Japan, however, it was still widely used as a CPU of Nintendo’s Famicom (Nintendo Entertainment System).

The 6502 was designed as a cheeper version of 6800, and chosen as the core of Apple II by Steve Wozniak. The 6800 was said to be based on design of PDP-11, and had very clean (simple, orthogonal, and complete) instruction set. The 6502 had a reduced version of the instruction set of 6800. (Apple later began using 68000, a 16/32-bit version of 6800 family for its Macintosh computer.)

The spirit of 6502 —- clean instruction set on economical processor —- was inherited to Acorn’s RISC Machine, that is currently known as ARM. The Acorn was a huge 6502 user and also a developer of extender (co-processor) of the 6502; they should have known the 6502 quite deeply.

In 1990 the ARM department was spin off from Acorn and succeeded to be funded by Apple Computer. The first licensed ARM processor (ARM 610) was used as a core of Apple’s Newton.

As you know, the Newton families had been faded away from Apple’s line-up ages ago, however, the ARMs have been supporting Apple’s products for many many years by powering iPod, iPhone, iPad, and Apple TV.

I think Woz have had the right choice.

かつて6502という8ビットCPUがあった．日本では8080/Z80や6800/6809ほど有名ではないが，ファミコンのCPUと言えばどれだけ普及したかお分かりいただけよう．

この6502は安価な6800として設計された要素が色濃く，そのようなCPUを求めていたウォズによって Apple II のCPUに選ばれた．もともと6800はPDP-11の影響を強く受けたと言われており，クリーンな（簡潔で，直交していて，かつ十分な）命令セットを持っていたのだが，6502はその縮約版を備えたことになる．（アップルは後に6800を拡張した68000をMacに採用する．）

クリーンな命令セットを安価なプロセッサに載せるという6502の精神は，6502ユーザであり，6502の拡張プロセッサまで作っていた英国のAcornに引き継がれる．このようにして出来たのが Acorn RISC Machine すなわちARMだ．

1990年にAcornのARM部門はスピンオフし，アップルからの出資と共同研究を受ける．その結果ライセンスされたARM610はNewtonのプロセッサとして利用される．

もちろんNewtonがアップルのカタログから消え去ってから無限の時間が経過したが，いつの間にか，ARMプロセッサはアップル製品の屋台骨を支えている．つまり，iPod, iPhone, iPad, Apple TV なんかはみんなARMプロセッサだ．

ウォズの直感は正しかったのだね．