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apple2_russian_peasant_multiplication
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Add algorithm

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michaelangel007 2020-02-05 08:48:54 -08:00
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README.MD
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@ -112,4 +112,22 @@ In Base 16:
x 2 = AC0 / 2 = 1 Yes + A = 1326
```
Algorithm:
1. Initialize Sum <- zero
2. If B is odd then add A to Sum. In C nomenclature: `Sum += A;`
3. Multiply A by 2 -- that is, Shift A **left** by one. In C nomenclature: `A <<= 1;`
4. Divide B by 2 -- that is, Shift B **right** by one. In C nomenclature: ` B >>= 1;`
5. If B is zero then STOP
6. Goto step 2
For a "BigInt" or "BigNumber" library this _isn't_ the most efficient way to
multiply numbers but it is rather trivial to implement. You only need a few
functions:
* `isEven()`
* `isZero()`
* `Shl()`
* `Shr()`
* `AddTo()`