The 6502 Rotate Right Myth

[BigDumbDinosaur]

barnacle wrote:

BigDumbDinosaur wrote:

Why does it keep coming up?

Surely: why does it keep coming around?

Neil (I'll get my coat...)

[Chromatix]

Quote:

Bil Herd summarizes the situation. “No chip worked the first time,” he states emphatically. “No chip. It took seven or nine revs [revisions], or if someone was real good they would get it in five or six.”

The ARM1 must be the exception that proves the rule. It did work first time - the consternation at bring-up was over a fault in the evaluation board, not the chip!

Granted, some changes were made before full commercial production began, resulting in the ARM2. These would have been in light of experience in actually running the hardware, and discovering that a multiply instruction would actually be pretty useful. That doesn't detract from the ARM1 working as designed, fresh out of the oven.

[kakemoms]

Chromatix wrote:

The ARM1 must be the exception that proves the rule. It did work first time - the consternation at bring-up was over a fault in the evaluation board, not the chip!

Granted, some changes were made before full commercial production began, resulting in the ARM2. These would have been in light of experience in actually running the hardware, and discovering that a multiply instruction would actually be pretty useful. That doesn't detract from the ARM1 working as designed, fresh out of the oven.

Oh, an ARM guy.

I always wanted to ask: why did you wire out A0 and A1?

[Chromatix]

Not sure. I was something like 5 or 6 at the time, so…