Page 405 - Engineering Digital Design
P. 405

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                                                                                                                                              T/R
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                                                                                                                                                  AHH/^uh
                                                                                                                             FS-FO
                                                                                                                                   M i
                                                                                               *
                                                                                                                                              1
                                                            FIGURE 8.45
                                                                                                    «—
                                                                                                                               4y
                                                                                                          DR
                                                                                                              B
                                                                                                              A
                                                                                                                     4
                                                                                                                              — H
                                                                                            )
                                                                                          1
                                                                                                                    '
                                                                                               Done
                                                                                                              F' B
                                                                               R
                                                                                                       1-bitPALU n1
                                                                                               R
                                                                               n n-1
                                                                                                              j-t B J+i M i  M oGO
                                                                                                in
                                                                                                          Add/Sub
                                                                                                ^
                                                                                 1
                                                                                     a a a
                                                                 DONE
                                                                             n-input
                                                                                                D D 0 4
                                                                           NOR gate
                                                                                                     _...„_
                                                                                     t
                                                                                 J, A
                                                                                                          DR
                                                                                                              B
                                                                                                     C out 1
                                                                                                     ^
                                                                                                              A
                                                                                                                     4
                                                                                          ]f
                                                                                                                    '
                                                                                               Done
                                                                                                              •M
                                                                                                      1 -bit PALU.
                                                                                              R
                                                                                D 1
                                                                                                     r*
                                                                                                     •i
                                                                                                              F :  B *U^l ^ G0
                                                                                                     C in'
                                                                                              '"
                                                                                                          Add/Sub
                                                                                               ^
                                                                                                    « —

                                                                                                          DR
                                                                                                              B
                                                                                                    C out 1
                                                                                                     1
                                                      and outputs are assumed to be active high and that the rc-input NOR gate is of CMOS construction as illustrated in Fig. 8.46.
                                                                                                              A
                                                                                                                                                         B o  A o
                                                                                                                     4
                                                                                        )f
                                                                                                                     /
                                                                                                              F :
                                                                                              Done
                                                                                                                                                        B_,
                                                                                                      1-bitPALU n
                                                                               p
                                                                                               „
                                                                              0
                                                                                                               B J-1  E J^ M t M 0 GO
                                                                                                    °in'
                                                                                                          Add/Sub
                                                         Logic circuit for an «-bit PALU with completion signal capability consisting of cascaded 1-bit modules of the type shown in Fig. 8.40. Note that all inputs
                                                                                                     P 1
                                                                                                 c «° ^

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