A method
of generating an effective address that modifies the specified address given in
the instruction by the contents of a specified index register. The modification
is usually that of addition of the contents of the index register to the
specified address. The automatic modification of index-register
contents results in an orderly progression of effective addresses being
generated on successive executions of the instruction containing the reference
to the index register. This progression is terminated when the index register
reaches a value that has been specified in an index-register handling
instruction.