Linked by Thom Holwerda on Tue 29th Jan 2013 02:17 UTC
Hardware, Embedded Systems "The arithmetic-logic unit is a fundamental part of any computer, performing addition, subtraction, and logic operations, but how it works is a mystery to many people. I've reverse-engineered the ALU circuit from the 8085 microprocessor and explain how it works. The 8085's ALU is a surprisingly complex circuit that at first looks like a mysterious jumble of gates, but it can be understood if you don't mind diving into some Boolean logic."
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RE[3]: Ok
by ameasures on Wed 30th Jan 2013 18:49 UTC in reply to "RE[2]: Ok"
ameasures
Member since:
2006-01-09

Am I the only one that misses the old days when we had so many choices in both CPUs and even in X86? ...


Yep I miss'em too. Not enough to want to go back there though. I remember tiptoeing around flaws in specific chips with particular operating systems.

Heck - even 287 chips that would throw a wobbly given a very specific combination of valid (FP) arithmetic inputs. It was reproduceable very consistently. Took a few engineers a while to spot that it was the chip, not the high level code and not the compiler!

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