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Added explanation
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README.MD
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README.MD
@ -25,3 +25,64 @@ And enter in `123456789` * `987654321` respectively for A and B ...
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| Applesoft | 33 s |
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| Assembly | ~1 s |
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# So what the heck is it?
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An alternative algorith to implement multiplication using only:
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* bit-shift (left and right), and
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* addition.
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Example of "normal" multiplication:
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In base 10:
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```
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86
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x 57
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----
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602
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430
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====
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4902
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```
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In base 2:
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01010110 (86)
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00111001 (57)
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--------
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01010110 (86 * 2^0 = 86)
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00000000 (86 * 2^1 = 172)
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00000000 (86 * 2^2 = 344)
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01010110 (86 * 2^3 = 688)
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01010110 (86 * 2^4 = 1376)
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01010110 (86 * 2^5 = 2752)
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==============
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01001100100110 (4902 = 86*2^0 + 86*2^3 + 86*2^4 + 86*2^5)
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Example of Russian Peasant multiplication:
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In Base 10:
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```
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A B Sum
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86 57 86
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172 28 86
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344 14 86
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688 7 774
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1376 3 2150
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2752 1 4902
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```
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In Base 2:
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```
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A B Sum Sum = 0
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01010110 00111001 00000001010110 Sum += A
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010101100 00011100 00000001010110 --
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0101011000 00001110 00000001010110 --
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01010110000 00000111 00001100000110 Sum += A
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010101100000 00000011 00100001100110 Sum += A
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0101011000000 00000001 01001100100110 Sum += A
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```
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