this post was submitted on 25 Feb 2024
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Science Memes

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Biology OP (mander.xyz)
submitted 8 months ago* (last edited 8 months ago) by [email protected] to c/[email protected]
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[–] [email protected] 2 points 8 months ago (4 children)

But....how?

[–] [email protected] 4 points 8 months ago* (last edited 8 months ago) (1 children)

The other replies are simplifying too much. Just adding or subtracting in a loop would be far too slow.

A multiplier will find the partial products by using AND gates, and then sum them, which is very similar to long multiplication as they teach you in school. This article explains it pretty well.

Division is more complicated. It's sort of done like long division, but apparently that is slow and there's some magic with two's complements that can make it faster. Honestly I don't fully understand it yet.

[–] [email protected] 2 points 8 months ago

That article was really good. I feel like if someone explained it to me at a pub or party I could somewhat talk about it without sounding like a total ludite.

[–] [email protected] 4 points 8 months ago

Once you go down to logic gates. A XOR gate for example makes 1+1 = 0

[–] [email protected] 2 points 8 months ago* (last edited 8 months ago)

It recursively subtracts until the number goes at or below zero. The iterations is the output and the reminder is how much it went below zero.

[–] [email protected] 2 points 8 months ago (1 children)

Subtract divisor from dividend until you hit zero. Number of subtractions is the quotient. Don't ask about non-whole numbers.

[–] [email protected] 2 points 8 months ago

The remainder is the amount of overflow when you go below zero.