CprE 583 – Reconfigurable Computing Multiplication Shift and add operations Need N bit adder, M cycles 42 = 101010 Multiplicand (N bits) x 10 = x 1010 Multiplier (M bits) 000000 101010 Partial products + 101010 420 = 111001110 Product (N+M bits) CprE 583 – Reconfigurable Computing September 5, 2006

CprE 583 – Reconfigurable Computing X3 X2 X1 X0 Array Multiplier Y0 Area – N x M cells Delay – O(N+M) Y1 X3 X2 X1 X0 + + + + Y2 X3 X2 X1 X0 + + + + Y3 X3 X2 X1 X0 + + + + Z2 Z1 Z0 September 5, 2006 CprE 583 – Reconfigurable Computing

CprE 583 – Reconfigurable Computing X3 X2 X1 X0 Carry-Save Y0 Y1 X3 X2 X1 X0 + + + + Y2 + + + + There's one critical path here - along the right-hand side and across the bottom. Y3 + + + + Z2 Z1 Z0 CprE 583 – Reconfigurable Computing September 5, 2006