JPS6329236B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a calendar information calculation method that calculates the number of days from a predetermined reference date based on given year, month, and day data, and also calculates date data for the month.

In recent years, electronic devices such as electronic watches and small electronic calculators that display calendars in various forms have been put into practical use. In order to display a calendar in this type of electronic equipment, the internal arithmetic processing circuit divides the number of days data obtained from a predetermined reference date by the numerical value "7" and also makes a predetermined correction. After obtaining day-of-the-week data for that day, it is common to perform a predetermined conversion process and display the data.

However, in the calculation process of the day of the week data,
In particular, the process of converting monthly data to number of days data is
For example, determine whether the month data is greater than "3", convert the given month data to month data for calculation based on the result, and add the month data to the month data for calculation. , multiplication by the numerical value "30.6", which takes into account the decimal point, and rounding off the result to the nearest whole number, requires a lot of calculation time in the above calculation processing circuit, and the calculation processing described above requires a lot of time. Circuit control also had to become more complex.

On the other hand, while various electronic calendar displays are being considered, there are many cases where it is necessary to calculate the non-day data of the month and perform month control based on the non-day data. The disadvantage was that it was necessary to determine whether the month was large or small, or whether it was a normal year or a leap year in the case of February, based on the given year and month data separately from the calculation process.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a calendar information calculation method that can easily perform conversion processing from month data to number of days data, and can simultaneously calculate unday data of the month. With the goal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, in which the present invention is applied to a case where a calendar for each week is displayed by operating a predetermined key in a small electronic calculator. FIG. 1 is an external perspective view of a small electronic calculator according to the present invention, and 1 is a key input section with a plurality of numeric keys and a function key 11.
It consists of a DATE key 12, a decimal point key 13, etc.
Note that this decimal point key 13 is also used as a calendar key, which will be described later, and the letters CAL indicating this are printed on the case of the computer. Reference numeral 2 denotes a display section for displaying input data, calculation results, etc., and is composed of a fluorescent display tube, a light emitting diode, a liquid crystal, or the like.

FIG. 2 is a circuit block diagram of this embodiment. 1 in the figure is the above key input section, and this key input section 1
The operation signal is input to the ROM address section 16, and by sequentially scanning a predetermined address line, a control signal for performing arithmetic processing corresponding to the key operation is sent from the ROM 17 to a predetermined circuit, that is, the X register 18, Y register 18, register 19, Z register 20,
A register selection signal R for selecting and specifying the A register 21 and the B register 22 is sent to the register specifying section 23.
Then, the timing selection signal TE for selecting and specifying the timing signal generated by the timing signal generating section 24 is sent to the timing specifying section 25, and the bit signal b ₁ is sent to the timing specifying section 25.
~b A code selection signal CODE for selecting a predetermined code signal from ₄ , and an instruction signal for causing the code signal generation section 26 to generate various control signals.
INS to the instruction decoder 27 and the next address signal NA for specifying its own next address.
are supplied to the ROM address section 16, respectively.

As shown in FIG. 3, the shift registers 18 to 21 have a total of 11 digits, including a flag digit F, a decimal point designation digit P, the first to eighth digits for data storage, and the most significant digit MSD, and receive timing signals _D1 to _D11. Each digit is specified by Note that the X register 18 also serves as a display register and is displayed on the display section 2. For convenience of explanation, the first to eighth digits of the X register 18 are
X _T , the first and second digits of the Y register 19 and Z register 20 are respectively Y _D , Z _D , the flag digit F of the B register 22, the decimal point designation digit P and the first to sixth digits
Let's call the digit B _T.

The outputs of the registers 18 to 21 are then given to the selector 28 together with the code signals, which include the first register designation signal F from the register designation section 23, the second register designation signal S, the timing signal T from the timing designation section 25, and the instrument Data to be input to the A and B input terminals of the adder circuit 29 is designated by the output gate control signal, code gate control signal, transfer signal, etc. from the traction decoder 27.

