Since the best-case reduction per level is p/2, for l levels we get
pl
ml ~ 2t_1
and
3.30
l ,~ logp/2(ml/2)
3.31
Selecting the Value p
A larger p results in a smaller number of adder levels, in both the linear array and
in the tree. However, the delay and complexity of the adder increase. Moreover,
the connections between levels are more regular for values of p that are powers
of two, as illustrated in Figure 3.15. Consequently, the best value of p depends
on the requirements for the multioperand adder.
As an example, we compare the use of trees of [3:2] and [4:2] adders for
a multioperand ...
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