JPH01277958A - Electronic desk calculator - Google Patents

Abstract

PURPOSE:To perform display and fraction calculation including a real number by providing a decimal point position circuit where the decimal point position is stored by the indication from an arithmetic control circuit. CONSTITUTION:The signal from a keyboard 11 is converted to data, where number and fraction information is encoded to a binary code, by a key discriminating circuit 12 and this data is sent to a display data register 13 by the write signal from an arithmetic control circuit 16. A decimal point signal is converted to binary coded data indicating the decimal point by the key discriminating circuit 12, and the decimal point position is stored in a decimal point position circuit 14 by the count signal from the arithmetic control circuit 16. Binary coded data is successively stored in the display data register 13 in accordance with key information. A display control circuit 15 receives signals of the register 13 and the circuit 14 to display a fraction accompanied with the decimal point. The circuit 16 receives signals of the register 13 and the circuit 14 to perform arithmetic in accordance with determined procedures.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic desktop calculator, and more particularly to an electronic desktop calculator that allows input in the form of fractions.

[Conventional technology]

Conventionally, in this type of electronic desktop calculator, the only numerical values that can be input as fractions are integers, and if a decimal is included in the fraction and is input, an error will be displayed.

[Problem to be solved by the invention]

The conventional electronic desk calculator mentioned above has the function of adding, subtracting, multiplying and dividing numbers including a decimal point.
When trying to input ÷C) directly into a calculator as the numerical value shown by formula AB4), the number A is used because fractions only accept integers.

Since B and C are real numbers with numbers below the decimal point, there is a drawback that they must be input in the form of IL.

[Means to solve the problem]

The electronic desktop calculator of the present invention is an electronic Tojo calculator equipped with keys for numbers, a decimal point, and a fraction, and an arithmetic control circuit for inputting and calculating fractions. a key discrimination circuit that generates a numeric code, a decimal point code, and a fractional code; a display data register that receives and stores the numeric code and fractional code from the key discrimination means; and a display data register that receives the numeric code, decimal point code, and fractional instruction code. It is constituted by having a decimal point position circuit that stores the decimal point position according to instructions from the arithmetic control circuit, and a display control circuit that displays a fraction with a decimal point based on the storage contents of the display data register and the decimal point position circuit. .

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In the figure, 11 is a keyboard, which includes numbers, decimal point, fraction indication keys, etc. for inputting numerical values. Reference numeral 12 denotes a key discrimination circuit which discriminates the operated key and generates a 4-bit binary encoded signal corresponding to the key. Reference numeral 13 denotes a display data register for storing binary coded information such as numerical values 1 and fraction indication symbols. 1
A decimal point position circuit 4 stores the digit position in which the decimal point is located in the display data register 13. Reference numeral 15 denotes a display control circuit that uses signals from the display data register 13 and the decimal point position circuit 14 to display the contents in a form that is understandable to the operator. 16 is an arithmetic control circuit that performs arithmetic processing according to stored procedures.

FIG. 2 is a procedure diagram showing an example of human input from the keyboard 11 of FIG. 1, and this example shows steps in key operation to input 12-1-. Steps 1, 3, and 5.7 correspond to numeric key operations, and step 2.6 corresponds to fractional key operations, and the key information is sent to the display data register via the key discrimination circuit 12 in the same way as the numeric information. 3 in the form of a binary code. Step 4 corresponds to the decimal point key operation, and the decimal point position circuit 14 stores the digit position input to the display data register 3 before this key operation. In the example shown in FIG. 2, the decimal point key is operated only once, but if there are multiple decimal point key operations, a plurality of decimal point positions will be stored.

FIG. 3 is a block diagram of the display data register 3 and decimal point position circuit 14 shown in FIG. A write signal from the circuit 16 is sent to the display data register 13. The decimal point signal is converted into binary coded data representing the decimal point by the key discrimination circuit 12, and is sent to the digit position register 14b via the digit position counter 14a in response to a count signal from the arithmetic control circuit 16. In the example shown in FIG. 2, the decimal point is located at the third digit from the right of the digit position register 14b.

Note that the display data register 13 has 4 bits corresponding to the key information.
Bit binary coded data is stored sequentially from the right.

Therefore, the display control circuit 15 receives the signals from the display register 13 and the decimal point position circuit 14 and displays a fraction with a decimal point attached thereto. The arithmetic control circuit 16 also receives signals from the display data register 13 and the decimal point position circuit 14, and performs arithmetic operations according to a predetermined procedure.

〔Effect of the invention〕

As described above, the present invention has the effect that even if the input numbers are real numbers, by providing a decimal point position circuit, display and fraction calculation including real numbers, which was previously impossible, can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 3 is a procedure diagram showing an example of the key operations shown in the figure, and FIG. 3 is a configuration diagram of the display data register and decimal point position circuit of FIG. 1. 11... Keyboard, 12... Key discrimination circuit, 13
... Display data register, 14... Decimal point position circuit, 14a... Decimal point position counter, 14b... Decimal point position register, 15... Display control circuit, 16.
...Arithmetic control circuit.

Claims (1)

[Claims] In an electronic desk calculator equipped with keys for numbers, decimal point, and fractions, and equipped with an arithmetic control circuit that inputs and calculates fractions, numerical codes, decimal points, and fraction codes can be read by operating the numbers, decimal point, and fractions keys, respectively. A display data register that receives and stores the numerical code and fractional code from the key determining means, and a decimal point according to instructions from the arithmetic control circuit that receives the numerical code, decimal point code, and fraction instruction code. An electronic desktop calculator comprising: a decimal point position circuit that stores a position; and a display control circuit that displays a fraction with a decimal point based on the contents stored in the display data register and the decimal point position circuit.