The adder circuit 29 executes a predetermined operation on the input from the selector 28 according to the binary coded decimal operation instruction BCD, subtraction instruction SUB, etc. from the instruction decoder 27, and outputs the data to the selector 3.
It is supplied to a 0 and 1 digit delay flip-flop circuit 31 and an AND circuit 32, and a carry (borrow) output is supplied to an AND circuit 33.

In addition to the data output of the adder circuit 29 and the output of the flip-flop circuit 31, the selector 30 is directly given an output from the selector 28 that should be input to the A input terminal of the adder circuit 29 without going through the adder circuit 29, and the instruction It is selected according to the carry signal LS and the carry down signal RS from the decoder 27 and is supplied to the gate circuits 34 to 38. The gate circuits 34 to 38 are supplied with the output of the selector 30 and each of the registers 18 to 2 that are circulated.
In addition to the output of 2, the first register designation signal F (F _X , F _Y , F _Z ,
F _A , F _B ), a gate control signal applied via an AND circuit 39 is supplied to control opening and closing, and cause each register 18 to 22 to store predetermined data. Note that a timing signal _TX from a timing specifying section 25 is applied to one input terminal of the AND circuit 39 to specify the timing for controlling the opening and closing of each of the gate circuits 34 to 38.

In addition, in FIG. 2, when performing various kinds of jump processing, the timing specifying section 25 supplies the timing signals Td and Tc to the AND circuits 32 and 33, and the instruction decoder 27 outputs the jump command Ju. The outputs of the AND circuits 32 and 33 are applied to the set-side input terminals S of the R-S flip-flop circuits 40 and 41, respectively, and the logical values of the set-side outputs J _L and J _H are changed. conduct. Note that the flip-flop circuit 40,
A timing signal is input to the reset side input terminal R of 41.
D ₁ , d ₁ , and φ ₂ are supplied, and the state is reset at each word time. The set side outputs J _L and J _H of the flip-flop circuits 40 and 41 are
It is supplied to the ROM address section 16 and reads the next address.
It is specified together with the next address signal NA of ROM17.

As described above, the ROM 17 outputs a predetermined control signal, which is applied to the register specifying section 28, timing specifying section 25, code signal generating section 26, instruction decoder 27, and the like. Incidentally, as shown in FIG. 2, the timing specifying section 25 includes
Timing selection signal given by ROM17
In addition to TE, a carry signal LS and a carry down signal RS are supplied to specify the timing of a timing signal T _x and the like for controlling the opening of the gate circuits 34 to 38. In addition to the code selection signal CODE, the code signal generating section 26 is also supplied with a timing signal T from the timing specifying section 25 to specify the timing at which the code signal is output. Furthermore, the instruction signal INS supplied to the instruction decoder 27 has a 4-bit configuration, for example, as shown in FIG.
In accordance with this instruction signal INS, the instruction decoder 27 outputs the gate control signal, code gate control signal, transfer signal, jump instruction JU, carry instruction LS, carry down instruction RS, subtraction instruction SUB, binary coded decimal modulo subtraction instruction
Outputs various control signals such as BCD.

Next, the operation of this embodiment will be explained. 5 and 6 are flowcharts for executing the calendar processing of the present invention, FIGS. 7 and 8 are diagrams showing register states and display states that change according to this flowchart, and FIG. A and B are diagrams for explaining the operation.

When the year, month, and day data to be displayed are entered through the key input unit 1, first, in step _S1 , the operated key is determined and the numeric value is entered. When the above-mentioned number processing is completed, the process proceeds to step _S2 , where the display register, that is, the X register 1
8 is sent to the display unit 2 and displayed.

Furthermore, "May 1978 AD" is currently in the X register 1.
The contents of the X register 18 are also transferred to the A register 21 (see FIG. 7 1), and the flag digit F contains DATE. Assume that "1" is stored by operating the key 12.

