JPS63251825A - Control system for real time timer - Google Patents

Abstract

PURPOSE:To improve the resolution with the minimum hardware quantity by adding the contents of a counter to the contents stored in a real time timer area via an arithmetic means in response to an interruption request and replacing said timer area according to the result of said addition. CONSTITUTION:For instance, the time pulses of one millisecond are counted by a 10-bit binary counter 23 and at the same time a microprogram produces an interruption request by the overflows occurring every 2<10>=1,024 milliseconds, i.e., a single cycle of the counter 23. In response to this interruption request, the contents of a real time timer area of a memory unit 3 are added to the contents of the counter 23. Then the contents of said timer area are replaced based on the result of said addition. Thus a real time timer is obtained. When the real time timer is read out, the contents of the timer area are added to the present contents of the counter 23. Then the value of this addition is defined as the read value of the real time timer. Thus it is possible to obtain a real time timer having high resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of the Invention The present invention relates to a real-time timer control system, and particularly to a control system for a real-time timer device that is a crystal clock mechanism in an information processing device.

Sarame and I Many information processing devices have various timers that can be used in software, a typical one of which is a real-time timer. A real-time timer is a means for a program to know the time by reading its value, and is often expressed in hexadecimal. In an information processing device using microprogram control, if the resolution of the timer is relatively coarse, a real-time timer can be realized using hardware with low R.

In other words, the microphone [I
In addition to providing a means for requesting an interrupt in the program, a real-time timer area is prepared in advance in the storage means that can be referenced by the microprogram, and this is controlled with the general arithmetic circuit every time an interrupt request is generated. The real-time timer area can be updated using a microprogram that corresponds to the device specifications.

However, if high resolution is required for the timer, this method will cause frequent interrupts to update the timer, degrading system performance. The disadvantage is that dedicated hardware is required.

Therefore, the present invention was made to eliminate such drawbacks of the conventional ones, and its purpose is to realize a high-resolution real-time timer with the minimum amount of hardware. An object of the present invention is to provide a real-time timer control method in an information processing device.

According to the present invention, there is provided a real-time timer control method in a microprogram-controlled information processing device, which includes a counter that is clocked by a clock pulse, and an interrupt request to the microprogram caused by an overflow of the counter. a storage means having an area for a real-time timer, and in response to the interrupt request, the content of the counter is adding the contents stored in the area by the calculation means, updating the real-time timer area with the result of the addition, and responding to a real-time timer read instruction from the microprogram;
A real-time timer control system is obtained, characterized in that the contents of the counter and the contents stored in the real-time timer area are added and the addition result is used as a read value of the real-time timer.

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

FIG. 1 is a block diagram of a real-time timer device according to an embodiment of the present invention, in which a timer unit 822, working storage unit I, and 3° arithmetic unit 4 are interconnected by a 32-bit wide bus 1.

The timer unit 2 includes a generator 21 that generates a clock pulse 22 every millisecond and a clock 10 that is incremented by the clock pulse.
It includes a bit binary counter 23.

The binary counter has an overflow bit that sets a carry from the most significant bit, and outputs a microprogram interrupt request signal 24 when this bit is set. The contents of the binary counter and the overflow bit can each be reset by instructions from the microprogram and can be output to the bus.

The working memory unit 3 includes a working memory that can be addressed by a microprogram to write 4 bytes of data on the bus, and read its contents onto the bus.

The arithmetic unit 4 has arithmetic unit 41.3 registers 42.4
3.44 and a constant generation circuit 45, and is controlled by a microprogram. Arithmetic unit 41 is A register 42
Alternatively, the Q register 43 is used as the left input, and the B register 4
4 or the output of the constant generation circuit 45 as the right input,
Logical operations on 32-bit wide data, binary addition/subtraction and 1
Performs 0-base addition and subtraction and stores the output in the A register or Q register. The constant generation circuit 45 has a function of expanding the 8-bit constant field in the microinstruction word to 32 bits and outputting it.

A carry in an addition/subtraction is stored in a carry flip-flop 46, and this state can be determined by a microprogram and can be used as a carry input for subsequent addition/subtraction. All three registers 42-44 are on bus 1
It is connected to the bus, and can capture and store data on this bus, and output its contents to the bus. Also, A
The contents of the register 42 and the Q register 43 can be shifted sequentially or concatenated.

FIG. 2 illustrates the data format of the real-time timer of this information processing apparatus, and is expressed in 8-byte hexadecimal with a 24-hour period. Figure 3 shows the data format on the bus when the binary counter for the timer is output to the bus.The overflow bit status and the 10-bit binary counter value are output to the bus in a left-justified manner. .

The initial value of the real-time timer of this information processing device is set by a software instruction. At this time, the microprogram resets the binary counter 23 including the overflow bit, reads the real-time timer setting value in the format shown in FIG. They are stored in the real-time timer area of 2 words in 3 (hereinafter referred to as TIMH and TIML). Thereafter, the binary counter increments every millisecond, and when a digit error occurs, it outputs an interrupt request signal 24 to the microb 0gram.

