Reverse-Engineering a Carry-Lookahead Adder in the Pentium
by hubie from SoylentNews on (#6TR08)
owl writes:
https://www.righto.com/2025/01/pentium-carry-lookahead-reverse-engineered.html
Addition is harder than you'd expect, at least for a computer. Computers use multiple types of adder circuits with different tradeoffs of size versus speed. In this article, I reverse-engineer an 8-bit adder in the Pentium's floating point unit. This adder turns out to be a carry-lookahead adder, in particular, a type known as "Kogge-Stone."1 In this article, I'll explain how a carry-lookahead adder works and I'll show how the Pentium implemented it. Warning: lots of Boolean logic ahead.
Read more of this story at SoylentNews.