In this year, when the decimal point key (calendar key) 13 is operated following the key input of the month data, the process advances to step _S3 . In this step _S3 , "1" is stored in the flag digit F of the A register 21 to indicate whether the decimal point key (calendar key) 13 is used for numeric processing or for displaying a calendar. Detect whether or not it has been performed. In this case, since "1" is stored in the flag digit F of the A register 21 due to the operation of the DATE key 12, a YES determination is made and the process proceeds to step _S4 .
Step _S4 is a step in which it is determined whether "1" is stored in the flag digit F of the Z register 20, and it is determined whether the decimal point key (calendar key) 13 has already been operated. Since the decimal point key (calendar key) 13 has not been operated before then, the result is NO and the process proceeds to step _S5 . In step _S5 , as the decimal point key (calendar key) 13 is operated this time, a code signal "1" is stored in the flag digit F of the Z register 20 as shown in FIG. 7, and the process then proceeds to step _S6 . . In process _S6 , for the subsequent processing, the contents of the A register 21 are carried forward, the input year and month are followed by the day data "1", and the result is transferred to the X register 18. Transfer to X _T. As a result, the states of the A register 21 and the X register 18 are 7th.
It will look like Figure 4. Next, in step _S7 , the number of days and the month are calculated based on the year, month, and day data stored in the A register 21. FIG. 6 is a flowchart showing details of the above process _S7 ,
When the above process _S6 is completed, the process proceeds to step _S7-1 . That is, in step _S7-1 , it is checked whether the fourth digit of the X register 18 is `` ₁ '' or not. The adder circuit 29 subtracts the numerical value "3" from the 3rd and 4th digits, and the resulting output is input to the 3rd and 4th digits of the X register 18 via the selector 30 and gate circuit 34. In this case, the fourth digit _{of the}
It is determined whether the third digit of the register 18 is "3" or more. If it is determined in step _S7-3 that the third digit of the X register 18 is less than "3", the process advances to step _S7-4 and the X register 21
After adding the number "9" to the third and fourth digits,
The process proceeds to step _S7-5 , where a "-1" operation is performed on the contents of the fifth to eighth digits of the X register 18, and the process proceeds to step _S7-6 . In this case, X register 18
Since "5" is stored in the third digit, the process proceeds to step _S7-2 after completing step _S7-3 . As a result, the third and fourth digits of the X register 18 are "02"
(See Figure 7, 5). Above steps S _7-1
The year data and month data input into the X register 18 by _S7-5 are converted as shown in FIGS. 9A and 9B. In other words, if the year data at the time of input is a, the month data b, and the day data is c (=1), when b≧3, a′=a (no change) b′=b−3, when b<3, a′ =a-1 b'=b+9 will be transformed, so in this case X
The year data stored in the register 18 is "1978" (no change), and the month data is "02".

Next, after the above step _S7-2 is completed, processing for converting year data a and day data c into number of days data is carried out _S7-6
is executed. That is, in process S ₇ -6,
The converted year data a′ is multiplied by “36525”, and the day data c (=
1) and the result is added to B _T of B register 22.
(See FIG. 7, 6). In addition, in that case,
Data below the decimal point is input into the decimal point designation digit P and flag digit F, and integer data is input into the first to sixth digits.

