
Quotient-Digit Selection Function
305
EXAHPLR 5.3
2. By using the eight bits of the four most-significant positions of the
carry-save representation of 2w[j] as inputs to the combinational
network, as shown in Figure 5.30(b).
Since this combinational network is relatively simple, we use this second
scheme to obtain a faster implementation. A possible implementation in which
the digit qj+l is represented in sign-and-magnitude by
(qs,
qm)
is as follows:
qm : (P-IPOPl) r
5.110
qs
= P-2 G (g-1 +
P-lgo at- P-lPogl)
where
Pi
-- ci ~ .-r i
gi
"- Ci " S i
and (c-2, c-1, co, c 1), (s -2, s -1, s o, s 1) are the carry and sum components ...