Patent GB-826612-A (GB)
Title: Improvements in or relating to electronic digital computers
Inventor: GILLIES DONALD BRUCE
IPC: G06F9/30
Filed: 1955-01-24
Abstract: 826,612. Electronic calculating apparatus. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Dec. 2, 1955 [Jan. 24, 1955], No. 34636/55. Divided out of 826,613. Class 106. In an electronic digital computer in which a storage address defining portion of an order word signal may be modified, prior to its being effective in the machine control system, by combining it with a separate modifier word, the address defining portion of the order word may be combined with the complete modifier word or various portions thereof in different ways determined by another part of the order word. The invention is described as applied to the machine disclosed in Specification 826,613, in which a 42-digit order word, Fig. 2 (c), is divided into order portions A, B, each of which is divided in time order into M, F, X, N digits. The three M digits define the address in the accumulator register group 2, Fig. 1, of the high-speed store 10, of any required modifier word to be used for altering the subsequent N or X digits only, or both the N and X digits of the same order. The six F digits define the function to be performed by the machine. The three X digits select the particular accumulator register in group 2 that is to be connected to the mill 5, and the seven N digits define the address in the store 10 where one operand is to be obtained or delivered. Operation.-As described in Specification 826,613, a new order word is selected from one of thirty-two speed registers 4, Fig. 1, only two of which 64 and 95 are shown in Fig. 6. The selected word, which circulates in the 42 digit delay line Y78 of the selected register, is released at the start of the D beat of the C period of the machine rhythm through a gate Y96 ... Y332 over a bus Y40 and a " doubleentry unit delay " A41, Fig. 4, to the input 67 of an adder ADR1. The order word flows down the control line A24 ... A48 to produce corresponding outputs at 10, I1 ... I17. The outputs I1, I2 set up M digit staticisors, Fig. 5 (not shown), at digit time 26 of the C period D beat which select the modifier word address from the seven accumulator registers ACR 1... ACR7, Fig. 6. The modifier word signal then flows via the " double entry unit delay " S58, S54, S52 ... P91 of the selected register, one of two further " double entry unit delays " V58, V59 and through further unit delays V69, V79 to bus Y47. Only the signals in digit intervals 25 ... 38, Fig. 2 (a), 2 (d), appear on the bus and are 4-digit intervals late on standard time. These signals may pass direct to the upper entry of a double-entry unit delay A51, or by way of three further unit delays A105, A106, A107 to the lower entry thereof, the choice of entry path being determined by the F (function) digits of the order word, which, through F digit staticisors, Fig. 5 (not shown), and further staticisors shown in Fig. 4 determine the " on " times of the waveforms X22, X23 controlling the two entry gates. The order word function digits f0, f1, f2, determine the units (decimal) digit value, and the function digits f3, f4, f5, the tens digit value of the order code number. The complete order code is given in the Specification. For any order code number 00-07, 10-17, 20-27, 30-37, the modifier digits 11, 12, 13 only are operative, Fig. 2 (e) and modify, by being added in ADR1 to the previously existing N digtis n2, n1, n0 of the A order. For any order code 40-47, 50-57, 60-67 the modifier digits 13, 12 . . . 4, Fig. 2 (h) are operative and modify all six N digits of the A order and add a further three digits n7, n8, n9 for further control purposes. For order code numbers 70-75 all the modifier digits 13 . . . 1, Fig. 2 (g) are operative, and modify the previously existing X digits as well as all the N digits. For order code numbers 72 ... 77 the modifier digits 10, 9 ... 1, Fig. 2 (f) are operative, and modify all the N digits n0-n6 and add further N digits n7, n8, n9. The output of the adding circuit which is the selected order word containing both A, B orders in which the A order has been modified then flows down the control line A24 . . . A48 to control the subsequent machine operations as described in Specification 826,613. The unused digits of a normal length (modifier) word may be used, for other purposes, for example, to accommodate a group of counting-digits for effecting a predetermined number of repetitions of an order or programme sequence. Specifications 789,207, 789,208, 789,209, 796,404 and 826,614 also are referred to.