When this process _S7-6 is completed, a flow for converting month data into number of days data is executed next. First, in step _S7-7 , the code signal "5" is sent to the selector 28 from the code signal generator 26.
The signal is supplied to the flag digit F of the X register 18 via the adder circuit 29, selector 30, and gate circuit 34, and is stored therein (see FIG. 7). next,
Step _S7-8 is executed to input the code signal "6" into the flag digit F of the Y register 19 in the same manner as in step _S7-7 (see FIG. 7). Then, in step _S7-9 , the first
Clear the digits to the 6th digit (see FIG. 7, 9). Next, the process proceeds to step _S7-10 , where "3" is input and stored in the tens digit of the non-date data, that is, the second digit of the Z register 20 (see FIG. 7, 10). After the steps _S7-10 are completed, determination of whether the month is large or small and processing of converting the day data b' into number of days data is performed. That is, as shown in FIG. 9A, when the content of the flag digit F of the Y register 19, that is, "6" is added to the flag digit F of the X register 18, and the carry output from the adder circuit 29 becomes "1" (the In Figure 9A, if the carry output is "1", it indicates O, and if it is "0", it indicates X.) If the carry output is "1", it indicates O, and if it is "0", it indicates '', processing for March, April...January is performed. First, in step _S7-11 , the flag digit F of the X register 18 and the flag digit F of the Y register 19 are added to determine the presence or absence of a carry output. Therefore, in this case, the addition result is ``11'', and the first value, ie, ``1'', is input again to the flag digit F of the X register 18 via the selector 30 and gate circuit 34 (see FIG. 7, 11). At the same time, the flip-flop circuit 41 is set to the set state by the carry output, the output _JH is supplied to the ROM address section 16, the next step _S7-12 is selected, and "1" is set in the first digit of the Z register 20. and set the month-end data (Z _D ) to "31" (see Figure 7, 12). In addition, step
If the carry output is determined to be "0" in _S7-11 , the process advances to step _S7-13 and the month data (Z _D ) is set to "30". Then, the process proceeds to step _S7-14 , where "1" is subtracted from the contents of the third and fourth digits of the X register 18 (i.e., the monthly data b' after conversion), and the resulting data is stored in the X register again. 18, enter the 3rd and 4th digits and follow the steps above.
Carry output is adjusted in the same way as S _7-11 .
In this case, the output is "01" as shown in Fig. 7, 13, so the carry (borrow) output is "0" and the next step is step _S7.
-15, and the number of days stored in the first to sixth digits of the B register 22 is entered in the Z register 20.
The data stored in the first to sixth digits, ie, "31" is added (see FIG. 7, 14), and the process returns to step _S7-11 , whereupon the same processing is performed. That is, this time, in step _S7-11 , the carry output is determined to be "0" as shown in FIG.
Proceeding to step _S7-13 , "30" is stored in _ZD as undateable data as shown in FIG. 716. Then, following this step _S7-13 , the same adjustment as described above is performed in step _S7-14 , but this time the carry output is determined to be "0" (see Fig. 7, 17), so the step S7-14 is performed. At _S7-15 , undateable data ( _ZD ) "30" is added to the first to sixth digits of the B register 22 (see FIG. 7). Thereafter, the same process is repeated, and as shown in Figure 9A, the number of days data "31" and "30" are selected and added as appropriate to calculate the number of days until the relevant month.In this case, the next processing flow At this point, the calculation jump processing is performed as shown in FIGS. 19-21, and the carry output becomes "1" at step _S7-14 , and the process advances to step _S7-16 . This step S ₇ −
16 and the next step _S7-17 are steps for determining whether or not the month data b stored in the A register 22 is "02". If the month data b is determined to be "02", Proceeding to step _S7-18 , "2" is input into the second digit of the Z register 20. Following this step _S7-18 , step _S7-19 is executed to check whether "7" is stored in the decimal point P of the B register 22. That is, as shown in FIG. 9B, as a result of calculating the number of days in step _S7-6 , the flag digit F and decimal point digit P of the B register 22 contain "75" if it is a leap year, "00" if it is a normal year, Since data of either "25" or "50" is stored, if "7" is determined in step _S7-19 , the process advances to step _S7-20 and the Z register 20 is stored.
Store "9" in the first digit of the date data (Z _D )
is set to ``29'', and if it is determined at step <sub>S7-19</sub> that it is other than ``7'', the process advances to step _S7-21 , and Z
"8" is stored in the first digit of the register 20, and the undateable data (Z _D ) is set to "28". And this step
_S7-20 , _S7-21 Proceed to end processing _S3 (see Figure 5).

