
Combinational Multiplication with Recoding
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4~
the first approach. Consequently, we concentrate on the radix-4 case, in which
the recoding is done anyhow to eliminate the multiple 3x.
The sequential radix-4 recoding for sign-and-magnitude presented before
has to be modified for the two's complement case. One possible modification is
to extend the sign: one bit ifn is odd and a whole radix-4 digit if it is even. Then,
as in two's complement addition, the carry-out of the extended digit vector is
discarded. However, this increases the number of cycles when n is even.
Two variations are possible to eliminate the need for the additional ...