The 6502 overflow circuit, analyzed at a physical level

[BLuRry <brendan.robert@gmail.com>]

This is a pretty interesting read!

Here's a quote from Ken Shirriff's blog post:

In this article, I show how overflow is computed in the 6502 microprocessor at the transistor and silicon level. I've discussed the mathematics of the 6502 overflow flag earlier and thought it would be interesting to look at the actual chip-level implementation. Even though the overflow flag is a slightly obscure feature, its circuit is simple enough that it can be explained at the silicon level.

The full article can be found here: http://www.arcfn.com/2013/01/a-small-part-of-6502-chip-explained.html

-Brendan