3 ms·
The question would be why isn't it 4x - 1x?
by russdill 2y ago
The question would be why isn't it 4x - 1x?
- kens 2y agoThe trick is that Booth's algorithm gives you the ×8 term for free; you multiply by one more in the next base-8 digit. You can put either ×4 or -×1 into a term, but you can't put both of them into one term. So you can do ×8 - ×1 but you can't do ×4 - ×1.
- eru 2y agoI guess the decimal equivalent would be multiplying by 10 vs multiplying by 5. Or for hexadecimal: multiplying by 0x10 (16) or by 2, 4 or 8.
- mjevans 2y agoI suspect it's logically equivalent, but one bit wider in hardware. Binary 4x is left shift by 2, rather than 2x which is by one. Adding or subtracting in 2's compliment space is the same operation for the bits of the word.