3. Background & Motivation
• One of the most critical functions carried out
by ALU
• Digital multiplication is the most extensively
used operation (especially in signal
processing), people who design digital signal
processors sacrifice a lot of chip area in order
to make the multiply as fast as possible
• Innumerable schemes have been proposed for
realization of the operation
4. Objective
• In array multiplier we use the
signed,unsigned numbers separetly but
we want to perform the both
signed,unsigned operations at the same
time for time delay by using the
verilogHDL.
5. Introduction
The booth encoding performs the signed unsigned
modified encoding multiplier.
The requirement of the modern computer system is
dedicated and very high speed unique multiplier unit
for signed and unsigned numbers.
The carry save adder(CSA) tree and the final carry
look ahead(CLA) adder used to speed up the
multiplier operation.
6. Multiplication Schemes
• Serial Multiplication (Shift-Add)
– Computing a set of partial products, and then
summing the partial products together.
– The implementations are primitive with simple
architectures (used when there is a lack of a dedicated
hardware multiplier)
• Parallel Multiplication
– Partial products are generated simultaneously
– Parallel implementations are used for high
performance machines, where computation latency
needs to be minimized
7. EXISTING METHOD
• IN general a multiplier uses array of full adders or wallace
tree instead of the array of fas.,i.e.,this multiplier mainly
consists of the two parts: a tree to compress the partial
products such as wallace tree,and final adder.
• Because wallace tree is to add the partial products from
encoder as parllel as possible,its operation time is
proportional to, where is the number of outputs
• The most effective way to increase the speed of a multiplier is
to reduce the number of the partial products.
10. For 4*4 Array Multiplier, it needs 16
AND gates, 4 HAs, 8FAs (total 12
Adders)
For m*n Array Multiplier, it needs
m*n AND gates, n HAs, (m-2)*n FAs,
(total (m-1)*n Adders)
11. Advantages & Disadvantages
• Advantages:
– Minimum complexity
– Easily scalable
– Easily pipelined
– Regular shape, easy to
place & route
• Disadvantages:
– High power consumption
– More digital gates
resulting in large chip area
12. PROPOSED METHOD
• TO reduce the number of calculation steps for partial
products,MBE algorithm has been applied mostly where
wallace tree has taken the role of increasing the speed to add
the partial products.
• To increase the speed of the MBE algorithm many parallel
multiplications have been detected but a configurable booth
multiplier has been designed which provides a flexible
arithmatic capacity an d a tradeoff between output precision
and power consumption.
13. Booth's Algorithm Advantages
• Multiplication can be sped up
• When large number of consecutive 1s in
multiplier
• Replace consecutive additions
• Subtract at least-significant end
• Add at position to the left of the most-
significant end
15. Conclusions
• Array multiplier is implemented and verified in
Verilog
• Although it utilizes more gates, the
performance can easily be increased using
pipeline technique
• As a parallel multiplication method, array
multiplier outperforms serial multiplication
schemes in terms of speed.
