JPH0117174B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an index data display method in a small electronic calculator.

In a conventional small electronic calculator, that is, a functional calculator, which is equipped with a functional calculation function, the input range thereof is |x|<1×10 ¹⁰⁰ , where x is the exponent, and the range in which numerical values are held is also the same. Therefore |x|1
When it reaches ×10 ¹⁰⁰ , an error is displayed as an overflow, and when it reaches |x|1×10 ^-100 , it is displayed as an underflow and 0 is displayed. In this case, overflow and underflow checks are performed after each calculation.

However, in conventional functional calculators using the above calculation method, although the final result can be displayed, overflow or underflow may occur during the calculation, and the answer may not be obtained. For example, in the expression r=√ ² + ² , if |x|×10 ⁵⁰ or |y|1×10 ⁵⁰ , an overflow occurs in the operation of x ² or y ² and is treated as an error.

Also, in the formula tan hx=e ^x −e ^-x /e ^x +e ^-x , when |x|230, e ^x overflows,
I can't find an answer. In this case the actual answer is tan hx
= ±1.

Furthermore, when a calculation formula is programmed and executed in a computer other than a functional calculator, such as a program calculator, overflow or underflow occurs during the calculation, and correct values are often not obtained. In addition, when creating a program, there was a problem in that calculation formulas had to be transformed in consideration of the above.

The present invention has been made in view of the above points, and by fluidly configuring the exponent part and the mantissa part, the range of numerical values that can be displayed can be expanded, and calculations that could not be performed in the past can be made possible. The purpose is to provide a method for displaying index data that is possible.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a key input section, and data input from this key input section 1 is sent to a control section 2. This control unit 2 is composed of, for example, a ROM (read-only memory) and stores various microprograms, and outputs data corresponding to key operations from output line a, addresses from output lines b and c, and output line d from output line d. Output various instructions. Data and addresses output from output lines a and b of the control section 2 are sent to the selector 3. This selector 3 selects an input/output line according to the address from the control section 2, and transfers the selected data to the calculation memory 4. The calculation memory 4 is composed of various calculation registers such as an X register 4a, a Y register 4b, and a Z register 4c. The register 4a,
4b...etc., for example, has a 15-digit structure as shown in Figure 2, with the 0th to 3rd digit being the exponent part and the 4th to 4th digit being the exponent part.
The 14th digit is the mantissa. Furthermore, the exponent part stores exponent data in the 0th to 3rd digits, and the 3rd bit of the 3rd digit is a sign indicating the sign indicating the sign of the exponent digit, and the 4th
The bit stores a sign indicating the significand of the significand. Thus, the data written in each register 4a, 4b, . . . in the memory 4 is sent to the selector 5. This selector 5 selects an input/output line according to the address given from the control unit 2 via the output line c, and outputs the selected data to the arithmetic circuit 6, exponent digit detection unit 7, and exponent digit number determination unit 8. do. The finger digit number detection section 7 detects the position of the exponent digit according to instructions given from the output line d of the control section 2, and transmits the detection signal to the control section 2, the arithmetic circuit 6 and the exponent digit number discriminating section. Give to 8. The exponent digit number determination unit 8 determines the exponent digit number and provides the determination result to the display control unit 9. on the other hand,
The arithmetic circuit 6 performs arithmetic operations on the data input from the selector 5, and outputs the result of the arithmetic operation to the memory 4 via the selector 3 and to the display control section 9. Further, the arithmetic circuit 6 includes a discriminating section for discriminating the presence or absence of data, the presence or absence of a carry signal, etc. in the arithmetic result, and sends the discrimination result J to the control section 2. In addition, the display control section 9
controls the number of digits of the exponent part and the mantissa part according to the determination result of the exponent digit number determination part 8, and displays the data on the display part 10. The display unit 10 has a display digit number of, for example, 10 digits, and in the case of exponent display, the lower three digits display the exponent, and the upper six or seven digits display the mantissa.