However, in this case, NO at step S _7-17 .
A decision is made and steps S ₇ -18 to S ₇
Proceed directly to processing _S3 without going through the processing of −21. and,
In this process _S3 , the number of days data obtained in the above process _S7 (i.e., this number of days data is obtained based on the hypothetical reference date of March 1, 2007), starting from this reference date. (This is the number of days data.)
is divided by "7", the remainder is determined, and a predetermined correction is applied to determine the day of the week data for the first day of the month. For example, "0" is Sunday and "1" is the day of the week data.
corresponds to Monday, and "6" corresponds to Saturday.
Therefore, in this case, as shown in Figure 7 22, this day of the week data is "1", which means "May 1, 1978 A.D."
is determined to be Monday. Then, the process proceeds to step _S9 , where it is checked whether the flag digit F of the Z register 20 is "1" or not. In other words, this step
_S9 determines whether to proceed to step _S11 to determine the day of the week, which will be described later in the past, or to proceed to step _S10 to display a weekly calendar. As mentioned above, Z register 20
Since "1" is stored in the flag digit F,
Proceeding to step _S10 , the blanking code BL is input into X _T of the X register 18. Subsequently to this step _S10 , steps _S12 and _S13 are executed to input "7" into the decimal point designation digit P of the X register 18, and clear _YD of the Y register 19. The register states of the X register 18, Y register 19, and Z register 20 at the end of step _S13 are shown in FIG. 723.

Following the preprocessing up to step _S13 , data for displaying the calendar for the first week of the month is created. First, in step _S14 , it is determined whether the date data (Y _D ) and the non-date data (Z _D ) match. In other words, Y register 1 is used as the first register.
9. Designate the Z register 20 as the second register and input the first and second digits of each register 19 and 20 from the A and B input terminals of the adder circuit 29 to perform subtraction. In this case, since Y _D is "0", the data output and carry output from the adder circuit 29 cause the flip-flop circuit 4 to
1 and 42 are both set, and the outputs J _L and J _H are set to “1”.
shall be. However, as the next step,
_S15 is selected. In step _S15 , the date data (Y _D ) is subjected to a "+1" operation, which in this case becomes "1". Then proceed to step _S16 ,
In the same manner as described above, it is checked whether the flag digit F of the Y register 19 is "0" or not. In this case,
Since "1" is stored in the flag digit F of the Y register 19, the judgment result is NO and the process proceeds to step _S20 . Step _S20 is a step for transferring the first digit of the date data (Y _D ) to the first digit of the X register 18, where "1" is stored in this case. Then, the process advances to the next step _S21 , and a "+1" operation is performed on the day of the week data (stored in the flag digit F of the Y register 19). As a result, the day of the week data becomes "2", so a negative determination is made in the next step _S22 , and the process proceeds to step _S23 . In step _S23 , X _T in the X register 18 is carried up as described above in preparation for the next data input. Therefore, the register state at the end of step _S23 is as shown in FIG. 81.

Similarly, step S ₁₄ →S ₁₅ →S ₁₆ →S ₂₀ →S ₂₁ →
Repeat S ₂₂ → S ₂₃ to process the processing from the second day of the first week (in the current case, "Tuesday, the 2nd") to the fifth day (in the current case, "Friday, the 5th"). ~ Proceed as in 3. And on the 6th day (in this case “6th day”)
"Saturday") is processed in the same way (Figure 8, 4).
However, this time, in step _S23 , the content of flag digit F of Y register 19 is determined to be "7", so proceed to step _S24 and clear the content of flag digit F of Y register 19. After that, step S ₂
The display proceeds to step 8 and is displayed as shown in FIG. 5.

