Multiplication of (-7) and 9 by using Booth's Algorithm

M = -7 = (1001) and –M = M’ + 1 = 0111

Q = 9 = 1001

Value of SC = 4, because the number of bits in Q is 4.

$Q_n = 1$ according to the last bit of Q and $Q_{n+1}$ set as 0 at initially.

As, (-7) * 9 = -63

Value stored in AC & Q registers = 11000001

(-7) * 9 = 2’s complement of 11000001= $- (00111110 + 1)_2 = - (00111111)_2$

= - (32 + 16 + 8 + 4 + 2 + 1) = -63