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Topic: MULTIPLY WITHOUT MULTIPLYING (Read 3100 times) |
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eviljed
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MULTIPLY WITHOUT MULTIPLYING
« on: Aug 9th, 2002, 10:50am » |
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Multiply by 8 without using multiplication or addition. Now do the same with 7.
For 8: Convert to binary. Shift left twice. That'll do it. (note that the shifts put zeros in the least significat values).
For 7: I'll have to get back to you on that.
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eviljed
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Re: MULTIPLY WITHOUT MULTIPLYING
« Reply #1 on: Aug 9th, 2002, 11:02am » |
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I just had an ID-10T error. (aka, i'm an idiot). You shift to the left three times. Two shifts only multiplies it by 4.
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Aaron
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Re: MULTIPLY WITHOUT MULTIPLYING
« Reply #2 on: Aug 9th, 2002, 11:54am » |
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I am assuming that addition and subtraction are different functions here...
n = (n << 3) - n;
I am still fiddling with the bits for a solution that involves no arithmatics, short of going all the way to implementing a binary subtraction function with logigates. 
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-D-
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Re: MULTIPLY WITHOUT MULTIPLYING
« Reply #3 on: Aug 9th, 2002, 4:27pm » |
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There is a long thread on this already furthur down the page with several ideas on it.
-D-
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