By continuing to operate the decimal point key (calendar key) 13, processing for displaying the calendar for the second week is executed. That is, steps _S3 and _S4 are executed first as described above, but since "1" is stored in the flag digit F of the Z register 20 this time, after step _S4 is completed, the process proceeds to step _S25 .
In step _S25 , the date data (Y _D ) and non-date data (Z _D ) are compared in the same manner as in step _S14 . Currently, Y _D is "06", so
Proceeding to step _S15 , "+1" operation is performed on the date data (Y _D ) in the same manner as above. This step
After completing _S15 , the process proceeds to step _S16 , and it is checked whether the flag digit F of the Y register 19 is "0" or not.
Since the content is currently ``0'', a YES judgment is made, and this time, proceed to step _S17 . In step _S17 , it is determined whether the second digit of the Y register 19, that is, the value of the tenth digit of the date data, is "0". As a result, if the data is not "0", a NO judgment is made,
Proceeding to _{step S13} , the data in the second digit of the Y register 19 is transferred to _the second digit of the After the determination is made, step _S19 is selected as the next step, the blanking code BL is stored in the second digit of the X register 18, and the process proceeds to step _S20 . Similarly, steps S ₂₀ to _{S 23}
and inputs Sunday date data (“7” in this case) into the X register 18. Figure 8 6
Step S ₂₂ after entering data for Sunday
This is the state at the end. As described above, steps S ₁₄ →S ₁₅ →S ₁₆ →S ₂₀ →S ₂₁ →S ₂₂ →S ₂₃ (or S ₂₄ in the case of Saturday) are executed to process the data for the second week as shown in FIG. 7 to 8, and the display is as shown in FIG. 9.

Below, decimal point key (calendar key) 13
In response to the operation, the third and fourth weeks are processed and displayed as shown in FIG. 8. In addition, Fig. 8 10, 1
2 shows the register states at the end of the processing in the third and fourth weeks, respectively, and FIGS. 11 and 13 show the display states in the third and fourth weeks.

Continuing to operate the decimal point key (calendar key) 13, the processing for the 5th week is performed as shown in Figure 8, 14, 15..., but "1" (meaning "31") is stored in the X register as unday data. After inputting the blanking code BL to the first digit of the X register 18, the blanking code BL is inputted to the first digit of the X register 18 in step _S26 in order to make all the digits below it blank. And this step S ₂₆
After completion of step _S21 , the blanking code BL is input up to the first digit by repeating steps _S21 → _S22 → _S23 → _S14 → _S26 . 15 shows the status of the registers 18 and 19 at the end of processing on Wednesday, FIG. 16 shows the status of the registers 18 and 19 at the end of processing on Thursday, FIG. are shown respectively.

And furthermore, decimal point key (calendar key) 1
When 3 is operated, the year and month data for the next month are obtained and displayed. That is, first, when the decimal point key (calendar key) 13 is operated after displaying up to the fifth week, steps _S3 and _S4 are executed, and the process proceeds to step _S25 . Since the date data (Y _D ) is currently "31", the result of the jump in step S ₂₅ matches the month data (Z _D ),
The result is YES, and the process proceeds to step _S27 . In process _S27 , year and month data for the next month are created based on the year and month data stored in the A register 21. Next, proceed to step _S23 , and set the flag digit F of the Z register 20.
is cleared and set to "0". This means that if the decimal point key (calendar key) 13 is continued to be operated,
Step S After performing preprocessing such as calculating the day of the week data and non-day data for the first day of the month from ₆ onwards, the first
This is to create a weekly calendar. The states of registers 18, 20, and 21 at the end of step _S23 are as shown in FIG. 8 and 19, and the contents of this X register 18 "1978.06" are displayed in the next step _S2 . The display state is shown in FIG.

Then continue with the decimal point key (calendar key)
13 is operated, as described above, after preprocessing, calendar processing for the first week of the month is performed, and the decimal point key (calendar key) is
It goes without saying that calendar processing is performed and displayed sequentially in response to the operations in step 13.

Note that it is also possible to display the day of the week data for that day by inputting year, month, and day data from the key input unit 1 as in the past, and this will be explained below with reference to the flowchart of FIG. 5. For example, how to input the calendar information is □1□9□7□8DATE□5DATE□1
Like DATE, numeric keypad 11, DATE key 1
This is done according to 2. This input is performed in the same way as in the key input method described above, by repeating processing _S1 and step _S2 , and carrying out processing such as carrying. And 3
When the second operation of the DATE key 12 is detected in process _S1 , the process jumps to process _S7 . This process s ₇
Then, the number of days is calculated based on the input year, month, and day data as described above, and after this calculation is completed, the process proceeds to step _S3 . In process _S8 , the day of the week data of the key-input day is calculated from the number of days data (X) obtained in process _S7 , as described above. As a result, Y
Flag digit F of register 19 is "1" in this case.
becomes. Next, proceed to step _S9 and register Z register 20.
It is checked whether the flag digit F is "1" or not, but in this case, the result of the check is NO, and the process advances to step _S11 . In this process _S11 , the day of the week data obtained in process _S8 is converted into data suitable for the display format. Specifically, if you want to indicate the day of the week numerically,
By inputting the day of the week data after carrying out a carry process etc. to a predetermined digit of the This is done by inputting this into the decimal point designation digit P of the X register 18.

