Booth's Algorithm

Question

Please tell the procedure of muntiplication of (-5)x (-3) using booth algorithm?

Answer 1

$m = -5 = 1011$

$-m = 5 = 0101$

$r \ = -3 = 1101$

 let x and y represent the number of bits in m and r.

$A = 1011 \ 0000 \ 0$

$S = 0101 \ 0000 \ 0$

$P = 0000 \ 1101 \ 0$

Least significant 2 bits of P are  $10$

1) if $10$ then $P + S$, $0101 \ 1101 \ 0$ and shift 1 bit to the right, So P = $0010 \ 1110 \ 1$

2) if $01$ then $P + A$, $1101 \ 1110 \ 1$ and shift 1 bit to the right, So P = $1110 \ 1111 \ 0$

3) if $10$ then $P + S$, $0011 \ 1111 \ 0$ and shift 1 bit to the right, So P = $0001 \ 1111 \ 1$

4) if $11$ then do nothing and shift 1 bit to the right, So P = $ 0000 \ 1111 \ 1$

After dropping the LSB, we're left with $0000 \ 1111$ which is $15$

Comments

Nicely explained @Mk Utkarsh

We have perform shift action when $10, 01, 11, 00$ occurs. Ryt.

---

Shubhanshu yes in each iteration

---

Thanks.