Next, the operation of the above embodiment will be explained. In the present invention, the data storage format is |x|<1×10 ¹⁰⁰⁰ , and when the exponent part is in the range of -99 to 99, n digits for the mantissa and 2 digits for the exponent are displayed. And if the exponent part is 3 digits,
That is, in the range of -999 to -100 and 100 to 999, the mantissa is n-1 digits and the exponent part is 3 digits. For details, refer to the flowchart in Figure 3 below.√(123×10 ⁴⁹ ) ² +(456×
10 ⁴⁹ ) The case of performing the operation ² will be explained. FIG. 4 shows the key operations, the storage state of the register, and the display state of the display unit 10 when performing the above calculation. First, when "123", "EXP", and "49" are entered from the key input section 1 as shown in FIG. 1, "123" is placed in the mantissa part of the 49" is set. and,
The data held in the X register 4a is sent to the display control section 9 via the arithmetic circuit 6, and "123.49" is displayed on the display section 9. Next 2
When the "x ² " key is operated as shown in FIG. 4 to perform a multiplication operation, the operation flow shown in FIG. 3 is started. First, in step _S1 , the mantissa,
Exponential processing is performed, and the position of the first digit of the mantissa data "123" held in the Become. In this case, the data is shifted so that the decimal point is at the 13th digit of the X register 4a. Next, the process advances to step _S2 , where the data held in the X register 4a is read out to the arithmetic circuit 6, and the arithmetic operation of ^x2 is performed, that is, "(1.23×10 ⁵¹ ) ² ".
is calculated, and the calculation result is ``1.5129×
10 <sup>102</sup> '' is again written to the X register 4a as shown in FIG. Then, in step <sub>S3</sub> ,
It is determined whether the exponent data in the X register 4a is less than or equal to 3 digits or greater than 3 digits, and if it is greater than 3 digits, it is treated as an error. If the exponent data is 3 digits or less, the process proceeds to step <sub>S4</sub> , where the exponent digit number determining unit 8 determines how many digits the exponent data has. In this step <sub>S4</sub> , the index data is 3.
If it is determined that it is a digit, proceed to step <sub>S5</sub> . If it is determined that it is two digits, proceed to step <sub>S6</sub> . If it is determined that it is one digit, proceed to step <sub>S7</sub> . In step <sub>S5</sub> above, the mantissa data of the 4th to <sub>13th</sub> digits of the X register 4a, that is, the mantissa data of
The 3-digit exponent data of the digits X <sub>0 to 2</sub> is sent to the display control unit 9, and the data of X <sub>4 to 13</sub> is lowered until the data of the lowest digit matches the 5th digit of the display unit 10. It is displayed in the 10th to 5th digits of the display unit 10, that is, the upper six digits. In this case, if the number of digits of the data is greater than the number of display digits, that is, six digits, the data is down-digited until the most significant digit of the data matches the most significant digit of the display section 10, and the lower overflow is discarded. Further, the index data is displayed as is in the lower three digits of the display section 10. In addition, in step <sub>S6</sub> , the mantissa data of X4 <sub>to X13</sub> in the X register 4a and
Send the two-digit index data of X <sub>0 to 1</sub> to the display control section 9,
X Presence or absence of <sub>4 to 13</sub> The data of the lowest digit is 4 on the display section 10
The digit is lowered until it matches the digit, and the display unit 10 displays the digits from the 10th digit to the 4th digit, that is, the upper 7 digits. In this case, if the number of digits of the data is greater than the number of displayed digits, data shift processing and overflow data truncation processing similar to step <sub>S5</sub> above are performed. Furthermore, if it is determined in step <sub>S4</sub> that the exponent data is one digit and the process proceeds to step <sub>S7</sub> , the data can be displayed without displaying the exponent, so the decimal point of the mantissa data is processed according to the exponent. After the X register 4a is adjusted, as shown in step <sub>S7</sub> .
Send the data of X <sub>4 to 13</sub> to the display control section 9. and,
After the display control unit 9 performs data down-down processing, all digits of the display unit 10 are used to display the data. Therefore, when performing the above calculation of x <sup>2</sup> ,
Since the index data is "102", which is 3 digits, proceed from step <sub>S4</sub> to step <sub>S5</sub> , and display section 1.
0, "1.5129 102" as shown in Figure 4 2
will be displayed. Subsequently, as shown in FIG. 4, when the "+" key is operated, the contents of the X register 4a are transferred to the Y register 4b via the selector 5, arithmetic circuit 6, and selector 3. And the fourth
As shown in Figure 4, the following calculation data "456""EXP"
When "49" is input, this calculation data is written into the X register 4a and displayed on the display section 10 as "456.49". Next, when the "x <sup>2</sup> " key is operated as shown in FIG. 4, the same processing as described above is performed according to the calculation flow shown in FIG. That is, in step <sub>S1</sub> , the decimal point is moved to the highest digit by mantissa and exponent processing, and becomes ``4.56×
10 ⁵¹ ”, and the square calculation is performed in step S ₃ to obtain the calculation result of “2.07936×10 ¹⁰³ ”. Since the index data in this case is three digits, the process proceeds from step _S4 to step _S5 , where the same display processing as in the case of FIG. . and,
Finally, _when the ``√'' key is operated, the Y register 4b is
The content "1.5129×10 ¹⁰² " and the content "2.079360×10 ¹⁰³ " of the X register 4a are added, and
The square root of the addition result is “4.722975757×
10 ⁵¹ '' is determined and written to the X register 4a. Since the index data in this case is two digits, the process proceeds from step _S4 to step _S6 , and the final result data of "4.722975 51" is displayed on the display section 1.
Displayed as 0.

In the above embodiment, the exponent digits are "2" and "3" digits, but they may be "4" and "5" digits.

As described above, according to the present invention, the exponent part and the mantissa part are configured fluidly, and the number of displayed digits of the mantissa part is changed according to the number of digits of the exponent data, so that the numerical range that can be displayed is It can be expanded, and calculations that could not be performed using conventional calculation methods can be performed, and can be extremely effective in practice.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a block diagram showing the circuit configuration, FIG. 2 is a diagram showing the detailed configuration of the register in FIG. 1, and FIG. 3 is a flowchart showing the operation contents. Chart 4, FIGS. 1 to 6 are diagrams showing changes in register contents and changes in display contents accompanying key operations. 1...Key input unit, 2...Control unit, 4...Memory for calculation, 7...Exponent digit detection unit, 8...Exponent digit number determination unit.

Claims (1)

[Claims] 1. In a small electronic calculator equipped with an exponent calculation function, there is a means for detecting the number of digits of the exponent in the calculation data, and a display unit that changes the number of digits of the mantissa data according to the number of digits of the exponent detected by this means. An index data display method characterized by comprising: display means.