Page 35 - Autumn 2024

Doubling

Fig. 21. Schematic arrangement of Halving and
Numerical Example.
Fig. 19. Schematic arrangement for Doubling. must be added into the register position below. This
can best be shown by the example:-
All that is required to double a number is to shift 50 ÷ 2 = 25.
it one place to the left, the feed back loops of the
multiplicand register are connected so that when doub- Arrangement of Machine
ling, the "1" feeds back to the "2," the "2" feeds
back to the "4," the "4" to the "8," and the "8"
to the Carry Memory buss bar. The 4, 2 and 1 lines
are connected via the half adder to the C.M., since a
combination of 4 and any other figure when doubled
will require this circuit.
We have chosen the example No. 936 as this entails
the use of the Carry Memory.

Fig. 22. Basic arrangement of Arithmetic Unit.

This shows the five stores, the three registers, the
adder, the complementer and the emitter. The emitter
can be used to insert a figure into any of the registers
which would be common to a series of cards.
It will be noticed that there are two paths, A and B
-thisenables the machine to add together the quanti-
ties held in stores 2, 3, 4 and 5 to store 1, thus enabling
Fig. 20. Example of Doubling the number 936. the calculation of the type (A + B) times C to be
carried out as it were in one run. The stores, with the
Halving exception of No. 1, can pass through the complementer.
To halve the number in the multiplier register each
Binary expressed denomination is shifted one position Shifting Registers
to the right, but as no decimal digit after halving can One of the fundamentals of valve registers is that of
exceed 9, there will be no carry up the register, and being able to transfer (or shift) the digit in one position
therefore the "ten" detector and rationalising circuits to the next position, and so on through all the stages of
are not needed. One bank of adders is necessary, how- the register. The shifting registers are composed of a
ever, because when a register position (other than the series of inter-connected triggers, one series for each
units position) holds a digit that is an odd number, a 5 register position.

18

35
Become a member: https://membermojo.co.uk/ie
Become a subscriber: https://membermojo.co.uk/subscriber
Become a sponsor: https://membermojo.co.uk/sponsor