SU951297A1 - Device for determination of two number difference - Google Patents

Description

(54) CONSTITUTION FOR DETERMINATION OF TWO DIFFERENCE

one

The invention relates to automation and computing technology and is predefined to determine the absolute value and sign of the difference of the numbers being compared.

A device for determining the difference of two numbers is known, based on sequential subtraction of single pulses from two counters in which codes of these tl numbers are stored.

However, for this device, there is a characteristic loss of speed when the AB condition is violated - where A and B are favored numbers.

The closest to the present invention is a device for determining the difference of two numbers, containing counters, which are compared comparable A and B in a parallel code, a comparison circuit, storing More and Less, elements And, a pulse generator, a sign trigger and an absolute value counter difference with the output in the form of parallel code 2.

However, the known device is characterized by the non-optimality of the circuit design, due to the fact that the algorithm used

NUMBERS

comparing numbers A and B is based on adding a definitive number to the smaller of the numbers being compared, and since it is usually not known a priori which of the numbers is smaller, two counters are required for technical realization and device, which are compared to numbers A and B.

The purpose of the invention is to expand the device.

The goal is achieved by the fact that a device containing two counters, a circuit compared, a pulse generator, a sign element trigger, the outputs of the bits of the first counter connected to the inputs of the first group of the comparison circuit, the output of the pulse generator connected to. The first input of the AND element, the output of which is connected to the counting inputs of the first and second counters, contains a register, the outputs of which bits are connected to the inputs of the second group of the comparison circuit, the first and second outputs of the comparison circuit are connected respectively to the inputs of the specified totalizer and subtraction of the first counter and with trigger trigger inputs

sign, the third output of the q BHeifflfl circuit is connected to the second input of the element I.

The drawing shows a functional diagram of the device for determining the difference of two numbers.

The device contains a reversible counter 1, a register 2, a comparison circuit 3, ikkhtsuyu .. outputs 4-6 More, Less and Unequivalence, the element And 7, generator julpup 8, the trigger sign 9 and the counter 10 absolute value of the difference, output 11 of which in etc etc devices. The numbers A and B compared are supplied in parallel code.

to inputs 12 and 13 of the reversible counter 1 and register 2, respectively, whose outputs are connected to a comparison circuit 6, outputs 4 and 5 More and Less than the comparison circuit 3 are connected to the trigger inputs of character 9 and to the inputs of setting the summation mode Ann and subtraction of counter 1, output 6 The unequality of the comparison circuit 3 is connected to the input of the element AND 7, another input of which is connected to the output of the pulse generator 8, the output of the element 7 is connected to the counting inputs of the reversible counter 1 and the counter 10 of the absolute value of the difference.

The device works as follows. . If the number A is greater than the number B, the output 4 of the comparison circuit 3 shows a signal that sets the trigger of sign 9 to the position corresponding to the plus sign, and turns the reversible counter 12 into subtraction mode. At the same time, the signal from output 6 The unequality of the comparison circuit 3 opens element 7 and the pulses from generator 8 arrive at the inputs of counters 1 and 10. When the numbers recorded in counter 1 and register 2 are compared, the output 6 of comparison circuit 3 disappears which closes the element AND 7, In this case, the counter 10 records the code of the absolute value of the difference of the supported numbers (| Cf | AB), and the state of the trigger 9 corresponds to the sign of the difference.

When the device works analogy to the case.

Using a reversible counter and register instead of two counters and one element And instead of two elements And, the outputs of which are assembly and integrated, simplify the design of this device compared to the prototype.

Claims (2)

1. USSR author's certificate number 167317, cl. G 06 F 7/02, 1963. 2. USSR author's certificate number 341031, cl. G 06 F 7/02, 1970 (prototype).