FIG. 4 is a flowchart of a microprogram activated by an interrupt from the binary counter 23. When the microprogram receives an interrupt from the binary counter 23, it first resets the overflow bit of the binary counter in step (a), and then resets the working memory unit in steps (b) to (d).・Set the real time timer value in the A and Q registers and shift it to the right by 8 bits. Next, in steps (e) to (0), the second and millisecond display digits in the Q register are set to 2.
A constant corresponding to one cycle of the decimal counter (2" = 1024 milliseconds) is added in decimal. - Furthermore, this value is subjected to sexagesimal correction using the V blue routine, and steps (h) and (i
) to access the real-time timer area in the working memory unit.

FIG. 5 shows the 70-digit subroutine for sexagesimal correction. First, in step (a), ° "60" is subtracted in decimal form from the second display digit in the Q register, and in step (b), the presence or absence of a carry (indicated as C in the flowchart) is determined to display the second. Check whether the digit is "60" or more. If it is less than "60", in step (C) add '60' to the seconds display digit (in other words, return the seconds display digit to its original value), and in step l) return the display digit position to its original form. If the second display digit is "60" or more, the minute display digit is set to "59" in steps (d) to (f).
Check whether it is greater than or equal to ``5'9'': If it is less than ``5'9'', add 60'' in decimal to the minute display digit in step (0), that is, add ``1'' to any minute display value. ), the display digit position is returned to the original position in steps (k) and (ρ), and the process ends.

If the minute display digit is “59” or more, step (h), (
i) Check whether the hour display digit is ``23'' and ``23''.
If it is less than “23”, step (j) sets “24” to the hour display digit.
'' is added as a decimal, i.e., add 1pa to the hourly displayed value), and if it is ``23'' or more, leave it as is (that is, the hourly displayed value remains 00''), step (k), (ρ)
Return the displayed digit position to the original position and exit.

FIG. 6 is a flowchart showing the processing when reading out the real-time timer value is instructed by a software instruction. First, in steps (a) and (b), the A register is cleared and the value of the binary counter, including the overflow bit, is loaded into the Q register and the B register. Step (C)
Now, by adding 8 registers to the Q register in binary, the binary number in the Q register is doubled, and the leftmost bit is set in the carry flip-flop. In step (d), the value of the carry flip-flop is set to 8 as the carry input.
By adding the decimal register to the A register,
The decimal number in the A register is doubled and the carry in step (C) is added. Steps (C) and (d) 11
By repeating this several times, the 11-bit binary number stored left-justified in the Q register becomes io'i! It is converted into a number and stored in the A register right-justified. Then step (
In e) to (h), the value in the A register is shifted to the left by 12 bits, then transferred to the 8th register, the real-time timer value in the working memory unit is loaded into the A and Q registers, and the value is shifted to the right by 8 bits.
Bitsif! ·do. That is, the value of the binary counter is stored in the B register, and the lower digits of the real-time timer value are stored in the Q register as 5-digit decimal numbers, left-justified. Furthermore, after decimal addition of these values in step (i), sexagesimal correction is performed in the 1-knob routine, and step (i) is performed.
In steps j) and (k), this is stored in the main memory address specified by the software instruction, and the process ends.

In this way, for example, a 1 millisecond clock pulse is counted by the 10-bit binary counter 23, and an interrupt request is generated to the microprogram due to overflow every 210 = 1024 milliseconds, which is one period of this counter. let me,
In response to this interrupt request, the content of the real-time timer area on the storage unit 3 is added to the content of the counter 23, and the content of the real-time timer area is updated based on the addition result. Configuring a time timer. When reading this real-time timer, add the contents of the real-time timer area and the current contents of the binary counter,
This added value is used as the real-time timer read value.

By doing so, it is possible to have a configuration in which nine hardware circuits including a counter, a storage means, and a performance means are controlled by a microprogram, and a real-time timer with high resolution can be realized. Furthermore, if a subroutine for sexagesimal correction is set, it becomes a real-time timer with sexagesimal display.

Effects of the Invention As described above, according to the present invention, a real-time timer with high resolution can be constructed by using hardware and microprogram control.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a real-time timer according to an embodiment of the present invention, Fig. 2 is a diagram showing the data format of the real-time timer in this embodiment, and Fig. 3 is a binary representation for the real-time timer. Figure 4 shows the data format when the contents of the counter are output to the bus. Figure 4 is a flowchart of the microprogram activated by an interrupt request from the binary counter. Figure 5
This figure is a flowchart of a microprogram subroutine for performing sexagesimal correction, and FIG. 6 is a flowchart of a microprogram for performing read processing of a real-time timer. Explanation of symbols of main parts 1... Bus 2... Timer unit 3... Working memory unit 4... Arithmetic unit 21... Pulse Generator 23...Counter 41...Arithmetic unit

Claims (1)

[Claims] A real-time timer control method in a microprogram-controlled information processing device, which includes a counter that increments based on a clock pulse, a means for generating an interrupt request to the microprogram when the counter overflows, and an arithmetic operation having an arithmetic function. and storage means having a real-time timer area, and in response to the interrupt request, the arithmetic means adds the contents of the counter and the contents stored in the real-time timer area. The real-time timer area is updated based on the addition result, and in response to a real-time timer read instruction from the microprogram, the contents of the counter and the contents stored in the real-time timer area are added. A real-time timer control method characterized in that the addition result is used as a read value of a real-time timer.