# Booth bit-pair recoding technique

In Booth's bit-pair recording technique how to multiply a multiplicand with -2 or 2? For example while multiplying 01101(+13, multiplicand) and 11010(-6, multiplier), we get 01101 x 0-1-2.

How to multiply the multiplicand using -2?

• I thought the result is 1110110010, I do not fully understand your notation, shouldn't you recode the multiplier to 0-11-10? – Evil Aug 26 '16 at 0:34

## 3 Answers

In bit recoding multiplication, e.g. 01101 times 0, -1, or -2.

• For multiplying with -1: Take 2's complement of 01101 i.e: 10011
• For multiplying with -2: Add 2's complement of 01101 i.e: 10011 + 10011= 100110
• Take a look at the rendered answer before finalizing your post. – Yuval Filmus Mar 7 '17 at 7:02

multiplying with -2 : Take 2's complement and Shift Left one bit

First you must come to thr lsb of bit pair recoding i.e say 0 -1 2. So here lsb is 2 it means we must multiply 10 with multiplicand because based in the recoding table if it is positive 2 then we multiply and same procedure must be followed for next bit i.e -1 and so on

• I have troubling following what you're saying. Can you please clean up the language and maybe check the chain of reasoning? – Raphael Nov 13 '16 at 9:42