i read somewhere that computers add using some combination of logic gates, and that the only way multiplication could be done is through addition. is this true, and if so, how?

ty in advance :p

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- 01-17-2002ygfpersonaddition
i read somewhere that computers add using some combination of logic gates, and that the only way multiplication could be done is through addition. is this true, and if so, how?

ty in advance :p - 01-17-2002starX
think of multiplication like this:

9 multiplied by 8 means 9 eight times over,

so 9 * 8 == 9+9+9+9+9+9+9+9.

starX

www.axisoftime.com - 01-18-2002Deckard
I believe you're thinking of

**boolean logic gates**. You may be interested in the explination provided here. - 01-18-2002ygfperson
about multiplication: what if the number were big? back when i had a tandy 1000ex(8.077 mhz, 1984 i think) basic could do a for i=1 to 5000, next loop in one second. is there some sort of help the processor gets?

- 01-18-2002Salem
Well the most common? technique is software is using shift-and-add

http://www.google.com/search?hl=en&q=shift+add+multiply

There is also this

http://www.google.com/search?hl=en&q=booths+algorithm

And perhaps this

http://www.chipcenter.com/circuitcel.../c1200db11.htm - 01-18-2002iain
the multiplication cannot actually be done by a computer due to the logic systems it uses, so the multipolication is carried out by bit-shifting and addition

- 01-18-2002QuestionC
Well, multiplication and loops are different beasts.

For multiplication: Technically, you could just have a multiplication table in your CPU, but the way I learned it, it's a combination of shifts, additions, and perhaps subtractions.

For loops: You can think of increment or decrement operators as even more basic than addition and subtraction. Loops are very important, so much that loop commands are commonly a part of a processor's architecture. - 01-18-2002sean
or you may be interested in wasting your time clicking the link provided here

- 01-19-2002DeckardQuote:

*Originally posted by Sean*

**or you may be interested in wasting your time clicking the link provided here**

*That*is a stroke of pure genius which should be prominently displayed at the beginning of the FAQ. :)