In the above embodiment, as shown in FIG. 9A,
We added "6" sequentially to the initial value "5" and judged whether the month was large or small depending on the presence or absence of carry output at that time. For example, as shown in Figure 10, "6" was added sequentially to the initial value "4". It is also possible to determine whether the month is large or small by adding .

In addition, it is also possible to sequentially subtract "6" from the initial value "5" and use the borrow output at that time to determine whether the month is large or small in the same way as above. The method is not limited to the above examples.

Furthermore, in the above embodiment, the calendar information calculation method of the present invention is applied to displaying a weekly calendar or displaying the day of the week of the day of key input, but it is also possible to display one month's calendar in a row. It goes without saying that the present invention can also be applied to cases where a regular seven-day table is displayed electronically.

In addition, in the above embodiment, the case where the calendar is displayed in a small electronic calculator has been described, but the calendar information calculation method of the present invention can also be used to calculate calendar information in electronic equipment such as an electronic clock. However, it is also possible to display a predetermined calendar.

It goes without saying that various other modifications and applications can be made without departing from the gist of the present invention.

The "input means" of the present invention is the key input unit 1, the "conversion means" is the X register 18, the adder circuit 29, the "calculation means" is the X register 18, the Y register 19, the adder circuit 29, and the "days data calculation means" is These correspond to the Z register 20, B register 22, and adder circuit 29, respectively.

As described in detail above, the present invention simplifies the arithmetic processing of converting input month data into day data, and at the same time makes it possible to determine whether the month is large or small. It is possible to simplify the control, thereby shortening the calculation processing time, and by reducing the number of steps that need to be microprogrammed in the ROM, the increase in the number of steps required for other calculation processing can be avoided. This is very effective in designing possible arithmetic processing circuits.

[Brief explanation of the drawing]

1 to 9 show an embodiment of the present invention,
Fig. 1 is an external perspective view of the small electronic calculator according to this embodiment, Fig. 2 is its circuit block diagram, Fig. 3 is a diagram showing instruction signals for generating various control signals, and Fig. 4. is a register configuration diagram in FIG. 2, FIG. 5 is a flowchart for explaining the operation of this embodiment, FIG. 6 is a detailed view of the main part of the flowchart in FIG. 5, and FIGS. The figure shows the registers and display states that change sequentially according to the flowcharts in Figures 5 and 6. Figure 9 is a diagram conceptually showing the method of calculating the number of days data and undateable data in this embodiment. 10 is a diagram showing a modification of the main part of FIG. 9. 1...Key input section, 2...Display section, 12...
DATE key, 13... Decimal point key, 16...
ROM address section, 17...ROM, 18...X
Register, 19...Y register, 20...Z register, 21...A register, 22...B register, 26...code signal generator, 27...instruction decoder, 28...selector, 29
...Adder circuit, 30...Selector.

Claims (1)

[Claims] 1. An input means for inputting at least year and month data, and a conversion means for converting the input month data into calculation month data counted from the base month of the year;
A calculation means for repeatedly adding or subtracting a predetermined value from a predetermined reference value as many times as the calculation month data obtained by the conversion means, and determining the end of the month of a large month or a month of a small month based on the carry or borrow output of the calculation means. A calendar calculation device comprising a number of days data calculation means for calculating number of days data from the calculation month data by selecting and sequentially adding days "30" and "31".