Computer indexing apparatus

Claim 1

IN APPARATUS FOR MODIFYING BY LEVELS, INPUT SIGNALS REPRESENTATIVE OF ADDRESSES BY INPUT SIGNALS REPRESENTATIVE OF ALTERATION QUANTITIES AS SPECIFIED BY CONTROL REPRESENTATIVE INPUT SIGNALS: REGISTER MEANS INCLUDING FIRST, SECOND AND THIRD GROUPS OF SETTABLE STAGES OPERABLE TO ASSUME STATES REPRESENTATIVE OF INPUT SIGNAL; INPUT MEANS FOR CAUSING SAID FIRST GROUP OF STAGES TO ASSUME STATES CORRESPONDING TO SAID ADDRESS INPUT SIGNAL, SAID SECOND GROUP OF STAGES TO ASSUME STATES CORRESPONDING TO SAID ALTERATION INPUT SIGNALS FOR A NUMBER OF LEVELS AND SAID THIRD GROUP OF STAGES TO ASSUME STATES CORRESPONDING TO SAID CONTROL INPUT SIGNALS FOR A NUMBER OF LEVELS; ADDER MEANS FOR PRODUCING OUTPUT SIGNALS REPRESENTATIVE OF THE SUM OF A FIRST GROUP OF ADDER SIGNALS AND A SECOND GROUP OF ADDER SIGNALS; CONTROL MEANS FOR PRODUCING ROUTING SIGNALS FROM SELECTED ONES OF SAID THIRD GROUP OF REGISTER STAGES FOR A SELECTED LEVEL; FIRST ROUTING MEANS, UNDER CONTROL OF SAID ROUTING SIGNALS, FOR REPEATEDLY TRANSFERRING TO SAID ADDER MEANS FIRST AND SECOND GROUPS OF ADDER SIGNALS REPRESENTATIVE OF THE STATES OF SAID FIRST GROUP OF REGISTER STAGES, AND SAID SECOND GROUP OF REGISTER STAGES FOR SAID SELECTED LEVEL; AND SECOND ROUTING MEANS, UNDER CONTROL OF SAID ROUTING SIGNALS, OPERABLE TO MAKE SAID ADDER SUM OUTPUT SIGNALS AVAILABLE TO SAID REGISTER INPUT MEANS FOR ENTRY INTO SAID FIRST GROUP OF STAGES.